Hello/Hi/Greetings,

Well after a couple of weeks running fine, my NAS rebooted and I can't access Piwigo anymore.
It's running on a Raspberry PI with OpenMediaVault and Portainer which created 1 stack with 2 containers with the standard docker compose file suitably modified with my local details.

Here's the docker compose file
version: "2.1"
services:
  piwigo:
    image: linuxserver/piwigo
    container_name: piwigo
    environment:
      - PUID=1000 
      - PGID=100
      - TZ=Europe/Paris
    volumes:
      - /srv/dev-disk-by-uuid-f9ecd315-cd47-47e7-9d27-0289dc14c865/mainshare/Photos:/config
    ports:
      - 8125:80
    restart: unless-stopped
  mariadb:
    image: linuxserver/mariadb
    container_name: piwidb
    environment:
      - PUID=1000
      - PGID=100
      - MYSQL_ROOT_PASSWORD=.I.........w
      - TZ=Europe/Paris
      - MYSQL_DATABASE=piwigo
      - MYSQL_USER=piwigo
      - MYSQL_PASSWORD=piwigo
    volumes:
      - /srv/dev-disk-by-uuid-be79d0a1-9a27-456c-a32d-46faba7223a2/piwidb:/config
    ports:
      - 3306:3306
    restart: unless-stopped

The stack created a network with the 2 container IP addresses 172.19.0.3 for piwidb container and 172.19.0.2 for piwigo container

As mentioned this worked and I uploaded a bunch of albums over the course of 10 days but after the reboot Piwigo gets a mysql connection refused, the error is the same as many others have reported

Warning: Attempt to read property "errno" on null in /app/www/public/include/dblayer/functions_mysqli.inc.php on line 839

Warning: Attempt to read property "error" on null in /app/www/public/include/dblayer/functions_mysqli.inc.php on line 839
Piwigo encountered a non recoverable error

[mysql error ]
Connection refused

#1    my_error /app/www/public/include/common.inc.php(124)
#2    include_once /app/www/public/index.php(11)

I'm not much of a DBA nor at all conversant with docker, just Ok with Unix.

If there are logs to examine, I can access each container's console to search and read, but I don't where to look.

On the piwidb container, I tried service status mysql, but got service not found.

There's ample space for the DB which has its own 2TB volume,

root@f2ce7003d12d:/# df
Filesystem      1K-blocks    Used  Available Use% Mounted on
overlay          60820700 9448356   48264268  17% /
tmpfs               65536       0      65536   0% /dev
shm                 65536       0      65536   0% /dev/shm
/dev/sdc1      1921724676  331604 1921376688   1% /config
/dev/mmcblk0p2   60820700 9448356   48264268  17% /etc/hosts
tmpfs             4004304       0    4004304   0% /proc/asound
tmpfs             4004304       0    4004304   0% /sys/firmware

So I'm stumped for the moment.

Any pointers very much welcomed, there can't be much wrong here it all worked before reboot


Environment

    Piwigo 15.6.0 Check for upgrade
    Installed on 22 August 2025, 4 days ago
    Operating system: Linux
    PHP: 8.3.19 (Show info) [2025-08-27 15:34:13]
    MySQL: 11.4.5-MariaDB-log [2025-08-27 15:34:13]
    Graphics Library: ImageMagick ImageMagick 7.1.1-41
    Cache size N/A   never calculated Refresh

Activated plugin list 4

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