Merge pull request #2854 from alexbelgium/fix/elasticsearch-runtime-root-permission

fix(elasticsearch): stay root at runtime, fix upgrade permission failure

elasticsearch/CHANGELOG.md

@@ -8,8 +8,10 @@
 - Removed the `ingest-attachment` plugin install: it is a bundled module since Elasticsearch 8.0.
 - Startup persistence logic rewritten as a proper init script (`/usr/local/bin/addon-init.sh`) instead of line-number-based entrypoint patching.
 - Added `updater.json` so upstream 8.19.x releases are tracked automatically (pinned to the 8.19 line: 9.x cannot read indices created in 7.x).
-- The upstream 8.x image ends the build as a non-root user with a read-only entrypoint; the Dockerfile now switches to root for the build steps that patch/install into it and restores the Elasticsearch user before runtime.
+- The upstream 8.x image ends the build as a non-root user with a read-only entrypoint; the Dockerfile now switches to root for the build steps that patch/install into it. The container also starts as root (unchanged from 7.17.9) so `addon-init.sh` can chown/move pre-existing `/data` content that may be owned by root from earlier installs; unlike 7.17.9's own entrypoint, the upstream 8.x entrypoint no longer drops privileges before starting Elasticsearch (which refuses to run as root), so `addon-init.sh` now does that itself via `chroot --userspec=1000:0` once its root-only work is done.
 - `env_vars` names starting with a digit are now rejected before export instead of crashing the entrypoint.
+- Fixed a startup failure (`mv: cannot move '/data/config' ... Permission denied`) on upgrade from an existing 7.17.9 install, caused by an earlier fix in this same release that switched the runtime user to non-root before this fix was in place.
+- Fixed a second regression from that same fix: without a privilege drop before starting Elasticsearch, both fresh installs and upgrades would fail Elasticsearch's own root-check ("can not run elasticsearch as root").
 
 ## 8.14.3-3 (2026-06-19)
 - Fix startup failing with `chroot: cannot change root directory` by allowing `capability sys_chroot` in the AppArmor profile (#2709)

elasticsearch/Dockerfile

@@ -141,5 +141,10 @@ HEALTHCHECK \
     --timeout=25s \
     CMD curl -A "HealthCheck: Docker/1.0" -s -f "http://127.0.0.1:${HEALTH_PORT}${HEALTH_URL}" &>/dev/null || exit 1
 
-# Restore the Elasticsearch user for runtime, matching the base image
-USER 1000:0
+# Start as root: addon-init.sh needs it to chown/move pre-existing /data
+# content that may be owned by root from earlier installs. It drops to
+# uid 1000 itself (via chroot --userspec) before Elasticsearch actually
+# starts, since Elasticsearch refuses to run as root and the upstream 8.x
+# entrypoint no longer does that drop on its own (7.x's did). This matches
+# the addon's own AppArmor profile (chown, setuid, setgid, sys_chroot,
+# mount capabilities).

elasticsearch/rootfs/usr/local/bin/addon-init.sh

@@ -1,14 +1,25 @@
 #!/bin/bash
 # shellcheck shell=bash
 # Sourced by /usr/local/bin/docker-entrypoint.sh (right after "set -e"),
-# before Elasticsearch starts. Runs as root when the Supervisor starts the
-# container; the official entrypoint then drops privileges itself.
+# before Elasticsearch starts. The container starts as root (see
+# Dockerfile) so this script can chown/move pre-existing /data content
+# that may be owned by root from earlier installs. Elasticsearch itself
+# refuses to run as root, and unlike 7.x the upstream 8.x entrypoint no
+# longer drops privileges on its own, so this script does it at the end
+# (section 6) by re-execing the entrypoint as uid 1000. On that re-exec'd
+# pass this script just returns immediately (see the guard right below).
 #
 # Responsibilities:
 #   1. Export user env_vars from /data/options.json
 #   2. Default xpack.security.enabled=false (7.x behavior) unless user overrides
 #   3. Relocate data & config to /data for persistence (idempotent)
 #   4. Guard major-version data migrations (7.x -> 8.x is automatic)
+#   5. Record the running version once Elasticsearch is confirmed healthy
+#   6. Drop root privileges before Elasticsearch actually starts
+
+if [ -n "${_ADDON_INIT_REEXEC:-}" ]; then
+    return 0
+fi
 
 echo "-----------------------------------------------------------"
 echo " Add-on: Elasticsearch server"
@@ -140,3 +151,17 @@ if [ "$data_version" != "$current_version" ]; then
         done
     ) &
 fi
+
+############################
+# 6 Drop privileges        #
+############################
+
+# Elasticsearch refuses to start as root ("can not run elasticsearch as
+# root"). 7.x's own entrypoint dropped to uid 1000 via chroot before
+# launching Elasticsearch; 8.x no longer does that, so do it here instead,
+# then let the entrypoint continue as uid 1000 (matches the sys_chroot /
+# setuid / setgid capabilities already granted in the AppArmor profile).
+if [ "$(id -u)" -eq 0 ]; then
+    export _ADDON_INIT_REEXEC=1
+    exec chroot --userspec=1000:0 / /usr/local/bin/docker-entrypoint.sh "$@"
+fi