Update docker.io/library/mariadb Docker tag to v12

Closes #74

inventories/chaosknoten/host_vars/pad.sops.yaml

@@ -1,6 +1,7 @@
 secret__hedgedoc_db_password: ENC[AES256_GCM,data:5Pw0orOTzb1xCefwx/n9h9m8gmEY6irE,iv:nZvnPSb6sXjS6k4wNUoo2PCJyOcwjm36gs9l0mxwAeo=,tag:0seJlVi9qTfBiol7mP6DQA==,type:str]
 secret__hedgedoc_kc_secret: ENC[AES256_GCM,data:7RyM9jfKnaaP7kJ1JwucPa/IAwaRc7Hhe9VYIKGEmlc=,iv:RvtaWLsf/X/y8s+DLANcyVgagJqGB7EkvQ2nYm2Xo24=,tag:amdgqknDGeZxUBmXsd1ksw==,type:str]
 secret__pad_smtp_password: ENC[AES256_GCM,data:msnYZYl8vP+OeISI5OOglQsCQ8vxMZ0gig==,iv:oqov/myWJNzUoAn4BSX6hN1fWyab5vud8NmT+z4ECqs=,tag:0T3Xm2zw5k5WmC9Ks03XhA==,type:str]
+secret__hedgedoc_session_secret: ENC[AES256_GCM,data:pHm05ETouEOfbjnallwvhifEz0qB/sMdhYNYqDKKcQyOpk970WRfjNYXh2Be+MCcM9aZjJkHv/2Jc23jngETfg==,iv:z+IWBen08PJGdz9kc8RbPu07oZua2e+IlOfhhleAqUo=,tag:JJ8MM8WP8z53TrafVJ0/PQ==,type:str]
 ansible_pull__age_private_key: ENC[AES256_GCM,data:r9j1ikemQXl+Fq3D141P/MVltGLR27UyHxCCWnZphOLyGhyhQgqcuFqwPy1kZhnbg/mj5DclJ8rzqyH65T0XQu9h8d/vh7Apm4c=,iv:xOmxBTVIOTRt3rzWM8wHKVD7UHeuPj2+NSHJnCvU4xo=,tag:CA9dR+/rB/wfcPuU/+zwsA==,type:str]
 sops:
   age:
@@ -13,8 +14,8 @@ sops:
         SzRBbUNaWUZMb2hXckQ5ekFPQ0hSQ2MKYcb+ylmw46a5xmDZSW5HfxUvwtsH2Aqw
         hgMNTkiAKyo9JWjhbAwdkZd75BTsukIB5846Fbblpjo8kGdP10H6vg==
         -----END AGE ENCRYPTED FILE-----
-  lastmodified: "2025-10-20T18:59:09Z"
-  mac: ENC[AES256_GCM,data:3BwneKrw8YKmfwIoDyNRo+SG6i6VMW5tECQrhMXiq/mB/14xHHrUcrWRanFknm6JB518Ohv5HEjeHsrYdUehwpzsl1vtCji95osa8JdZY5moAt+4f06viRFTYa6GrfnNKToUR9obZFiPAHlMXcTTx6y0m/nPrtFZhuNtFssOdxg=,iv:4fElvIvapfqSqxRLE/NSiWyun5hAA8JLsai/Eoa5K68=,tag:mPKOquAMj43I0WhK6budLQ==,type:str]
+  lastmodified: "2026-03-09T20:05:54Z"
+  mac: ENC[AES256_GCM,data:iTfsv2WoOoP4RHWRhau/8olT5BQn2jWE+iizKuVSGIqcG/MZKastj536ZjhM5GYZXyROXEObAenB7G7Zjy9rK5cv4QUIw0FiYN0irObOcXm6/mlVb0OoYHv4ObPhRvGidDNONhILIJwW8+TOHPMfwnhswff8+32gkVvdZtk1u4A=,iv:elNrdohgQVtqxSX6IC8lNUF0mWPV+maYX2MrletkqV0=,tag:RHAlazcp6mp+BLomFV7Z3w==,type:str]
   pgp:
     - created_at: "2026-03-05T19:18:04Z"
       enc: |-
@@ -216,4 +217,4 @@ sops:
         -----END PGP MESSAGE-----
       fp: 41FFAF3D519CF5C039FBD8414BCC213729AF0E49
   unencrypted_suffix: _unencrypted
-  version: 3.11.0
+  version: 3.12.1

resources/chaosknoten/ccchoir/docker_compose/compose.yaml.j2

@@ -3,7 +3,7 @@
 
 services:
   database:
-    image: docker.io/library/mariadb:11
+    image: docker.io/library/mariadb:12
     environment:
       - "MARIADB_DATABASE=wordpress"
       - "MARIADB_ROOT_PASSWORD={{ secret__mariadb_root_password }}"

resources/chaosknoten/grafana/docker_compose/prometheus_alerts-fux.rules.yaml

@@ -10,6 +10,15 @@ groups:
         annotations:
           summary: Job {{ $labels.job }} flaky on (instance {{ $labels.instance }})
           description: "The job {{ $labels.job }} on target: {{ $labels.instance }} has been flaky over the last 24 hours."
+      - alert: ProbeFailed
+        expr: group by(instance, job, ip) (probe_success{org="fux"} == 0)
+        for: 1m
+        labels:
+          severity: critical
+          org: fux
+        annotations:
+          summary: "Probe failed for {{ $labels.instance }} (job: {{ $labels.job }})"
+          description: "The Probe: {{ $labels.job }} can not complete its job for {{ $labels.instance }}, this most likely means that the instance is unreachable."
   - name: Fux-SNMP
     rules:
       - alert: SnmpTargetMissing

resources/chaosknoten/pad/docker_compose/compose.yaml.j2

@@ -37,6 +37,7 @@ services:
       - "CMD_OAUTH2_CLIENT_SECRET={{ secret__hedgedoc_kc_secret }}"
       - "CMD_OAUTH2_PROVIDERNAME=Keycloak"
       - "CMD_OAUTH2_SCOPE=openid email profile"
+      - "CMD_SESSION_SECRET={{ secret__hedgedoc_session_secret }}"
     volumes:
       - uploads:/hedgedoc/public/uploads
     ports: