Solve the problem with docker runtime directory

Docker unmounts overlay2 directory when stopping. Post shutdown script
will remount it again.

.ansible-lint

 skip_list:
+  - command-instead-of-module
   - fqcn-builtins
   - yaml[line-length]

cesnet-central/playbooks/k8s.yaml

@@ -180,6 +180,33 @@
         kube_type_of_node: wn
         kube_version: 1.28.8
         kubelet_extra_args: '--volume-stats-agg-period 0'
+  tasks:
+    - name: Overlay2 mountpoint workaround to docker.service unit
+      lineinfile:
+        path: /lib/systemd/system/docker.service
+        firstmatch: true
+        insertafter: '\[Service\]'
+        line: 'ExecStopPost=mount /var/lib/docker/overlay2'
+        regexp: '^\s*ExecStopPost\s*='
+    - name: Local docker.service unit
+      copy:
+        src: /lib/systemd/system/docker.service
+        dest: /etc/systemd/system/docker.service
+        mode: 0644
+        remote_src: true
+      notify:
+        - Reload systemd daemon
+        - Restart docker
+  handlers:
+    - name: Reload systemd daemon
+      command:
+        cmd: systemctl daemon-reload
+      ignore_errors: true
+    - name: Restart docker
+      service:
+        name: docker
+        state: restarted
+
 
 - name: K8s customization
   hosts: master