fix: ownership of mysql data

In theory, we can assign ownership of mysql data to just any user. But in
Lilac, mysql was running with user 999. When upgrading to Maple, on Kubernetes,
the fsGroupChangePolicy was causing a change of the data *group* (to 1000) but
not of the user. This was causing a crash with the following error:

    [ERROR] InnoDB: The error means mysqld does not have the access rights to the directory.

CHANGELOG.md

@@ -4,6 +4,7 @@ Note: Breaking changes between versions are indicated by "💥".
 
 ## Unreleased
 
+- [Bugfix] Fix ownership of mysql data, in particular when upgrading a Kubernetes cluster to Maple.
 - [Bugfix] Ensure that ``tutor k8s upgrade`` is run during ``tutor k8s quickstart``, when necessary.
 - [Bugfix] By default, upgrade from Lilac and not Koa during ``tutor k8s upgrade``.
 - [Bugfix] Fix upgrading from Lilac to Maple on Kubernetes by deleting deployments and services.

tutor/templates/k8s/deployments.yml

@@ -340,9 +340,9 @@ spec:
         app.kubernetes.io/name: mysql
     spec:
       securityContext:
-        runAsUser: 1000
-        runAsGroup: 1000
-        fsGroup: 1000
+        runAsUser: 999
+        runAsGroup: 999
+        fsGroup: 999
         fsGroupChangePolicy: "OnRootMismatch"
       containers:
         - name: mysql

tutor/templates/local/docker-compose.yml

@@ -28,7 +28,7 @@ services:
     image: {{ DOCKER_IMAGE_MYSQL }}
     command: mysqld --character-set-server=utf8 --collation-server=utf8_general_ci
     restart: unless-stopped
-    user: "1000:1000"
+    user: "999:999"
     privileged: false
     volumes:
       - ../../data/mysql:/var/lib/mysql
@@ -36,7 +36,7 @@ services:
       MYSQL_ROOT_PASSWORD: "{{ MYSQL_ROOT_PASSWORD }}"
   mysql-permissions:
     image: {{ DOCKER_IMAGE_PERMISSIONS }}
-    command: ["1000", "/var/lib/mysql"]
+    command: ["999", "/var/lib/mysql"]
     restart: on-failure
     volumes:
       - ../../data/mysql:/var/lib/mysql