tasks: container_create: Retry if sysctl-container service failed to start

This aims to workaround an issue on openSUSE where the service may fail
to start with the following error:

sysctl-container.service: Failed at step CGROUP spawning /sbin/sysctl: No such device

Related-Bug: #1712741
Link: https://bugzilla.suse.com/show_bug.cgi?id=1055426
Change-Id: If66f1f9d0f51173890004b65c332f14fc878fb18

tasks/container_create.yml

@@ -529,6 +529,13 @@
   tags:
     - lxc_container_create-sysctl
 
+# NOTE(hwoarang) openSUSE randomly fails to start the service
+# with an error like the following one
+# sysctl-container.service: Failed at step CGROUP spawning /sbin/sysctl: No such device
+# Until this is fixed, we workaround it by simply retrying a few more times
+# before giving up
+# https://bugzilla.suse.com/show_bug.cgi?id=1055426
+# https://bugs.launchpad.net/openstack-ansible/+bug/1712741
 - name: Enable container sysctl service
   service:
     name: "sysctl-container"
@@ -536,6 +543,10 @@
     enabled: yes
     daemon_reload: yes
   remote_user: root
+  register: _sysctl_service_started
+  until: _sysctl_service_started|success
+  retries: 5
+  delay: 5
   tags:
     - lxc_container_create-sysctl