diff --git a/CLAUDE.md b/CLAUDE.md
index fea2c45..9a6309a 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -556,3 +556,64 @@ network) needs `host.docker.internal:PORT` in the Caddyfile, not
 so that hostname resolves; `configure_caddy_for_service`'s bare-port upstream
 case already does this for you — don't hand-roll `localhost:PORT` in a
 Caddy site block.
+
+## Shared coturn (TURN/STUN) relay
+
+Any service that needs a TURN server for WebRTC/SIP NAT traversal shares
+**one** coturn instance (`services/coturn.sh`) instead of running its own.
+This exists because it didn't always: `asterisk` and `mattermost` used to
+each embed a dedicated coturn container (`network_mode: host`, each with its
+own relay port range) — confirmed live, their default ranges overlapped by
+~100 UDP ports, so running both on one box meant a coin-flip over which
+service's active call lost its media relay. One shared instance with one
+port range removes the collision instead of just moving it around.
+
+**Use `ensure_coturn_user` (`lib/common.sh`), not your own coturn container:**
+
+```bash
+ensure_coturn_user "my-service"
+if [ -n "$COTURN_HOST" ]; then
+    # Out-params (not `local` — read them after the call returns, same
+    # convention as configure_caddy_for_service's CADDY_SERVICE_*):
+    #   COTURN_HOST COTURN_PORT COTURN_USERNAME COTURN_PASSWORD
+else
+    # coturn unavailable (not installed and services/coturn.sh isn't loaded
+    # to chain-install it — e.g. this file run fully standalone) — degrade
+    # gracefully. Don't block the rest of your install on this.
+fi
+```
+
+`ensure_coturn_user` chain-installs `services/coturn.sh` the first time
+*any* service needs one (guarded with `declare -F install_coturn`, same
+pattern as the asterisk → security-dashboard chaining below), then
+registers a dedicated long-term-credential username/password for your
+consumer name. The credential is cached in
+`~/docker/coturn/users/<consumer>.env`, so calling this again on a rerun
+reuses the same credential instead of minting a new one and silently
+orphaning whatever client already has the old one configured.
+
+**Why long-term credentials (`--lt-cred-mech`), not the REST-API/HMAC mode
+(`--use-auth-secret`) some WebRTC apps default to:** coturn does not support
+running both auth mechanisms on one instance at once — enabling
+`--use-auth-secret` silently overrides `--lt-cred-mech` server-wide, which
+would break every static-credential consumer. `--lt-cred-mech` supports any
+number of named users out of the box, which is the actual shape a
+shared-multi-consumer coturn needs. If the service you're adding only
+exposes an HMAC-secret TURN setting in its own UI (no plain
+username/password option), check its docs for an alternative field first —
+Mattermost's Calls plugin looked HMAC-only at a glance but also accepts a
+fixed username/credential pair via its "ICE Servers Configurations" JSON
+field (see `services/mattermost.sh` for the exact format). Don't fall back
+to a second coturn instance just because the first field you found expects
+a shared secret.
+
+**Migrating an existing service from its own embedded coturn:** don't do it
+silently. An `update` rerun must keep whatever coturn shape a service
+already has — detect the existing embedded container (e.g. `grep -q '^
+coturn:' docker-compose.yml` before regenerating it) and preserve it
+exactly, the same non-destructive rule as every other `update` path in this
+file. Only switch to the shared coturn on an explicit `fresh` reinstall, and
+warn before doing it — the TURN username/password changes, and any
+already-configured client (a SIP phone, a browser session) keeps the old
+credentials until it's reconfigured. See `services/asterisk.sh`'s
+`USE_EMBEDDED_COTURN` handling for the reference pattern.
diff --git a/README.md b/README.md
index 36ce734..9fbf20e 100644
--- a/README.md
+++ b/README.md
@@ -67,13 +67,13 @@ a ready-to-copy Caddy config snippet to `~/docker/caddy-snippets/`.
 | Group | Services |
 |-------|---------|
 | `base` | `net-tools`, `ncdu`, `git`, `curl`, `wget`, `htop`, `tree`, `zip`/`unzip`, `ca-certificates`, `gnupg`, `jq`, `rsync`; `glow` (terminal markdown reader, Charm apt repo); Docker CE + Compose plugin; `openssh-server` with GitHub/Launchpad SSH key import, optional password-auth lockdown, and SSH Host aliases; optional NetBird overlay network |
-| `homelab` | `caddy`, `crowdsec`, `authelia`, `homeassistant`, `asterisk`, `pstn-trunk`, `sms-inbound`, `security-dashboard`, `sunshine` |
+| `homelab` | `caddy`, `crowdsec`, `authelia`, `coturn` (shared TURN/STUN relay — Asterisk, Mattermost Calls, and future WebRTC-capable services all register a dedicated credential against one instance instead of each running its own), `homeassistant`, `asterisk`, `pstn-trunk`, `sms-inbound`, `security-dashboard`, `sunshine` |
 | `utilities` | `actualbudget`, `ai-gpu`, `ai-stack`, `archivebox`, `changedetection`, `ddclient`, `filebrowser`, `fmd`, `gatus`, `homebox`, `iopaint`, `joplin`, `koha`, `magicmirror`, `mail-archiver`, `mattermost`, `mealie`, `meshcentral`, `n8n`, `nextcloud`, `ntfy`, `onlyoffice`, `paintplus`, `portainer`, `rustdesk`, `stirling-pdf`, `syncthing`, `traccar`, `unifi`, `uptimekuma`, `vaultwarden`, `watchyourlan`, `watchtower`, `wg-easy` |
 | `media` | `arm`, `audiobookshelf`, `calibre-web`, `emby`, `immich`, `jellyfin`, `lyrion` |
 | `cameras` | `frigate`, `frigate-audio`, `frigate-notify`, `sky-cam` |
 | `gaming` | `drum-rhythm-game`, `js99er`, `kyber-launcher`, `kyber-server`, `minecraft`, `wolf`, `wolf-pair` |
 | `extras` | `kdeconnect`, `silent-send`, `ssh-config`, `sync-cc` |
-| `backup` | `backup` — complete recovery: entire `~/docker/<service>/` for every service via Kopia (Minecraft: flush+snap, no downtime; others: stop/snap/start for DB consistency); `borg-backup` — same coverage via Borg (chunk dedup, SSH remote repos, Borgmatic/Vorta compatible); `gaming-backup` — frequent game-save snapshots (Minecraft world data, emulator saves, Steam — no downtime, run hourly) |
+| `backup` | `backup` — complete recovery: entire `~/docker/<service>/` for every service via Kopia (Minecraft: flush+snap, no downtime; others: stop/snap/start for DB consistency), optional offsite mirror (`kopia repository sync-to`), plus `dr_bringup.sh` — unattended restore-everything-and-start for standing up a cold spare box; `borg-backup` — same coverage via Borg (chunk dedup, SSH remote repos, Borgmatic/Vorta compatible); `gaming-backup` — frequent game-save snapshots (Minecraft world data, emulator saves, Steam — no downtime, run hourly) |
 
 Run `./setup.sh --list` to see descriptions.
 
diff --git a/extras/backup_kopia.sh b/extras/backup_kopia.sh
index 5a9dac0..39fe9ea 100644
--- a/extras/backup_kopia.sh
+++ b/extras/backup_kopia.sh
@@ -170,6 +170,29 @@ if [ "${REMOTE_TYPE:-none}" != "none" ] && [ -n "${REMOTE_TYPE:-}" ]; then
     done
 fi
 
+# ── Keep a spare box's copy of backup.conf + README current ─────────────────
+# Runs after the data itself is backed up (and mirrored, if configured) so a
+# sync never ships config pointing at a repo state that isn't actually there
+# yet. dr_bringup.sh on the spare only needs these two small files — the
+# repo data itself already lives wherever REMOTE_TYPE mirrored it (or is
+# local, if the spare IS that target).
+if [ -n "${DR_SYNC_HOST:-}" ]; then
+    _dr_path="${DR_SYNC_PATH:-~/docker/backup}"
+    log "Syncing backup.conf + README to spare ($DR_SYNC_HOST:$_dr_path)..."
+    _dr_files=("$CONF")
+    [ -f "$HERE/README.md" ] && _dr_files+=("$HERE/README.md")
+    if ssh -o BatchMode=yes -o ConnectTimeout=10 "$DR_SYNC_HOST" "mkdir -p '$_dr_path'" 2>"$_ERR" \
+        && scp -o BatchMode=yes -o ConnectTimeout=10 "${_dr_files[@]}" "$DR_SYNC_HOST:$_dr_path/" 2>>"$_ERR" \
+        && ssh -o BatchMode=yes -o ConnectTimeout=10 "$DR_SYNC_HOST" "chmod 600 '$_dr_path/backup.conf'" 2>>"$_ERR"; then
+        log "OK spare sync ($DR_SYNC_HOST)"
+    else
+        _reason="$(categorize_error "$(cat "$_ERR")")"
+        log "WARNING: spare sync failed — $_reason"
+        FAILED_SVCS+=("spare-sync: $_reason")
+        rc=1
+    fi
+fi
+
 DURATION=$(( $(date +%s) - START_TS ))
 DURATION_STR="$((DURATION/60))m $((DURATION%60))s"
 
diff --git a/extras/dr_bringup_kopia.sh b/extras/dr_bringup_kopia.sh
new file mode 100644
index 0000000..48ca048
--- /dev/null
+++ b/extras/dr_bringup_kopia.sh
@@ -0,0 +1,242 @@
+#!/bin/bash
+# extras/dr_bringup_kopia.sh — non-interactive disaster-recovery bring-up.
+# Installed to ~/docker/backup/dr_bringup.sh by the backup service installer.
+#
+# Restores the LATEST snapshot of every backed-up service (or one chosen
+# service) straight into place and brings it up with `docker compose up -d`.
+# Meant to run unattended on a cold spare box during a real outage — unlike
+# restore_kopia.sh (one service at a time, interactive prompts per step),
+# this walks every discovered service with no prompts so it can complete a
+# full-stack recovery in one command.
+#
+#   sudo ./dr_bringup.sh                 restore + start every service
+#   sudo ./dr_bringup.sh --service NAME  restore + start one service
+#   sudo ./dr_bringup.sh --list          list restorable sources and exit
+#   sudo ./dr_bringup.sh --dry-run       show what would happen, touch nothing
+#   sudo ./dr_bringup.sh --no-start      restore only, skip docker compose up -d
+#
+# Reads backup.conf from the same directory. On the spare box this file
+# won't exist yet on its own — copy it over from the primary box first (it
+# holds the repository paths/passwords needed to connect):
+#   scp primary:~/docker/backup/backup.conf ~/docker/backup/backup.conf
+# If the destination repo is a local path shared with the primary (e.g. the
+# spare box IS the box the primary's REMOTE_TYPE=sftp mirror targets),
+# nothing else is needed — the repo data is already there.
+set -uo pipefail
+
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+CONF="${BACKUP_CONF:-$HERE/backup.conf}"
+
+RED='\033[0;31m'; GREEN='\033[0;32m'; YELLOW='\033[1;33m'; BLUE='\033[0;34m'; NC='\033[0m'
+info() { echo -e "${BLUE}[INFO]${NC}  $*"; }
+ok()   { echo -e "${GREEN}[OK]${NC}    $*"; }
+warn() { echo -e "${YELLOW}[WARN]${NC}  $*"; }
+err()  { echo -e "${RED}[ERROR]${NC} $*" >&2; }
+die()  { err "$*"; exit 1; }
+
+# ── Preflight ─────────────────────────────────────────────────────────────────
+[ "${EUID:-$(id -u)}" -eq 0 ] || die "Run as root: sudo $0"
+[ -f "$CONF" ]                 || die "backup.conf not found: $CONF — copy it from the primary box first."
+command -v jq >/dev/null 2>&1  || die "jq is required — install it: sudo apt install jq"
+
+# shellcheck source=/dev/null
+source "$CONF"
+
+# gaming-backup's single-dest conf format normalises the same way restore_kopia.sh does.
+if [ -z "${DEST_NAMES:-}" ]; then
+    DEST_NAMES="default"
+    DEST_default_CONFIG="${KOPIA_CONFIG:-}"
+    DEST_default_PASSWORD="${KOPIA_PASSWORD:-}"
+fi
+
+command -v "$KOPIA" >/dev/null 2>&1 || die "Kopia not found: $KOPIA"
+command -v docker   >/dev/null 2>&1 || die "Docker not found — run this repo's post-install (base + require_docker) on this box first."
+
+ACTUAL_USER="${SUDO_USER:-${USER:-$(id -un)}}"
+ACTUAL_HOME="$(getent passwd "$ACTUAL_USER" 2>/dev/null | cut -d: -f6 || echo "/home/$ACTUAL_USER")"
+DOCKER_BASE="$ACTUAL_HOME/docker"
+
+# ── Args ──────────────────────────────────────────────────────────────────────
+DO_LIST=false DRY=false START=true ONLY_SVC=""
+while [ $# -gt 0 ]; do
+    case "$1" in
+        --list)     DO_LIST=true; shift ;;
+        --dry-run)  DRY=true; shift ;;
+        --no-start) START=false; shift ;;
+        --service)  ONLY_SVC="${2:-}"; shift 2 ;;
+        *)          die "Unknown argument: $1 (see --help by reading the script header)" ;;
+    esac
+done
+
+# Bounded so a stalled repo connection (offsite mirror host unreachable
+# mid-restore, etc.) can't hang forever and block every service behind it in
+# the batch — 300s is generous for this stack's data sizes; raise it if a
+# service's dataset genuinely needs longer.
+k_for() {
+    local dest="$1"; shift
+    local cfg_var="DEST_${dest}_CONFIG" pw_var="DEST_${dest}_PASSWORD"
+    local cfg="${!cfg_var:-}" pw="${!pw_var:-}"
+    [ -n "$cfg" ] || return 1
+    timeout 300 env KOPIA_PASSWORD="$pw" "$KOPIA" --config-file="$cfg" "$@"
+}
+
+# ── Discover the latest restorable snapshot per service, across every
+# destination — no dependency on backup.conf's SVC_<name> map, which only
+# says where a *new* backup should go, not where past snapshots actually
+# landed (relevant if a service was ever reassigned between destinations).
+read -ra _DEST_ARR <<< "$DEST_NAMES"
+declare -a SRC_PATH_LIST=() SRC_DEST_LIST=() SRC_SNAP_LIST=()
+
+for dest in "${_DEST_ARR[@]}"; do
+    if ! k_for "$dest" repository status >/dev/null 2>&1; then
+        warn "Cannot connect to destination '$dest' — skipping."
+        continue
+    fi
+    SNAP_JSON="$(k_for "$dest" snapshot list --all --json 2>/dev/null)"
+    [ -z "$SNAP_JSON" ] && continue
+    [ "$SNAP_JSON" = "null" ] && continue
+
+    mapfile -t _paths < <(echo "$SNAP_JSON" | jq -r --arg base "$DOCKER_BASE/" \
+        '[.[] | select(.source.path | startswith($base))] | group_by(.source.path)[] | .[0].source.path')
+
+    for p in "${_paths[@]}"; do
+        svc="$(basename "$p")"
+        [ -n "$ONLY_SVC" ] && [ "$svc" != "$ONLY_SVC" ] && continue
+
+        # First destination to claim a service name wins (DEST_NAMES always
+        # lists "default" first — see backup.sh) so a stale duplicate in a
+        # second repo can't shadow the current one.
+        _dupe=false
+        for _seen in "${SRC_PATH_LIST[@]:-}"; do
+            [ "$(basename "$_seen")" = "$svc" ] && _dupe=true && break
+        done
+        [ "$_dupe" = true ] && continue
+
+        latest_id="$(echo "$SNAP_JSON" | jq -r --arg p "$p" \
+            '[.[] | select(.source.path == $p)] | sort_by(.startTime) | reverse | .[0].id')"
+        [ -z "$latest_id" ] && continue
+        [ "$latest_id" = "null" ] && continue
+
+        SRC_PATH_LIST+=("$p")
+        SRC_DEST_LIST+=("$dest")
+        SRC_SNAP_LIST+=("$latest_id")
+    done
+done
+
+echo ""
+echo "╔═══════════════════════════════════════════════════════╗"
+echo "║   Kopia Disaster-Recovery Bring-Up                     ║"
+echo "╚═══════════════════════════════════════════════════════╝"
+
+if [ "$DO_LIST" = true ]; then
+    echo ""
+    [ "${#SRC_PATH_LIST[@]}" -eq 0 ] && { warn "No restorable sources found."; exit 0; }
+    printf "  %-16s  %-10s  %s\n" "SERVICE" "DEST" "PATH"
+    for i in "${!SRC_PATH_LIST[@]}"; do
+        printf "  %-16s  %-10s  %s\n" "$(basename "${SRC_PATH_LIST[$i]}")" "${SRC_DEST_LIST[$i]}" "${SRC_PATH_LIST[$i]}"
+    done
+    exit 0
+fi
+
+if [ "${#SRC_PATH_LIST[@]}" -eq 0 ]; then
+    if [ -n "$ONLY_SVC" ]; then
+        die "No snapshots found for service '$ONLY_SVC'."
+    else
+        die "No snapshots found. Run a backup on the primary box first, then copy backup.conf here."
+    fi
+fi
+
+# ── Restore + start ───────────────────────────────────────────────────────────
+TOTAL_START=$(date +%s)
+declare -a UP_SVCS=() FAILED_SVCS=()
+
+for i in "${!SRC_PATH_LIST[@]}"; do
+    path="${SRC_PATH_LIST[$i]}"
+    dest="${SRC_DEST_LIST[$i]}"
+    snap="${SRC_SNAP_LIST[$i]}"
+    svc="$(basename "$path")"
+    compose="${path%/}/docker-compose.yml"
+
+    echo ""
+    info "── $svc (dest: $dest, snapshot: ${snap:0:12}...) ──"
+
+    if [ "$DRY" = true ]; then
+        echo "    [DRY-RUN] Would restore → $path"
+        [ "$START" = true ] && echo "    [DRY-RUN] Would run: docker compose -f $compose up -d"
+        continue
+    fi
+
+    SVC_START=$(date +%s)
+
+    if [ -e "$path" ]; then
+        aside="${path%/}.pre-dr-$(date +%Y%m%d-%H%M%S)"
+        mv "$path" "$aside"
+        info "  Existing data moved aside → $(basename "$aside")"
+    fi
+    mkdir -p "$path"
+
+    if ! k_for "$dest" restore "$snap" "$path"; then
+        err "  Restore failed (or timed out) for $svc"
+        FAILED_SVCS+=("$svc: restore failed or timed out")
+        continue
+    fi
+    chown -R "$ACTUAL_USER:$ACTUAL_USER" "$path" 2>/dev/null || true
+    ok "  Restored"
+
+    if [ "$START" = true ]; then
+        if [ ! -f "$compose" ]; then
+            warn "  No docker-compose.yml at $path — restored but not started"
+            FAILED_SVCS+=("$svc: no compose file")
+            continue
+        fi
+        # Bounded so a stuck image pull or a compose file waiting on something
+        # (e.g. an interactive prompt) can't stall the rest of the batch — one
+        # bad service should never cost the others their spot in the 10-minute
+        # budget this script exists for.
+        if timeout 120 docker compose -f "$compose" up -d 2>/dev/null; then
+            ok "  Started"
+        else
+            err "  docker compose up -d failed (or timed out) for $svc"
+            FAILED_SVCS+=("$svc: compose up failed or timed out")
+            continue
+        fi
+    fi
+
+    SVC_ELAPSED=$(( $(date +%s) - SVC_START ))
+    UP_SVCS+=("$svc (${SVC_ELAPSED}s)")
+done
+
+TOTAL_ELAPSED=$(( $(date +%s) - TOTAL_START ))
+
+echo ""
+echo "═══════════════════════════════════════════════════════"
+if [ "$DRY" = true ]; then
+    echo "  DRY-RUN COMPLETE — nothing was touched"
+else
+    echo "  DISASTER-RECOVERY BRING-UP COMPLETE"
+fi
+echo "═══════════════════════════════════════════════════════"
+echo ""
+[ "$DRY" = false ] && echo "  Total time: $((TOTAL_ELAPSED/60))m $((TOTAL_ELAPSED%60))s" && echo ""
+
+if [ "${#UP_SVCS[@]}" -gt 0 ]; then
+    echo "  Up:"
+    for s in "${UP_SVCS[@]}"; do echo "    ✓ $s"; done
+    echo ""
+fi
+
+if [ "${#FAILED_SVCS[@]}" -gt 0 ]; then
+    echo "  Failed (skipped — did not stop the rest of the batch):"
+    for s in "${FAILED_SVCS[@]}"; do echo "    ✗ $s"; done
+    echo ""
+fi
+
+# One bad service is a partial success, not a failed run — the whole point of
+# this script is getting as much of the stack back up as possible. Only a
+# fully empty result (nothing came up at all) counts as a failed exit code.
+if [ "$DRY" = false ] && [ "${#UP_SVCS[@]}" -eq 0 ]; then
+    err "Nothing came up."
+    exit 1
+fi
+
+exit 0
diff --git a/lib/common.sh b/lib/common.sh
index b8b8209..3eb0ef3 100644
--- a/lib/common.sh
+++ b/lib/common.sh
@@ -698,3 +698,82 @@ CADDY_BLOCK
     fi
     echo ""
 }
+
+# ── Shared coturn (TURN/STUN) wiring ──────────────────────────────────────────
+# Usage: ensure_coturn_user "<consumer-name>"
+#
+# Installs the shared coturn service (services/coturn.sh) if this is the
+# first service on the box that needs TURN, then registers (or reuses) a
+# dedicated long-term-credential user for the caller — one coturn instance,
+# one relay port range, shared by every consumer instead of each service
+# running its own and fighting over host ports (see services/coturn.sh's
+# header for why that used to be a real, confirmed-live problem).
+#
+# Out-params (not `local` — read them after the call returns), same
+# convention as configure_caddy_for_service's CADDY_SERVICE_* above:
+#   COTURN_HOST      host/IP TURN clients should connect to
+#   COTURN_PORT      coturn's listening port
+#   COTURN_USERNAME  this consumer's long-term-credential username
+#   COTURN_PASSWORD  this consumer's long-term-credential password
+# COTURN_HOST is left empty if coturn couldn't be installed or reached —
+# callers should treat that as "no TURN available" and degrade gracefully,
+# same as checking CADDY_SERVICE_CONFIGURED after configure_caddy_for_service.
+#
+# Credentials are cached per-consumer in coturn's own users/<name>.env so a
+# service re-running its own installer reuses the same one instead of
+# minting a new credential and orphaning the old one (which would silently
+# break already-configured clients still holding it).
+ensure_coturn_user() {
+    local _consumer="$1"
+    COTURN_HOST="" COTURN_PORT="" COTURN_USERNAME="" COTURN_PASSWORD=""
+
+    if [ ! -d "$DOCKER_DIR/coturn" ]; then
+        if declare -F install_coturn >/dev/null 2>&1; then
+            log_info "No shared coturn (TURN/STUN) server yet — setting one up for $_consumer..."
+            install_coturn || { log_warning "coturn setup failed — $_consumer will run without TURN."; return 1; }
+        else
+            log_warning "services/coturn.sh not loaded — $_consumer will run without TURN."
+            log_warning "Run: sudo ./setup.sh coturn"
+            return 1
+        fi
+    fi
+
+    if [ "$DRY_RUN" = true ]; then
+        echo "[DRY-RUN] Would register coturn user '$_consumer'"
+        return 0
+    fi
+
+    local _env="$DOCKER_DIR/coturn/.env"
+    [ -f "$_env" ] || { log_warning "coturn installed but $_env missing — cannot register '$_consumer'."; return 1; }
+    local _realm _host _port
+    _realm="$(grep '^COTURN_REALM=' "$_env" | cut -d= -f2-)"
+    _host="$(grep '^COTURN_HOST=' "$_env" | cut -d= -f2-)"
+    _port="$(grep '^COTURN_PORT=' "$_env" | cut -d= -f2-)"; _port="${_port:-3478}"
+
+    local _userdir="$DOCKER_DIR/coturn/users"
+    local _userfile="$_userdir/${_consumer}.env"
+    mkdir -p "$_userdir"
+
+    if [ -f "$_userfile" ]; then
+        local _u _p
+        _u="$(grep '^COTURN_USER=' "$_userfile" | cut -d= -f2-)"
+        _p="$(grep '^COTURN_PASS=' "$_userfile" | cut -d= -f2-)"
+        COTURN_USERNAME="$_u" COTURN_PASSWORD="$_p"
+    else
+        COTURN_USERNAME="$_consumer"
+        COTURN_PASSWORD="$(generate_password 24)"
+        if docker exec coturn turnadmin -a -u "$COTURN_USERNAME" -p "$COTURN_PASSWORD" \
+            -r "$_realm" -b /var/lib/coturn/turndb >/dev/null 2>&1; then
+            { echo "COTURN_USER=$COTURN_USERNAME"; echo "COTURN_PASS=$COTURN_PASSWORD"; } > "$_userfile"
+            chmod 600 "$_userfile"
+            log_success "Registered coturn user '$COTURN_USERNAME' for $_consumer"
+        else
+            log_warning "Could not register a coturn user for $_consumer — is the coturn container running?"
+            COTURN_USERNAME="" COTURN_PASSWORD=""
+            return 1
+        fi
+    fi
+
+    COTURN_HOST="$_host"
+    COTURN_PORT="$_port"
+}
diff --git a/services/asterisk.sh b/services/asterisk.sh
index 019ea2b..ac5cf06 100644
--- a/services/asterisk.sh
+++ b/services/asterisk.sh
@@ -232,7 +232,7 @@ CBLOCK
 fi
 # ─────────────────────────────────────────────────────────────────────────────
 
-register_service asterisk homelab "Easy Asterisk PBX + coturn TURN server (intercom/VoIP; auto-tunes for a DigitalOcean droplet)" 5061
+register_service asterisk homelab "Easy Asterisk PBX (intercom/VoIP; auto-tunes for a DigitalOcean droplet); TURN via the shared coturn service" 5061
 
 # ── Install layout: directory + container names ────────────────────────────
 # Sets ASTERISK_DIR / ASTERISK_CONTAINER / ASTERISK_COTURN / ASTERISK_PROJECT.
@@ -795,9 +795,52 @@ _asterisk_offer_dashboard_and_trunk() {
 # literally (it interpolates them from .env, this script must not). Project
 # and container names are therefore substituted afterwards, same placeholder
 # trick the Caddy volume line already uses below.
+#
+# USE_EMBEDDED_COTURN controls whether this install runs its own dedicated
+# coturn container (legacy shape) or relies on the shared coturn service
+# (services/coturn.sh) instead. This is NOT a free choice at every call site
+# — an install that already has its own embedded coturn must keep getting
+# one on every "update" regeneration of this file, or the next `docker
+# compose up` silently drops the container its own .env TURN_PASSWORD still
+# points at, breaking every already-configured phone with no warning. See
+# the two call sites below for how each decides.
 _asterisk_write_compose() {
-    local PROJECT="$1" CONTAINER="$2" COTURN_CONTAINER="$3"
-    cat > docker-compose.yml << 'EOF'
+    local PROJECT="$1" CONTAINER="$2" COTURN_CONTAINER="$3" USE_EMBEDDED_COTURN="${4:-true}"
+
+    local _COTURN_DEPENDS="    depends_on:
+      coturn:
+        condition: service_started
+"
+    local _COTURN_SERVICE="
+  coturn:
+    image: coturn/coturn:latest
+    container_name: COTURN_CONTAINER_PLACEHOLDER
+    network_mode: host
+    user: root
+    entrypoint: [\"/coturn-entrypoint.sh\"]
+    volumes:
+      - ./docker/coturn-entrypoint.sh:/coturn-entrypoint.sh:ro
+    env_file: .env
+    command:
+      - -n
+      - --listening-port=\${TURN_PORT:-3478}
+      - --listening-ip=0.0.0.0
+      - --fingerprint
+      - --lt-cred-mech
+      - --user=\${TURN_USERNAME:-easyasterisk}:\${TURN_PASSWORD}
+      - --realm=\${DOMAIN_NAME:-localhost}
+      - --min-port=49152
+      - --max-port=49252
+      - --no-tls
+      - --no-dtls
+      - --no-cli
+      - --no-multicast-peers
+      - --log-file=stdout
+    restart: unless-stopped
+"
+    [[ "$USE_EMBEDDED_COTURN" != true ]] && _COTURN_DEPENDS="" && _COTURN_SERVICE=""
+
+    cat > docker-compose.yml << EOF
 name: PROJECT_NAME_PLACEHOLDER
 
 services:
@@ -805,10 +848,7 @@ services:
     build: .
     container_name: ASTERISK_CONTAINER_PLACEHOLDER
     network_mode: host
-    depends_on:
-      coturn:
-        condition: service_started
-    volumes:
+${_COTURN_DEPENDS}    volumes:
       - ./config/asterisk:/etc/asterisk
       - ./config/easy-asterisk:/etc/easy-asterisk
       - ./logs:/var/log/asterisk
@@ -824,33 +864,7 @@ CADDY_VOLUME_PLACEHOLDER
       interval: 30s
       timeout: 5s
       retries: 3
-
-  coturn:
-    image: coturn/coturn:latest
-    container_name: COTURN_CONTAINER_PLACEHOLDER
-    network_mode: host
-    user: root
-    entrypoint: ["/coturn-entrypoint.sh"]
-    volumes:
-      - ./docker/coturn-entrypoint.sh:/coturn-entrypoint.sh:ro
-    env_file: .env
-    command:
-      - -n
-      - --listening-port=${TURN_PORT:-3478}
-      - --listening-ip=0.0.0.0
-      - --fingerprint
-      - --lt-cred-mech
-      - --user=${TURN_USERNAME:-easyasterisk}:${TURN_PASSWORD}
-      - --realm=${DOMAIN_NAME:-localhost}
-      - --min-port=49152
-      - --max-port=49252
-      - --no-tls
-      - --no-dtls
-      - --no-cli
-      - --no-multicast-peers
-      - --log-file=stdout
-    restart: unless-stopped
-
+${_COTURN_SERVICE}
 EOF
 
     sed -i "s#PROJECT_NAME_PLACEHOLDER#${PROJECT}#; \
@@ -859,8 +873,10 @@ EOF
 
     # Share Caddy's cert store (read-only) so the entrypoint can auto-sync a
     # real Let's Encrypt cert for DOMAIN_NAME instead of falling back to
-    # self-signed. No-op if Caddy isn't installed on this box.
-    if [[ -d "$DOCKER_DIR/caddy/data" ]]; then
+    # self-signed. No-op if Caddy isn't installed on this box. Only relevant
+    # to the embedded coturn — the shared coturn service doesn't do TLS/TURNS
+    # at all (see services/coturn.sh's README for that tradeoff).
+    if [[ "$USE_EMBEDDED_COTURN" == true && -d "$DOCKER_DIR/caddy/data" ]]; then
         sed -i "s#CADDY_VOLUME_PLACEHOLDER#      - ${DOCKER_DIR}/caddy/data:/caddy-data:ro#" docker-compose.yml
     else
         sed -i "/CADDY_VOLUME_PLACEHOLDER/d" docker-compose.yml
@@ -1145,7 +1161,9 @@ _asterisk_configure_do_cloud_firewall() {
 # the two deployment shapes can't document themselves differently by accident.
 _asterisk_write_readme() {
     local EA_DIR="$1" CONTAINER="$2" IS_DO="$3" DOMAIN_NAME="$4" PUBLIC_IP="$5" WEB_ADMIN_PORT_VAL="$6"
+    local USE_EMBEDDED_COTURN="${7:-true}" TURN_USERNAME_VAL="${8:-easyasterisk}" TURN_SERVER_DISPLAY="${9:-}"
     local _host="${DOMAIN_NAME:-${PUBLIC_IP:-<host-ip>}}"
+    [ -z "$TURN_SERVER_DISPLAY" ] && TURN_SERVER_DISPLAY="${_host}:3478"
 
     {
         cat << MD
@@ -1186,10 +1204,14 @@ connecting a phone. The Security Dashboard's Extensions tab
 |-----------------|--------------------------------------|
 | SIP server      | \`${_host}\`                          |
 | SIP port        | 5061 (TLS) / 5060 (UDP)              |
-| TURN server     | \`${_host}:3478\`                     |
-| TURN username   | easyasterisk                         |
+| TURN server     | \`${TURN_SERVER_DISPLAY}\`            |
+| TURN username   | ${TURN_USERNAME_VAL}                 |
 | TURN password   | see \`.env\` → \`TURN_PASSWORD\`         |
 
+$( [[ "$USE_EMBEDDED_COTURN" == true ]] \
+    && echo "This install runs its own dedicated coturn container (the \`coturn:\` service in docker-compose.yml)." \
+    || echo "TURN is served by the box's shared coturn service, not a container in this compose file — see \`~/docker/coturn/README.md\`. Every service on the box that needs TURN (Mattermost Calls, etc.) shares this same relay, each with its own dedicated username." )
+
 Recommended softphones: Linphone, Zoiper, Bria, Grandstream Wave, and
 [Sipnetic](https://www.sipnetic.com/) on Android (free, TLS/SRTP +
 STUN/TURN/ICE). For a phone to work the same way regardless of network (LAN,
@@ -1403,7 +1425,11 @@ install_asterisk() {
         echo "[DRY-RUN]     - offer local OR remote Authelia to protect the web admin"
         echo "[DRY-RUN]     - offer to create a DigitalOcean Cloud Firewall via doctl"
         echo "[DRY-RUN] Would scan for a free web admin port starting at 8081 (avoids e.g. CrowdSec's 8080)"
-        echo "[DRY-RUN] Would open UFW ports: 5060, 5061, <web admin port>, 8088, 8089, 3478, 10000-20000, 49152-49252"
+        echo "[DRY-RUN] Would register a TURN user with the shared coturn service (chain-installing it"
+        echo "[DRY-RUN]   if this is the first service on the box that needs one), falling back to"
+        echo "[DRY-RUN]   Asterisk's own dedicated coturn if the shared service is unavailable"
+        echo "[DRY-RUN] Would open UFW ports: 5060, 5061, <web admin port>, 8088, 8089, 10000-20000,"
+        echo "[DRY-RUN]   plus 3478 + 49152-49252 only if falling back to a dedicated coturn"
         echo "[DRY-RUN] Would offer 'update in place' instead of a fresh install if $EA_DIR already exists"
         echo "[DRY-RUN] Would patch vendor device-creation code + extensions.conf generator to route"
         echo "[DRY-RUN]   internal SIP MESSAGE through a dedicated [sip-messaging] dialplan context,"
@@ -1434,13 +1460,24 @@ install_asterisk() {
         prompt_reinstall_mode REINSTALL_MODE
         case "$REINSTALL_MODE" in
             update)
+                # Detect BEFORE regenerating docker-compose.yml below: an
+                # install that already runs its own dedicated coturn (every
+                # install predating the shared coturn service) must keep
+                # getting one on every update, or this rebuild silently
+                # drops the container its own .env TURN_PASSWORD still
+                # points at — every already-configured phone loses TURN with
+                # no warning. Only an install with no embedded coturn block
+                # (new installs made after shared coturn existed) skips it.
+                local _HAD_EMBEDDED_COTURN=false
+                grep -q '^  coturn:' "$EA_DIR/docker-compose.yml" 2>/dev/null && _HAD_EMBEDDED_COTURN=true
+
                 mkdir -p "$EA_DIR/config/asterisk" "$EA_DIR/config/easy-asterisk" \
                          "$EA_DIR/logs" "$EA_DIR/spool" "$EA_DIR/lib" "$EA_DIR/exports"
                 ensure_docker_dir_ownership "$EA_DIR"
                 cd "$EA_DIR" || return 1
 
                 _asterisk_refresh_vendor_files
-                _asterisk_write_compose "$ASTERISK_PROJECT" "$CONTAINER" "$ASTERISK_COTURN"
+                _asterisk_write_compose "$ASTERISK_PROJECT" "$CONTAINER" "$ASTERISK_COTURN" "$_HAD_EMBEDDED_COTURN"
                 _asterisk_write_logrotate "$EA_DIR"
                 _asterisk_patch_messaging_vendor_files "$EA_DIR"
                 _asterisk_write_messaging_dialplan "$EA_DIR/config/asterisk/messaging-dialplan.conf"
@@ -1559,21 +1596,53 @@ install_asterisk() {
         [[ -n "$VLAN_SUBNETS_VAL" ]] && HAS_VLANS_VAL="y"
     fi
 
-    # ── Secrets ───────────────────────────────────────────────────────────────
-    local TURN_PASSWORD
-    TURN_PASSWORD="$(generate_password 24)"
+    # ── Secrets / TURN ───────────────────────────────────────────────────────
+    # Prefer the shared coturn service (services/coturn.sh) — one TURN server
+    # for every service on the box instead of Asterisk running its own and
+    # fighting other consumers (Mattermost, etc.) over relay ports. Falls
+    # back to Asterisk's own dedicated coturn if the shared service isn't
+    # available (e.g. this file run standalone with no sibling services/*.sh
+    # sourced) or registration fails for any reason — Asterisk should never
+    # end up with no TURN at all just because the shared path had a problem.
+    local USE_EMBEDDED_COTURN=true
+    local TURN_USERNAME TURN_PASSWORD TURN_PORT_VAL TURN_SERVER_VAL
 
-    # A public box always has a usable TURN address (the FQDN if set, else its
-    # public IP). A LAN box with no FQDN has none — coturn is only reachable
-    # over the local network, so clients use the server's LAN address directly.
-    local TURN_SERVER_VAL=""
-    if [[ "$IS_DO" == true ]]; then
-        TURN_SERVER_VAL="${DOMAIN_NAME:-$PUBLIC_IP}:3478"
-    elif [[ -n "$DOMAIN_NAME" ]]; then
-        TURN_SERVER_VAL="${DOMAIN_NAME}:3478"
+    # Only reachable here via an explicit "fresh" choice above — "update"
+    # is handled separately and always preserves whatever coturn shape
+    # already exists, never silently switches it.
+    if [[ -f "$EA_DIR/docker-compose.yml" ]] && grep -q '^  coturn:' "$EA_DIR/docker-compose.yml" 2>/dev/null; then
+        echo ""
+        log_warning "This box's existing Asterisk install has its own dedicated coturn."
+        log_warning "Continuing may switch it to the new shared coturn service — any"
+        log_warning "phone/softphone configured with the OLD TURN username/password will"
+        log_warning "need updating once this completes."
     fi
 
-    _asterisk_write_compose "$ASTERISK_PROJECT" "$CONTAINER" "$ASTERISK_COTURN"
+    ensure_coturn_user "asterisk"
+    if [[ -n "${COTURN_HOST:-}" ]]; then
+        USE_EMBEDDED_COTURN=false
+        TURN_USERNAME="$COTURN_USERNAME"
+        TURN_PASSWORD="$COTURN_PASSWORD"
+        TURN_PORT_VAL="$COTURN_PORT"
+        TURN_SERVER_VAL="${COTURN_HOST}:${COTURN_PORT}"
+        log_success "Using the shared coturn service — TURN username '$COTURN_USERNAME'."
+    else
+        TURN_USERNAME="easyasterisk"
+        TURN_PASSWORD="$(generate_password 24)"
+        TURN_PORT_VAL="3478"
+        # A public box always has a usable TURN address (the FQDN if set, else its
+        # public IP). A LAN box with no FQDN has none — coturn is only reachable
+        # over the local network, so clients use the server's LAN address directly.
+        TURN_SERVER_VAL=""
+        if [[ "$IS_DO" == true ]]; then
+            TURN_SERVER_VAL="${DOMAIN_NAME:-$PUBLIC_IP}:3478"
+        elif [[ -n "$DOMAIN_NAME" ]]; then
+            TURN_SERVER_VAL="${DOMAIN_NAME}:3478"
+        fi
+        log_info "Shared coturn unavailable — Asterisk will run its own dedicated coturn."
+    fi
+
+    _asterisk_write_compose "$ASTERISK_PROJECT" "$CONTAINER" "$ASTERISK_COTURN" "$USE_EMBEDDED_COTURN"
 
     # ── Pick a free port for the web admin ─────────────────────────────────────
     # Hardcoding a single number gets fragile fast once several services share
@@ -1612,9 +1681,10 @@ install_asterisk() {
 DOMAIN_NAME=${DOMAIN_NAME}
 
 # ── TURN/STUN ─────────────────────────────────────────────────
-TURN_USERNAME=easyasterisk
+# $( [[ "$USE_EMBEDDED_COTURN" == true ]] && echo "This install runs its own dedicated coturn (see the coturn: service in docker-compose.yml)." || echo "Using the shared coturn service — see ~/docker/coturn/README.md." )
+TURN_USERNAME=${TURN_USERNAME}
 TURN_PASSWORD=${TURN_PASSWORD}
-TURN_PORT=3478
+TURN_PORT=${TURN_PORT_VAL}
 # Empty when there's no publicly resolvable address (LAN-only, no FQDN).
 TURN_SERVER=${TURN_SERVER_VAL}
 
@@ -1679,10 +1749,14 @@ ENV
         fi
         ufw allow 8088/tcp
         ufw allow 8089/tcp
-        ufw allow 3478/udp
-        ufw allow 3478/tcp
         ufw allow 10000:20000/udp
-        ufw allow 49152:49252/udp
+        if [[ "$USE_EMBEDDED_COTURN" == true ]]; then
+            ufw allow 3478/udp
+            ufw allow 3478/tcp
+            ufw allow 49152:49252/udp
+        fi
+        # Shared coturn opens its own ports once, at its own install time
+        # (services/coturn.sh) — nothing to open here when using it.
         ensure_ufw_enabled
         log_success "UFW rules added."
     fi
@@ -1713,7 +1787,8 @@ ENV
     _asterisk_run_presence_step "$EA_DIR" "$CONTAINER"
 
     # ── README ────────────────────────────────────────────────────────────────
-    _asterisk_write_readme "$EA_DIR" "$CONTAINER" "$IS_DO" "$DOMAIN_NAME" "$PUBLIC_IP" "$WEB_ADMIN_PORT_VAL"
+    _asterisk_write_readme "$EA_DIR" "$CONTAINER" "$IS_DO" "$DOMAIN_NAME" "$PUBLIC_IP" "$WEB_ADMIN_PORT_VAL" \
+        "$USE_EMBEDDED_COTURN" "$TURN_USERNAME" "$TURN_SERVER_VAL"
 
     # ── Start ─────────────────────────────────────────────────────────────────
     echo ""
diff --git a/services/backup.sh b/services/backup.sh
index 23f5a84..c32b388 100644
--- a/services/backup.sh
+++ b/services/backup.sh
@@ -214,6 +214,7 @@ install_backup() {
     local CONF_FILE="$DIR/backup.conf"
     local WORKER="$DIR/backup_kopia.sh"
     local RESTORE="$DIR/restore_kopia.sh"
+    local DR_BRINGUP="$DIR/dr_bringup.sh"
     local SVC_NAME="post-install-backup"
 
     echo ""
@@ -451,6 +452,40 @@ install_backup() {
     if [ -n "$NTFY_URL" ]; then
         prompt_text "  ntfy access token (blank if public/no auth):" "" NTFY_TOKEN
     fi
+
+    # ── Disaster-recovery spare box (optional) ────────────────────────────────
+    echo ""
+    echo "═══════════════════════════════════════════════════════"
+    echo "  DISASTER-RECOVERY SPARE (optional)"
+    echo "═══════════════════════════════════════════════════════"
+    echo ""
+    echo "  If you keep a spare box ready to take over on failure (running"
+    echo "  dr_bringup.sh), this can push backup.conf + README.md to it after"
+    echo "  every successful backup, so it's always ready without a manual copy."
+    echo ""
+    echo "  Requires passwordless SSH (key-based) from THIS box to the spare,"
+    echo "  as the account below. Since the backup timer runs as root, that"
+    echo "  usually means a key in /root/.ssh authorized on the spare — set that"
+    echo "  up first if you haven't (ssh-keygen, then ssh-copy-id to the spare)."
+    echo ""
+    local DR_SYNC_HOST="" DR_SYNC_PATH=""
+    prompt_text "  Spare box SSH destination, user@host (blank to skip):" "" DR_SYNC_HOST
+    if [ -n "$DR_SYNC_HOST" ]; then
+        prompt_text "  Path for backup.conf/README on the spare:" "~/docker/backup" DR_SYNC_PATH
+        DR_SYNC_PATH="${DR_SYNC_PATH:-~/docker/backup}"
+
+        # Catch a missing/unauthorized key now, not at 2am during the first
+        # scheduled backup. Non-fatal either way — the setting is saved
+        # regardless, since the key may simply not be set up yet.
+        if ssh -o BatchMode=yes -o ConnectTimeout=5 "$DR_SYNC_HOST" true 2>/dev/null; then
+            log_success "  SSH to $DR_SYNC_HOST works — spare sync will run after each backup."
+        else
+            log_warning "  Couldn't SSH to $DR_SYNC_HOST without a password right now."
+            log_warning "  Spare sync is saved but will fail until this works (as root, since"
+            log_warning "  the backup timer runs as root): ssh-keygen; ssh-copy-id $DR_SYNC_HOST"
+        fi
+    fi
+
     mkdir -p "$DIR"
     ensure_docker_dir_ownership "$DIR"
 
@@ -530,6 +565,14 @@ install_backup() {
         echo "# Leave blank to disable. NTFY_TOKEN is optional (for private topics)."
         printf "NTFY_URL='%s'\n" "${NTFY_URL:-}"
         printf "NTFY_TOKEN='%s'\n" "${NTFY_TOKEN:-}"
+        echo ""
+        echo "# ── Disaster-recovery spare sync ───────────────────────────────────────────"
+        echo "# If set, backup_kopia.sh scp's this backup.conf + README.md to"
+        echo "# DR_SYNC_HOST:DR_SYNC_PATH after every successful backup, so a spare box"
+        echo "# running dr_bringup.sh is always ready with no manual copy step. Requires"
+        echo "# passwordless SSH from this box to the spare (see README.md)."
+        printf "DR_SYNC_HOST='%s'\n" "${DR_SYNC_HOST:-}"
+        printf "DR_SYNC_PATH='%s'\n" "${DR_SYNC_PATH:-~/docker/backup}"
     } > "$CONF_FILE"
     chown root:root "$CONF_FILE" 2>/dev/null || true
     chmod 600 "$CONF_FILE"
@@ -554,6 +597,21 @@ install_backup() {
         log_warning "Copy it manually: cp extras/restore_kopia.sh $RESTORE"
     fi
 
+    # ── 10b. Install disaster-recovery bring-up script ────────────────────────
+    # Non-interactive counterpart to restore_kopia.sh: restores every service's
+    # latest snapshot and runs `docker compose up -d` with no prompts, meant to
+    # run on a cold spare box during a real outage rather than the primary.
+    local DR_BRINGUP_SRC="${HERE:-}/extras/dr_bringup_kopia.sh"
+    if [ -f "$DR_BRINGUP_SRC" ]; then
+        cp "$DR_BRINGUP_SRC" "$DR_BRINGUP"
+        chmod +x "$DR_BRINGUP"
+        chown root:root "$DR_BRINGUP" 2>/dev/null || true
+        log_success "dr_bringup.sh installed"
+    else
+        log_warning "extras/dr_bringup_kopia.sh not found — DR bring-up script not installed"
+        log_warning "Copy it manually: cp extras/dr_bringup_kopia.sh $DR_BRINGUP"
+    fi
+
     # ── 11. Install test scripts ─────────────────────────────────────────────
     local TEST_SCRIPT="$DIR/test_backup_kopia.sh"
     local TEST_SRC="${HERE:-}/extras/test_backup_kopia.sh"
@@ -660,6 +718,106 @@ SVCEOF
         AUTORUN="cat /etc/cron.d/${SVC_NAME}"
     fi
 
+    # ── Write README ─────────────────────────────────────────────────────────
+    # Written before the optional first run below so, if DR sync is enabled,
+    # the very first backup already ships an up-to-date README to the spare.
+    local DEST_LIST_MD=""
+    for dn in "${DEST_NAMES_ARR[@]}"; do
+        DEST_LIST_MD+="- **${dn}**: ${DEST_REPOS[$dn]}"$'\n'
+    done
+
+    local DR_SYNC_MD OFFSITE_MD
+    if [ -n "${DR_SYNC_HOST:-}" ]; then
+        DR_SYNC_MD="Configured: after every successful backup, this box copies backup.conf + this README to \`${DR_SYNC_HOST}:${DR_SYNC_PATH:-~/docker/backup}\` over SSH."
+    else
+        DR_SYNC_MD="Not configured. Re-run this installer to set it up, or copy backup.conf to the spare manually whenever it changes."
+    fi
+    if [ "${REMOTE_TYPE:-none}" != "none" ]; then
+        OFFSITE_MD="Configured: every backup also runs \`kopia repository sync-to ${REMOTE_TYPE}\` to mirror the repo off this box."
+    else
+        OFFSITE_MD="Not configured. Set REMOTE_TYPE/REMOTE_ARGS in backup.conf (see the comment above them) to mirror the repo off this box."
+    fi
+
+    write_readme "$DIR" << MD
+# Backup — Kopia
+
+Full recovery for every Docker service under \`$DOCKER_DIR\`: each service's
+entire directory (compose file, \`.env\`, config, data, databases) is
+snapshotted with Kopia — deduplicated, compressed (zstd), and encrypted.
+Databases are captured consistently (container stopped briefly, snapshotted,
+restarted); Minecraft instead gets a live save-all flush, no downtime.
+
+## Destinations
+
+$DEST_LIST_MD
+## Schedule
+
+$SCHED_LABEL — keeps the latest $KEEP_LATEST snapshots (plus 7 daily / 4
+weekly / 3 monthly).
+
+## Commands
+
+\`\`\`bash
+sudo $WORKER                     # back up now
+sudo $WORKER snapshots           # list all snapshots
+sudo $WORKER policy              # show retention policy
+\`\`\`
+
+### Restore — interactive, one service at a time
+
+\`\`\`bash
+sudo $RESTORE
+sudo $RESTORE --list
+\`\`\`
+
+### Disaster recovery — unattended, every service, for a cold spare box
+
+\`\`\`bash
+sudo $DR_BRINGUP                 # restore + start everything
+sudo $DR_BRINGUP --list          # list what's restorable
+sudo $DR_BRINGUP --dry-run       # preview, touch nothing
+sudo $DR_BRINGUP --service NAME  # just one service
+\`\`\`
+
+A single service failing to restore or start does not stop the rest of the
+batch — it's logged and skipped so the run maximizes what actually comes
+back up. The exit code is only non-zero if nothing came up at all.
+
+**On the spare box**, \`dr_bringup.sh\` needs \`backup.conf\` from this
+directory to connect to the repo — see the DR spare sync section below.
+
+## Disaster-recovery spare sync
+
+$DR_SYNC_MD
+
+Requires passwordless SSH (key-based) from this box to the spare — since the
+backup timer runs as root, generate/authorize a key for root:
+\`ssh-keygen\`, then \`ssh-copy-id\` to the spare.
+
+## Offsite mirror
+
+$OFFSITE_MD
+
+## Backup test — stop / restore / compare / restore-back
+
+\`\`\`bash
+sudo $TEST_SCRIPT                # test most recent backup, all services
+sudo $TEST_SCRIPT --list         # list testable services
+sudo $TEST_SCRIPT --service NAME
+\`\`\`
+
+## Files
+
+- \`backup.conf\` — destinations, passwords, retention, DR-sync/offsite settings (chmod 600)
+- \`backup_kopia.sh\` — the worker the systemd timer runs
+- \`restore_kopia.sh\` — interactive restore
+- \`dr_bringup.sh\` — unattended full-stack restore + start
+- \`test_backup_kopia.sh\` / \`test_backup.sh\` — automated restore tests
+
+**Save the passwords in \`backup.conf\` somewhere safe** — without them the
+encrypted repos cannot be restored.
+MD
+
     # ── 12. Optional first run ────────────────────────────────────────────────
     echo ""
     local _now=""
@@ -693,10 +851,24 @@ SVCEOF
     echo "    sudo $WORKER                     back up now"
     echo "    sudo $WORKER snapshots           list all snapshots"
     echo ""
-    echo "  Restore:"
+    echo "  Restore (interactive, one service at a time):"
     echo "    sudo $RESTORE"
     echo "    sudo $RESTORE --list"
     echo ""
+    echo "  Disaster recovery (unattended, every service — for a cold spare box):"
+    echo "    sudo $DR_BRINGUP              restore + start everything"
+    echo "    sudo $DR_BRINGUP --list       list what's restorable"
+    echo "    sudo $DR_BRINGUP --dry-run    preview, touch nothing"
+    if [ -n "${DR_SYNC_HOST:-}" ]; then
+        echo "    backup.conf + README.md sync to $DR_SYNC_HOST after every backup — the"
+        echo "    spare stays ready with no manual copy step."
+    else
+        echo "    Copy backup.conf to the spare box first — it holds the repo path(s)"
+        echo "    and password(s) this needs to connect."
+    fi
+    echo ""
+    echo "  Full docs: $DIR/README.md"
+    echo ""
     echo "  Backup test (stop/restore/compare/restore-back):"
     echo "    sudo $TEST_SCRIPT                test most recent backup (all services)"
     echo "    sudo $TEST_SCRIPT --list         list testable services"
diff --git a/services/coturn.sh b/services/coturn.sh
new file mode 100644
index 0000000..7b7ec33
--- /dev/null
+++ b/services/coturn.sh
@@ -0,0 +1,385 @@
+#!/bin/bash
+# services/coturn.sh — Shared TURN/STUN relay (coturn) for WebRTC-capable services.
+# Part of the modular post-install system (sourced by setup.sh).
+#
+# Can also be run standalone on any machine:
+#   sudo bash coturn.sh
+# (Docker must already be installed when run standalone)
+#
+# One coturn instance, shared by every service that needs TURN (Asterisk,
+# Mattermost, and anything added later) instead of each service running its
+# own — which used to mean N containers all on network_mode: host fighting
+# over relay port ranges (confirmed live: Asterisk's default range and
+# Mattermost's default range overlapped by ~100 ports before this existed).
+#
+# Runs in long-term-credential mode (--lt-cred-mech) with a SQLite user
+# database instead of a single static user — every consumer registers its
+# own dedicated username/password via ensure_coturn_user() (lib/common.sh),
+# so credentials are per-service and one consumer being compromised or
+# reconfigured doesn't affect any other's TURN access.
+#
+# Deliberately NOT --use-auth-secret (the HMAC/REST-API mode Mattermost's
+# Calls plugin also supports): coturn does not support both auth mechanisms
+# on one running instance at once — turning on --use-auth-secret silently
+# overrides --lt-cred-mech server-wide, which would break every
+# static-credential consumer (Asterisk's PJSIP TURN client wants a fixed
+# long-lived username/password, not a periodically-regenerated HMAC one).
+# lt-cred-mech supports any number of named users out of the box, which is
+# exactly the shared-multi-consumer shape this needs — no tradeoff either
+# way. Mattermost's Calls plugin is configured with a static username/
+# credential pair too (its "ICE Servers Configurations" field), not its
+# "TURN Static Auth Secret" field, so both consumers use the same mechanism.
+
+# ── Standalone bootstrap ──────────────────────────────────────────────────────
+# Detected when the script is executed directly rather than sourced by setup.sh.
+# Sets up helpers and globals, then defers execution until after the function
+# definition at the bottom of this file.
+if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
+    [[ "$(id -u)" == "0" ]] || { echo "Run with sudo: sudo bash $0"; exit 1; }
+
+    _SELF_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+    _COMMON="$_SELF_DIR/../lib/common.sh"
+
+    if [[ -f "$_COMMON" ]]; then
+        # Full repo present — use the real helpers (picks up ~/docker/.config too)
+        # shellcheck source=../lib/common.sh
+        source "$_COMMON"
+    else
+        # One-off copy — inline minimal stubs so the script works without the repo
+        log_info()    { echo -e "\033[0;34m[INFO]\033[0m $*"; }
+        log_success() { echo -e "\033[0;32m[OK]\033[0m $*"; }
+        log_warning() { echo -e "\033[1;33m[WARN]\033[0m $*"; }
+        log_error()   { echo -e "\033[0;31m[ERROR]\033[0m $*" >&2; }
+
+        require_docker() {
+            command -v docker &>/dev/null || {
+                log_error "Docker not found. Install it first:"
+                log_error "  curl -fsSL https://get.docker.com | sudo sh"
+                return 1
+            }
+            docker compose version &>/dev/null || {
+                log_error "Docker Compose plugin missing:"
+                log_error "  sudo apt-get install -y docker-compose-plugin"
+                return 1
+            }
+        }
+
+        ensure_docker_dir_ownership() {
+            chown -R "$ACTUAL_USER:$ACTUAL_USER" "$@" 2>/dev/null || true
+        }
+
+        # Match common.sh's eval-based pattern so local vars in install_* are set correctly
+        prompt_text() {
+            local _q="$1" _def="$2" _var="$3" _r
+            [[ "${UNATTENDED:-false}" == "true" ]] && { eval "$_var='$_def'"; return; }
+            read -r -p "  $_q " _r
+            eval "$_var='${_r:-$_def}'"
+        }
+
+        prompt_yn() {
+            local _q="$1" _def="$2" _var="$3" _r
+            [[ "${UNATTENDED:-false}" == "true" ]] && { eval "$_var='$_def'"; return; }
+            read -r -p "  $_q " _r
+            eval "$_var='${_r:-$_def}'"
+        }
+
+        prompt_reinstall_mode() {
+            local _var="$1" _r
+            if [[ "${UNATTENDED:-false}" == "true" ]]; then eval "$_var='cancel'"; return; fi
+            echo "  Existing install detected. Choose:"
+            echo "    r) Reinstall in place — refresh vendor files, keep existing settings"
+            echo "    f) Full install — re-run every prompt from scratch"
+            echo "    c) Cancel — leave everything as-is [default]"
+            read -r -p "  Choice [r/f/c, Enter=cancel]: " _r
+            case "${_r,,}" in
+                r) eval "$_var='update'" ;;
+                f) eval "$_var='fresh'" ;;
+                *) eval "$_var='cancel'" ;;
+            esac
+        }
+
+        write_readme() {
+            local _dir="$1"; shift
+            mkdir -p "$_dir"
+            cat > "$_dir/README.md"
+            chown "$ACTUAL_USER:$ACTUAL_USER" "$_dir/README.md" 2>/dev/null || true
+        }
+
+        generate_password() {
+            local _len="${1:-32}"
+            tr -dc 'A-Za-z0-9' < /dev/urandom | head -c "$_len"
+        }
+
+        ensure_ufw_enabled() {
+            command -v ufw &>/dev/null || return 0
+            [[ "${DRY_RUN:-false}" == "true" ]] && return 0
+            ufw status 2>/dev/null | grep -q "Status: active" && return 0
+            local _ssh_port
+            _ssh_port="$(grep -iE '^[[:space:]]*Port[[:space:]]+[0-9]+' /etc/ssh/sshd_config 2>/dev/null | tail -1 | awk '{print $2}')"
+            ufw allow "${_ssh_port:-22}/tcp" comment 'SSH' >/dev/null 2>&1
+            ufw --force enable >/dev/null 2>&1
+        }
+    fi
+
+    # Globals — ACTUAL_USER/ACTUAL_HOME must come before DOCKER_DIR
+    # ($HOME under sudo is /root, not the real user's home)
+    ACTUAL_USER="${ACTUAL_USER:-${SUDO_USER:-$USER}}"
+    ACTUAL_HOME="$(getent passwd "$ACTUAL_USER" 2>/dev/null | cut -d: -f6 || echo "${HOME:-/root}")"
+    DOCKER_DIR="${DOCKER_DIR:-$ACTUAL_HOME/docker}"
+    DRY_RUN="${DRY_RUN:-false}"
+    UNATTENDED="${UNATTENDED:-false}"
+    SITE_DOMAIN="${SITE_DOMAIN:-example.com}"
+
+    register_service() { :; }   # no-op — no wizard to register into
+    _RUN_STANDALONE=1
+fi
+# ─────────────────────────────────────────────────────────────────────────────
+
+register_service coturn homelab "Shared TURN/STUN relay (coturn) for Asterisk, Mattermost, and other WebRTC-capable services" 3478
+
+install_coturn() {
+    require_docker || return 1
+
+    local DIR="$DOCKER_DIR/coturn"
+    local ENV_FILE="$DIR/.env"
+
+    echo ""
+    echo "╔═══════════════════════════════════════════════════════╗"
+    echo "║   Shared coturn (TURN/STUN relay)                     ║"
+    echo "╚═══════════════════════════════════════════════════════╝"
+    echo ""
+    echo "  One TURN server, shared by every service that needs one (Asterisk,"
+    echo "  Mattermost Calls, anything added later) — each gets its own"
+    echo "  dedicated username/password, registered automatically the first"
+    echo "  time that service is installed. You normally don't run this"
+    echo "  directly; another service's installer chains into it."
+    echo ""
+
+    if [ "$DRY_RUN" = true ]; then
+        echo "[DRY-RUN] Would create $DIR with docker-compose.yml + .env"
+        echo "[DRY-RUN] Would run coturn in --lt-cred-mech mode with a SQLite user database"
+        echo "[DRY-RUN] Would open UFW: 3478/udp+tcp, and the relay port range udp"
+        return 0
+    fi
+
+    # ── Update vs. fresh reinstall ─────────────────────────────────────────────
+    # "update" only refreshes the image/compose shape — realm, host, port
+    # range, and every registered consumer's credentials are left exactly as
+    # they are. Rotating any of those here would silently break TURN for
+    # every service already relying on this instance (Asterisk phones,
+    # Mattermost Calls) without those services knowing to reconfigure.
+    local MODE="fresh"
+    if [[ -f "$DIR/docker-compose.yml" && -f "$ENV_FILE" ]]; then
+        prompt_reinstall_mode MODE
+        case "$MODE" in
+            update)
+                log_info "Refreshing the coturn image/compose only — realm, host, port range, and"
+                log_info "every registered consumer's credentials are left exactly as they are."
+                ;;
+            cancel)
+                log_info "Leaving the existing coturn install as-is."
+                return 0
+                ;;
+            fresh)
+                echo ""
+                log_warning "A full reinstall regenerates nothing destructive by itself, but if you"
+                log_warning "change the host/port/realm below, every already-registered consumer"
+                log_warning "(Asterisk, Mattermost, ...) keeps pointing at the OLD values in its own"
+                log_warning ".env until you re-run that service's installer too."
+                ;;
+        esac
+    fi
+
+    mkdir -p "$DIR/db" "$DIR/users"
+    ensure_docker_dir_ownership "$DIR"
+    cd "$DIR" || return 1
+
+    local COTURN_REALM="" COTURN_HOST="" COTURN_PORT="3478"
+    local COTURN_MIN_PORT="49152" COTURN_MAX_PORT="49452"
+
+    if [ "$MODE" = "update" ]; then
+        # shellcheck source=/dev/null
+        source "$ENV_FILE"
+    else
+        local _default_realm="${SITE_DOMAIN:-localhost}"
+        prompt_text "  Realm (usually your domain, or 'localhost' for LAN-only):" "$_default_realm" COTURN_REALM
+
+        local _detected_ip
+        _detected_ip="$(curl -fsS --max-time 3 https://ifconfig.me 2>/dev/null || hostname -I 2>/dev/null | awk '{print $1}')"
+        prompt_text "  Public hostname/IP TURN clients should connect to:" "$_detected_ip" COTURN_HOST
+
+        prompt_text "  Listening port:" "3478" COTURN_PORT
+        prompt_text "  Relay port range — min:" "49152" COTURN_MIN_PORT
+        prompt_text "  Relay port range — max (each concurrent relayed call needs ~1 port; 300 ports is generous for a homelab):" "49452" COTURN_MAX_PORT
+    fi
+
+    local TZ_VAL="${SITE_TZ:-$(cat /etc/timezone 2>/dev/null || echo UTC)}"
+
+    cat > docker-compose.yml << 'EOF'
+name: coturn
+
+services:
+  coturn:
+    image: coturn/coturn:latest
+    container_name: coturn
+    network_mode: host
+    user: root
+    env_file: .env
+    volumes:
+      - ./db:/var/lib/coturn
+    command:
+      - -n
+      - --listening-port=${COTURN_PORT:-3478}
+      - --listening-ip=0.0.0.0
+      - --fingerprint
+      - --lt-cred-mech
+      - --userdb=/var/lib/coturn/turndb
+      - --realm=${COTURN_REALM:-localhost}
+      - --min-port=${COTURN_MIN_PORT:-49152}
+      - --max-port=${COTURN_MAX_PORT:-49452}
+      - --no-tls
+      - --no-dtls
+      - --no-cli
+      - --no-multicast-peers
+      - --log-file=stdout
+    restart: unless-stopped
+EOF
+
+    cat > "$ENV_FILE" << ENVEOF
+TZ=$TZ_VAL
+
+# ── Identity — read by lib/common.sh's ensure_coturn_user() ────────────────
+# Changing these after consumers already registered breaks TURN for them
+# until each one is reconfigured — see the warning above before editing.
+COTURN_REALM=$COTURN_REALM
+COTURN_HOST=$COTURN_HOST
+COTURN_PORT=$COTURN_PORT
+COTURN_MIN_PORT=$COTURN_MIN_PORT
+COTURN_MAX_PORT=$COTURN_MAX_PORT
+ENVEOF
+    chmod 600 "$ENV_FILE"
+    chown "$ACTUAL_USER:$ACTUAL_USER" docker-compose.yml "$ENV_FILE"
+
+    log_success "coturn configured at $DIR"
+
+    # ── Firewall ──────────────────────────────────────────────────────────────
+    if command -v ufw &>/dev/null; then
+        ufw allow "${COTURN_PORT}/udp" comment 'coturn TURN/STUN' >/dev/null 2>&1
+        ufw allow "${COTURN_PORT}/tcp" comment 'coturn TURN/STUN' >/dev/null 2>&1
+        ufw allow "${COTURN_MIN_PORT}:${COTURN_MAX_PORT}/udp" comment 'coturn relay' >/dev/null 2>&1
+        log_success "UFW: opened ${COTURN_PORT}/udp+tcp and ${COTURN_MIN_PORT}-${COTURN_MAX_PORT}/udp"
+        ensure_ufw_enabled
+    fi
+
+    # ── Admin helper: list/add/remove consumers without touching compose ───────
+    cat > coturn_user.sh << 'USEREOF'
+#!/bin/bash
+# ~/docker/coturn/coturn_user.sh — manage TURN users in the shared coturn's
+# SQLite user database. Most services register themselves automatically via
+# ensure_coturn_user() (lib/common.sh) at install time — this is for manual
+# inspection/cleanup.
+#
+#   sudo ./coturn_user.sh list
+#   sudo ./coturn_user.sh add <name> <password>
+#   sudo ./coturn_user.sh remove <name>
+set -uo pipefail
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=/dev/null
+source "$HERE/.env"
+
+case "${1:-}" in
+    list)
+        docker exec coturn turnadmin -l -b /var/lib/coturn/turndb
+        ;;
+    add)
+        [ -n "${2:-}" ] && [ -n "${3:-}" ] || { echo "Usage: $0 add <name> <password>"; exit 1; }
+        docker exec coturn turnadmin -a -u "$2" -p "$3" -r "$COTURN_REALM" -b /var/lib/coturn/turndb \
+            && echo "Added: $2" \
+            || echo "Failed to add $2 — is the coturn container running?"
+        ;;
+    remove)
+        [ -n "${2:-}" ] || { echo "Usage: $0 remove <name>"; exit 1; }
+        docker exec coturn turnadmin -d -u "$2" -r "$COTURN_REALM" -b /var/lib/coturn/turndb \
+            && { echo "Removed: $2"; rm -f "$HERE/users/$2.env"; } \
+            || echo "Failed to remove $2"
+        ;;
+    *)
+        echo "Usage: $0 {list|add <name> <password>|remove <name>}"
+        exit 1
+        ;;
+esac
+USEREOF
+    chmod +x coturn_user.sh
+    chown "$ACTUAL_USER:$ACTUAL_USER" coturn_user.sh
+
+    write_readme "$DIR" << MD
+# coturn — shared TURN/STUN relay
+
+One coturn instance shared by every service on this box that needs TURN
+(Asterisk, Mattermost Calls, anything added later) — instead of each running
+its own and fighting over host ports for the relay range.
+
+Runs in long-term-credential mode with a SQLite user database. Each
+consumer gets its own dedicated username/password, registered automatically
+by that service's installer via \`ensure_coturn_user()\` — you don't
+normally need to touch this directly.
+
+## Identity
+- Realm: \`$COTURN_REALM\`
+- Host clients connect to: \`$COTURN_HOST\`
+- Listening port: \`$COTURN_PORT\`
+- Relay port range: \`$COTURN_MIN_PORT-$COTURN_MAX_PORT\` (udp)
+
+**Changing any of the above breaks TURN for every already-registered
+consumer until that service's installer is re-run** — they cache the host/
+port/credentials in their own \`.env\` at registration time, not read live.
+
+## Manage users
+\`\`\`bash
+sudo ./coturn_user.sh list
+sudo ./coturn_user.sh add <name> <password>
+sudo ./coturn_user.sh remove <name>
+\`\`\`
+Per-consumer credentials are also cached in \`users/<name>.env\` (chmod 600)
+so a service re-running its own installer reuses the same credential
+instead of silently minting a new one and orphaning the old.
+
+## Manage the container
+\`\`\`bash
+docker compose up -d
+docker compose down
+docker compose logs -f
+docker compose pull && docker compose up -d
+\`\`\`
+
+## Adding a new service that needs TURN
+In that service's \`install_<name>()\`, after \`require_docker\`:
+\`\`\`bash
+ensure_coturn_user "my-service"
+if [ -n "\$COTURN_HOST" ]; then
+    # COTURN_HOST / COTURN_PORT / COTURN_USERNAME / COTURN_PASSWORD are set
+    # (not local — read them after the call returns, same convention as
+    # configure_caddy_for_service's CADDY_SERVICE_* out-params)
+else
+    # coturn unavailable — degrade gracefully (no TURN, or prompt to run
+    # `sudo ./setup.sh coturn` first)
+fi
+\`\`\`
+MD
+
+    local START=""
+    prompt_yn "Start coturn now? (y/n):" "y" START
+    if [ "$START" = "y" ] || [ "$START" = "Y" ]; then
+        docker compose up -d \
+            && log_success "coturn started" \
+            || log_warning "Start failed — check: docker compose logs"
+    fi
+
+    echo ""
+    echo "  Realm: $COTURN_REALM   Host: $COTURN_HOST   Port: $COTURN_PORT"
+    echo "  Relay range: $COTURN_MIN_PORT-$COTURN_MAX_PORT/udp"
+    echo ""
+}
+
+# Run immediately when executed directly (deferred until after function definition)
+[[ "${_RUN_STANDALONE:-0}" == 1 ]] && install_coturn
diff --git a/services/immich.sh b/services/immich.sh
index 46cbd06..2f2e1b6 100644
--- a/services/immich.sh
+++ b/services/immich.sh
@@ -286,8 +286,13 @@ install_immich() {
     cd "$IMMICH_DIR" || return 1
 
     # ── Generate DB password ────────────────────────────────────────────────
+    # Reused across reruns if already set — the Postgres volume keeps the
+    # password from its first init, so a fresh random one on every rerun
+    # would lock Immich out of its own database.
     local DB_PASS TZ_VAL
-    DB_PASS=$(openssl rand -base64 32 | tr -dc 'a-zA-Z0-9' | head -c 32)
+    DB_PASS=""
+    [ -f ".env" ] && DB_PASS="$(grep '^DB_PASSWORD=' .env | cut -d= -f2-)"
+    [ -n "$DB_PASS" ] || DB_PASS="$(openssl rand -base64 32 | tr -dc 'a-zA-Z0-9' | head -c 32)"
     TZ_VAL="${SITE_TZ:-$(cat /etc/timezone 2>/dev/null || echo UTC)}"
 
     # ── Write docker-compose.yml ────────────────────────────────────────────
diff --git a/services/joplin.sh b/services/joplin.sh
index bae8650..b161743 100644
--- a/services/joplin.sh
+++ b/services/joplin.sh
@@ -197,8 +197,12 @@ install_joplin() {
     ensure_docker_dir_ownership "$JOPLIN_DIR"
     cd "$JOPLIN_DIR" || return 1
 
-    local DB_PASS
-    DB_PASS="$(generate_password 32)"
+    # Reused across reruns if already set — the Postgres volume keeps the
+    # password from its first init, so a fresh random one on every rerun
+    # would lock Joplin out of its own database.
+    local DB_PASS=""
+    [ -f ".env" ] && DB_PASS="$(grep '^POSTGRES_PASSWORD=' .env | cut -d= -f2-)"
+    [ -n "$DB_PASS" ] || DB_PASS="$(generate_password 32)"
     local BASE_URL="https://joplin.${SITE_DOMAIN}"
 
     # Mirrors configure_caddy_for_service's own mode resolution (lib/common.sh):
diff --git a/services/koha.sh b/services/koha.sh
index 6b0b692..c68258e 100644
--- a/services/koha.sh
+++ b/services/koha.sh
@@ -336,10 +336,27 @@ install_koha() {
     fi
 
     # ── Passwords ─────────────────────────────────────────────────────────────
+    # Reused across reruns if already set — the MariaDB volume keeps
+    # DB_PASS/DB_ROOT_PASS from first init, and an already-created Koha admin
+    # account keeps its own KOHA_ADMIN_PASS; regenerating any of these on a
+    # rerun would lock the reinstall out of both the database and
+    # post-setup.sh's REST API login.
     local DB_PASS DB_ROOT_PASS RABBIT_PASS
-    DB_PASS="$(generate_password 24)"
-    DB_ROOT_PASS="$(generate_password 24)"
-    RABBIT_PASS="$(generate_password 24)"
+    local _existing_koha_conf="$KOHA_DIR/config-main.env"
+    if [ -f "$_existing_koha_conf" ]; then
+        DB_PASS="$(grep '^DB_PASS=' "$_existing_koha_conf" | cut -d= -f2-)"
+        DB_ROOT_PASS="$(grep '^DB_ROOT_PASS=' "$_existing_koha_conf" | cut -d= -f2-)"
+        RABBIT_PASS="$(grep '^RABBIT_PASS=' "$_existing_koha_conf" | cut -d= -f2-)"
+        local _existing_admin_pass
+        _existing_admin_pass="$(grep '^KOHA_ADMIN_PASS=' "$_existing_koha_conf" | cut -d= -f2-)"
+        if [ -n "$_existing_admin_pass" ]; then
+            KOHA_ADMIN_PASS="$_existing_admin_pass"
+            log_info "Existing install detected — reusing its DB/admin passwords instead of what was just entered above, so this rebuild doesn't lock out the already-initialized database and admin account."
+        fi
+    fi
+    [ -n "${DB_PASS:-}" ] || DB_PASS="$(generate_password 24)"
+    [ -n "${DB_ROOT_PASS:-}" ] || DB_ROOT_PASS="$(generate_password 24)"
+    [ -n "${RABBIT_PASS:-}" ] || RABBIT_PASS="$(generate_password 24)"
 
     # ── Create directories ────────────────────────────────────────────────────
     mkdir -p "$KOHA_DIR/data"
diff --git a/services/mail-archiver.sh b/services/mail-archiver.sh
index 995c2f9..1101ec5 100644
--- a/services/mail-archiver.sh
+++ b/services/mail-archiver.sh
@@ -207,9 +207,18 @@ install_mail-archiver() {
     ensure_docker_dir_ownership "$MA_DIR"
     cd "$MA_DIR" || return 1
 
+    # Reused across reruns if already set — the Postgres volume keeps
+    # DB_PASS from its first init, and an already-created admin account
+    # keeps ADMIN_PASS; regenerating either on a rerun would lock the
+    # reinstall out of the database and the app's own admin login.
     local DB_PASS ADMIN_PASS TZ_VAL
-    DB_PASS=$(generate_password 32)
-    ADMIN_PASS=$(generate_password 24)
+    DB_PASS="" ADMIN_PASS=""
+    if [ -f ".env" ]; then
+        DB_PASS="$(grep '^POSTGRES_PASSWORD=' .env | cut -d= -f2-)"
+        ADMIN_PASS="$(grep '^Authentication__Password=' .env | cut -d= -f2-)"
+    fi
+    [ -n "$DB_PASS" ] || DB_PASS="$(generate_password 32)"
+    [ -n "$ADMIN_PASS" ] || ADMIN_PASS="$(generate_password 24)"
     TZ_VAL="${SITE_TZ:-$(cat /etc/timezone 2>/dev/null || echo UTC)}"
 
     # Mirrors configure_caddy_for_service's own mode resolution (lib/common.sh):
diff --git a/services/mattermost.sh b/services/mattermost.sh
index 3a2f098..390d496 100644
--- a/services/mattermost.sh
+++ b/services/mattermost.sh
@@ -208,40 +208,129 @@ CBLOCK
 fi
 # ─────────────────────────────────────────────────────────────────────────────
 
-register_service mattermost utilities "Team messaging with voice/video calls (Mattermost + coturn)" 8065
+register_service mattermost utilities "Team messaging with voice/video calls (Mattermost; TURN via the shared coturn service); supports multiple isolated instances" 8065
 
 install_mattermost() {
     require_docker || return 1
-    log_info "Installing Mattermost + coturn..."
 
+    # ── Instance selection ──────────────────────────────────────────────────
+    # First instance keeps the plain "mattermost" name/paths/ports exactly as
+    # before (zero behavior change for anyone with a single instance). Only
+    # asking to add a second one introduces the suffixed naming.
     local DIR="$DOCKER_DIR/mattermost"
+    local INSTANCE_SUFFIX="" PROJECT="mattermost"
+    local MM_CONTAINER="mattermost" DB_CONTAINER="mattermost-db"
+    local WEB_PORT="8065" CALLS_UDP_PORT="8443"
+    local COTURN_CONSUMER="mattermost"
+
+    if [ -d "$DIR" ]; then
+        echo ""
+        echo "  Mattermost is already installed at $DIR."
+        echo "    1) Manage that install (update / full reinstall / cancel)"
+        echo "    2) Add a NEW, separate Mattermost instance alongside it (its own"
+        echo "       server, database, and TURN credential — full isolation, not Teams)"
+        echo ""
+        local _TOP_CHOICE=""
+        prompt_text "  Choice [1/2]:" "1" _TOP_CHOICE
+        if [ "$_TOP_CHOICE" = "2" ]; then
+            local _suffix=""
+            while true; do
+                prompt_text "  Short name for the new instance (letters/numbers/hyphens, e.g. 'team-b'):" "" _suffix
+                _suffix="$(echo "$_suffix" | tr -cs 'a-zA-Z0-9-' '-' | sed 's/^-*//;s/-*$//')"
+                if [ -z "$_suffix" ]; then
+                    log_warning "Name can't be empty."; continue
+                fi
+                if [ -d "$DOCKER_DIR/mattermost-$_suffix" ]; then
+                    log_warning "mattermost-$_suffix already exists — pick another name."; continue
+                fi
+                break
+            done
+            INSTANCE_SUFFIX="$_suffix"
+            DIR="$DOCKER_DIR/mattermost-$_suffix"
+            PROJECT="mattermost-$_suffix"
+            MM_CONTAINER="mattermost-$_suffix"
+            DB_CONTAINER="mattermost-$_suffix-db"
+            COTURN_CONSUMER="mattermost-$_suffix"
+
+            # Free-port scan — same pattern services/asterisk.sh uses for its
+            # web admin port. WEB_PORT is also set as Mattermost's own
+            # internal ListenAddress below (not just the host publish side),
+            # so configure_caddy_for_service's single upstream "name:port"
+            # string works unmodified in both local and remote-Caddy mode —
+            # it assumes host-published-port == container-internal-port,
+            # true for every other service in this repo and made true here
+            # too rather than special-casing the shared helper for one caller.
+            while ss -tlnH "sport = :${WEB_PORT}" 2>/dev/null | grep -q .; do
+                WEB_PORT=$((WEB_PORT + 1))
+            done
+            while ss -ulnH "sport = :${CALLS_UDP_PORT}" 2>/dev/null | grep -q .; do
+                CALLS_UDP_PORT=$((CALLS_UDP_PORT + 1))
+            done
+            log_info "New instance: $DIR (web port $WEB_PORT, Calls UDP port $CALLS_UDP_PORT)"
+        fi
+    fi
+
+    log_info "Installing Mattermost${INSTANCE_SUFFIX:+ ($INSTANCE_SUFFIX)}..."
 
     if [ "$DRY_RUN" = true ]; then
         echo "[DRY-RUN] Would create $DIR with docker-compose.yml"
         echo "[DRY-RUN] Would write .env with DB and Mattermost secrets"
         echo "[DRY-RUN] Would create data/ logs/ config/ plugins/ db/ subdirectories"
-        echo "[DRY-RUN] Would open UFW ports 8443/udp, 3479, 49153:49352/udp"
+        echo "[DRY-RUN] Would register a TURN user with the shared coturn service for '$COTURN_CONSUMER'"
+        echo "[DRY-RUN]   (falling back to a dedicated coturn if the shared service is unavailable)"
+        echo "[DRY-RUN] Would open UFW ports ${WEB_PORT}/tcp, ${CALLS_UDP_PORT}/udp"
         return 0
     fi
 
+    # ── Existing install (this exact instance)? Offer update-in-place ───────
+    local MODE="fresh"
+    local _HAD_EMBEDDED_COTURN=false
+    if [[ -f "$DIR/docker-compose.yml" && -f "$DIR/.env" ]]; then
+        prompt_reinstall_mode MODE
+        grep -q '^  coturn:' "$DIR/docker-compose.yml" 2>/dev/null && _HAD_EMBEDDED_COTURN=true
+        case "$MODE" in
+            cancel)
+                log_info "Leaving the existing install as-is."
+                return 0
+                ;;
+            fresh)
+                if [ "$_HAD_EMBEDDED_COTURN" = true ]; then
+                    echo ""
+                    log_warning "This install has its own dedicated coturn. Continuing may switch it to"
+                    log_warning "the shared coturn service — the Calls plugin's TURN config in System"
+                    log_warning "Console will need updating to the new credentials afterward (see below)."
+                fi
+                ;;
+        esac
+    fi
+
     mkdir -p "$DIR"
     ensure_docker_dir_ownership "$DIR"
     cd "$DIR" || return 1
 
-    local DB_PASS
-    local MM_SECRET
-    DB_PASS=$(generate_password 32)
-    MM_SECRET=$(generate_password 48)
+    # Reuse existing secrets on update — Postgres's volume keeps the password
+    # from its first init, so overwriting .env with a fresh one locks
+    # Mattermost out of its own database. Confirmed this was previously
+    # unconditional (regenerated every single rerun, silently breaking the DB
+    # connection) — fixed here as part of adding proper update detection.
+    local DB_PASS="" MM_SECRET=""
+    if [ "$MODE" = "update" ]; then
+        DB_PASS="$(grep '^POSTGRES_PASSWORD=' .env 2>/dev/null | cut -d= -f2-)"
+        [ "$_HAD_EMBEDDED_COTURN" = true ] && MM_SECRET="$(grep '^COTURN_SECRET=' .env 2>/dev/null | cut -d= -f2-)"
+    fi
+    [ -n "$DB_PASS" ] || DB_PASS=$(generate_password 32)
 
     local TZ_VAL="${SITE_TZ:-$(cat /etc/timezone 2>/dev/null || echo UTC)}"
     local UID_VAL GID_VAL
     UID_VAL=$(id -u "$ACTUAL_USER")
     GID_VAL=$(id -g "$ACTUAL_USER")
 
-    # Compute SITE_URL
-    local SITE_URL="http://localhost:8065"
+    # Compute SITE_URL — extra instances default to a distinct subdomain so
+    # they don't collide with the first instance's.
+    local _default_subdomain="mattermost${INSTANCE_SUFFIX:+-$INSTANCE_SUFFIX}"
+    local SITE_URL="http://localhost:${WEB_PORT}"
     if [ -n "$SITE_DOMAIN" ] && [ "$SITE_DOMAIN" != "example.com" ]; then
-        SITE_URL="https://mattermost.${SITE_DOMAIN}"
+        SITE_URL="https://${_default_subdomain}.${SITE_DOMAIN}"
     fi
     local CONFIGURED_SITEURL=""
     prompt_text "Mattermost site URL [$SITE_URL]:" "$SITE_URL" CONFIGURED_SITEURL
@@ -270,45 +359,34 @@ networks:
 "
     fi
 
-    cat > docker-compose.yml << EOF
-name: mattermost
+    # ── TURN: shared coturn preferred, dedicated coturn as fallback ─────────
+    # See services/coturn.sh's header for why one shared TURN server beats
+    # every service (Asterisk, each Mattermost instance, ...) running its
+    # own and fighting over host relay ports.
+    local USE_EMBEDDED_COTURN=true
+    local TURN_HOST_VAL="" TURN_PORT_VAL="" TURN_USERNAME_VAL="" TURN_PASSWORD_VAL=""
 
-services:
-  db:
-    image: postgres:15-alpine
-    container_name: mattermost-db
-    hostname: mattermost-db
-    restart: unless-stopped
-    env_file: .env
-    volumes:
-      - ./db:/var/lib/postgresql/data
-${_CADDY_NET_BLOCK}    healthcheck:
-      test: ["CMD-SHELL", "pg_isready -U \${POSTGRES_USER} -d \${POSTGRES_DB}"]
-      interval: 10s
-      timeout: 5s
-      retries: 5
+    if [ "$MODE" = "update" ] && [ "$_HAD_EMBEDDED_COTURN" = true ]; then
+        USE_EMBEDDED_COTURN=true   # preserve exactly — never switch on update
+    else
+        ensure_coturn_user "$COTURN_CONSUMER"
+        if [ -n "${COTURN_HOST:-}" ]; then
+            USE_EMBEDDED_COTURN=false
+            TURN_HOST_VAL="$COTURN_HOST"; TURN_PORT_VAL="$COTURN_PORT"
+            TURN_USERNAME_VAL="$COTURN_USERNAME"; TURN_PASSWORD_VAL="$COTURN_PASSWORD"
+            log_success "Using the shared coturn service — TURN username '$COTURN_USERNAME'."
+        else
+            log_info "Shared coturn unavailable — this instance will run its own dedicated coturn."
+        fi
+    fi
+    [ -n "$MM_SECRET" ] || MM_SECRET=$(generate_password 48)
 
-  mattermost:
-    image: mattermost/mattermost-team-edition:latest
-    container_name: mattermost
-    hostname: mattermost
-    restart: unless-stopped
-    env_file: .env
-    depends_on:
-      db:
-        condition: service_healthy
-    volumes:
-      - ./data:/mattermost/data
-      - ./logs:/mattermost/logs
-      - ./config:/mattermost/config
-      - ./plugins:/mattermost/plugins
-    ports:
-      - "8065:8065"
-      - "8443:8443/udp"
-${_CADDY_NET_BLOCK}
+    local _COTURN_SERVICE=""
+    if [ "$USE_EMBEDDED_COTURN" = true ]; then
+        _COTURN_SERVICE="
   coturn:
     image: coturn/coturn:latest
-    container_name: mattermost-coturn
+    container_name: ${MM_CONTAINER}-coturn
     network_mode: host
     user: root
     command:
@@ -327,7 +405,45 @@ ${_CADDY_NET_BLOCK}
       - --no-multicast-peers
       - --log-file=stdout
     restart: unless-stopped
-${_CADDY_NET_SECTION}
+"
+    fi
+
+    cat > docker-compose.yml << EOF
+name: ${PROJECT}
+
+services:
+  db:
+    image: postgres:15-alpine
+    container_name: ${DB_CONTAINER}
+    hostname: ${DB_CONTAINER}
+    restart: unless-stopped
+    env_file: .env
+    volumes:
+      - ./db:/var/lib/postgresql/data
+${_CADDY_NET_BLOCK}    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U \${POSTGRES_USER} -d \${POSTGRES_DB}"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+  mattermost:
+    image: mattermost/mattermost-team-edition:latest
+    container_name: ${MM_CONTAINER}
+    hostname: ${MM_CONTAINER}
+    restart: unless-stopped
+    env_file: .env
+    depends_on:
+      db:
+        condition: service_healthy
+    volumes:
+      - ./data:/mattermost/data
+      - ./logs:/mattermost/logs
+      - ./config:/mattermost/config
+      - ./plugins:/mattermost/plugins
+    ports:
+      - "${WEB_PORT}:${WEB_PORT}"
+      - "${CALLS_UDP_PORT}:8443/udp"
+${_CADDY_NET_BLOCK}${_COTURN_SERVICE}${_CADDY_NET_SECTION}
 EOF
 
     cat > .env << EOF
@@ -341,15 +457,24 @@ POSTGRES_PASSWORD=$DB_PASS
 
 # Mattermost
 MM_SQLSETTINGS_DRIVERNAME=postgres
-MM_SQLSETTINGS_DATASOURCE=postgres://mattermost:${DB_PASS}@mattermost-db:5432/mattermost?sslmode=disable&connect_timeout=10
+MM_SQLSETTINGS_DATASOURCE=postgres://mattermost:${DB_PASS}@${DB_CONTAINER}:5432/mattermost?sslmode=disable&connect_timeout=10
 MM_SERVICESETTINGS_SITEURL=$SITE_URL
+MM_SERVICESETTINGS_LISTENADDRESS=:${WEB_PORT}
 MM_SERVICESETTINGS_ENABLELOCALMODE=true
 MM_FILESETTINGS_DRIVERNAME=local
 MM_PLUGINSETTINGS_ENABLE=true
 
-# coturn HMAC secret for Mattermost Calls plugin
+# ── TURN/STUN (Calls plugin) ─────────────────────────────────
+$( [ "$USE_EMBEDDED_COTURN" = true ] \
+    && echo "# This instance runs its own dedicated coturn (the coturn: service in docker-compose.yml)." \
+    || echo "# Using the shared coturn service — see ~/docker/coturn/README.md." )
+# coturn HMAC secret — only used if this instance runs its own dedicated coturn.
 COTURN_SECRET=$MM_SECRET
 MM_REALM=${SITE_DOMAIN:-localhost}
+TURN_HOST=$TURN_HOST_VAL
+TURN_PORT=$TURN_PORT_VAL
+TURN_USERNAME=$TURN_USERNAME_VAL
+TURN_PASSWORD=$TURN_PASSWORD_VAL
 
 # PUID/PGID for file ownership
 PUID=$UID_VAL
@@ -360,34 +485,99 @@ EOF
     mkdir -p data logs config plugins db
     chown -R "$ACTUAL_USER:$ACTUAL_USER" "$DIR"
 
-    # Open required firewall ports
+    # ── Firewall ─────────────────────────────────────────────────────────────
     if command -v ufw &>/dev/null; then
-        ufw allow 8443/udp comment "Mattermost Calls RTC"
-        ufw allow 3479/udp; ufw allow 3479/tcp
-        ufw allow 49153:49352/udp comment "Mattermost coturn relay"
+        ufw allow "${WEB_PORT}/tcp" comment "Mattermost${INSTANCE_SUFFIX:+ ($INSTANCE_SUFFIX)}"
+        ufw allow "${CALLS_UDP_PORT}/udp" comment "Mattermost Calls RTC${INSTANCE_SUFFIX:+ ($INSTANCE_SUFFIX)}"
+        if [ "$USE_EMBEDDED_COTURN" = true ]; then
+            ufw allow 3479/udp; ufw allow 3479/tcp
+            ufw allow 49153:49352/udp comment "Mattermost coturn relay"
+        fi
+        # Shared coturn opens its own ports once, at its own install time.
     fi
 
     echo ""
     log_success "Mattermost configured at $DIR"
 
-    configure_caddy_for_service "Mattermost" "mattermost:8065" "mattermost"
+    configure_caddy_for_service "Mattermost${INSTANCE_SUFFIX:+ ($INSTANCE_SUFFIX)}" "${MM_CONTAINER}:${WEB_PORT}" "$_default_subdomain"
+
+    # Exact ICEServersConfigs JSON to paste into System Console — verified
+    # against the Calls plugin's actual config schema (plugin.json): this
+    # field takes a fixed username/credential pair, which is what a
+    # --lt-cred-mech coturn (shared or dedicated) expects, as opposed to the
+    # "TURN Static Auth Secret" field (HMAC/REST-API mode, which coturn
+    # cannot run at the same time as --lt-cred-mech on one instance).
+    local _ICE_JSON _turn_config_md
+    if [ "$USE_EMBEDDED_COTURN" = true ]; then
+        _ICE_JSON="[{\"urls\":[\"turn:${SITE_DOMAIN:-YOUR_IP}:3479?transport=udp\"],\"username\":\"static\",\"credential\":\"see COTURN_SECRET below — this dedicated coturn uses use-auth-secret/HMAC, not a fixed credential\"}]"
+        _turn_config_md="This instance runs its own dedicated coturn (HMAC/REST-API auth):
+- TURN Server URI: \`turn:${SITE_DOMAIN:-YOUR_IP}:3479?transport=udp\`
+- System Console → Plugins → Calls → **TURN Static Auth Secret**: value of \`COTURN_SECRET\` in \`.env\`"
+    else
+        _ICE_JSON="[{\"urls\":[\"turn:${TURN_HOST_VAL}:${TURN_PORT_VAL}?transport=udp\"],\"username\":\"${TURN_USERNAME_VAL}\",\"credential\":\"${TURN_PASSWORD_VAL}\"}]"
+        _turn_config_md="This instance uses the shared coturn service (fixed username/credential, not HMAC):
+- System Console → Plugins → Calls → **ICE Servers Configurations** — paste:
+\`\`\`json
+$_ICE_JSON
+\`\`\`
+- Leave **TURN Static Auth Secret** empty — that field is for the OTHER auth
+  mode coturn supports and doesn't apply here."
+    fi
+    [ "${CALLS_UDP_PORT}" != "8443" ] && _turn_config_md="$_turn_config_md
+- System Console → Plugins → Calls → **ICE Host Port Override**: \`${CALLS_UDP_PORT}\` (this instance publishes Calls RTC on a non-default port)"
 
     write_readme "$DIR" << MD
-# Mattermost
+# Mattermost${INSTANCE_SUFFIX:+ — $INSTANCE_SUFFIX}
 
-Team messaging with voice/video calls. PostgreSQL backend + coturn TURN relay.
+Team messaging with voice/video calls. PostgreSQL backend.
+$( [ -n "$INSTANCE_SUFFIX" ] && echo "
+
+This is a separate, fully isolated instance (own server, own database, own
+TURN credential) — not a Team within another instance. See that instance's
+own README for its own access details." )
 
 ## Access
-- URL: $SITE_URL (or http://localhost:8065)
-- First run: create admin account at the URL above
+- URL: $SITE_URL (or http://localhost:${WEB_PORT})
+- First run: create admin account at the URL above — this account becomes
+  System Admin automatically.
+
+## Teams
+Team Edition (the free edition this installer uses) includes multiple Teams
+natively — separate spaces (their own channels, their own members) on the
+same server, same database, same login. No Enterprise license needed; this
+is the resource-efficient alternative to running a second Mattermost
+instance for a second group.
+
+Create one:
+- Click the **+** at the bottom of the team sidebar (the narrow column on
+  the far left) → **Create a new team**, or
+- System Console → User Management → Teams → **Create Team**
+
+Add people to a team:
+- Team name (top-left) → **Invite People** → share the invite link, or send
+  email invites (requires SMTP — System Console → Environment → SMTP), or
+- System Console → User Management → Teams → the team → **Add Members**
+  (adds existing server accounts directly, no invite flow)
+
+Users can belong to more than one team and switch between them via the team
+sidebar icons. By default any user can create a team — restrict that at
+System Console → User Management → Permissions if you only want admins
+creating them.
+
+By default, Direct Messages ignore team boundaries — anyone on the server
+can DM anyone else regardless of shared team membership. To limit the DM
+picker to teammates only: **System Console → Site Configuration → Users and
+Teams → "Enable users to open Direct Message channels with" → Any member of
+the team** (free in Team Edition, no license needed). This is a UI filter,
+not a hard boundary — it doesn't hide DM channels that already exist, and a
+user in multiple teams can still DM anyone across all of them, not just the
+team currently open. If you need real isolation between groups rather than
+a tidier picker, that means separate Mattermost instances, not this setting.
 
 ## Voice/Video Calls (Calls plugin)
-Port 8443/udp must be open on your router/firewall.
-coturn relay runs on port 3479 (HMAC secret in .env).
+Port ${CALLS_UDP_PORT}/udp must be open on your router/firewall.
 
-Configure in Mattermost: System Console → Plugins → Calls:
-- TURN Server URI: turn:YOUR_DOMAIN_OR_IP:3479?transport=udp
-- TURN Credentials: use static-auth-secret (see .env COTURN_SECRET)
+${_turn_config_md}
 
 ## Manage
 \`\`\`bash
@@ -413,9 +603,9 @@ MD
     echo ""
     echo "  Access at:  $SITE_URL"
     echo "  First run:  open the URL above and create your admin account."
-    echo "  Calls plugin: System Console → Plugins → Calls to configure coturn."
-    echo "    TURN URI:    turn:${SITE_DOMAIN:-YOUR_IP}:3479?transport=udp"
-    echo "    Auth secret: see COTURN_SECRET in $DIR/.env"
+    echo "  Teams:      team sidebar '+' → Create a new team (see README.md — no"
+    echo "              Enterprise license needed, Team Edition includes this)."
+    echo "  Calls plugin TURN config: see README.md (System Console → Plugins → Calls)."
     echo ""
 }
 
diff --git a/services/nextcloud.sh b/services/nextcloud.sh
index fefbdcd..addd268 100644
--- a/services/nextcloud.sh
+++ b/services/nextcloud.sh
@@ -190,10 +190,18 @@ install_nextcloud() {
     ensure_docker_dir_ownership "$DIR"
     cd "$DIR" || return 1
 
-    local DB_PASS
-    DB_PASS=$(generate_password 32)
-    local NC_ADMIN_PASS
-    NC_ADMIN_PASS=$(generate_password 16)
+    # Reused across reruns if already set — the MariaDB volume keeps DB_PASS
+    # from its first init (regenerating it would lock Nextcloud out of its
+    # own database), and NEXTCLOUD_ADMIN_USER/PASSWORD are only consulted by
+    # the container on its very first boot to create the admin account —
+    # printing a fresh NC_ADMIN_PASS on every rerun would silently show a
+    # password that was never actually applied to the existing account.
+    local DB_PASS=""
+    [ -f ".env" ] && DB_PASS="$(grep '^MYSQL_PASSWORD=' .env | cut -d= -f2-)"
+    [ -n "$DB_PASS" ] || DB_PASS="$(generate_password 32)"
+    local NC_ADMIN_PASS=""
+    [ -f ".env" ] && NC_ADMIN_PASS="$(grep '^NEXTCLOUD_ADMIN_PASSWORD=' .env | cut -d= -f2-)"
+    [ -n "$NC_ADMIN_PASS" ] || NC_ADMIN_PASS="$(generate_password 16)"
     local TZ_VAL="${SITE_TZ:-UTC}"
 
     # ── Dockerfile ──────────────────────────────────────────────────────────