Wait for systemd-tmpfiles-setup service to complete after container r…

…estart

There is a race condition between starting an lxc container and executing
the first ansible task. Ansible makes heavy use of /tmp and the first
task executed after 'lxc-start' will collide with systemd-tmpfiles-setup
which by default removes all content from /tmp, including the working
files of any ansible task which happens to be running. This causes a fatal
error for ansible which cannot be recovered with retries.

This patch adds a raw command to check the state of the tmpfiles-setup
service and wait until it has completed, avoiding the race confdition.

Change-Id: I4ada8473bfd17b763bde16ac95099ddf7deb541c

playbooks/common-tasks/os-lxc-container-setup.yml

@@ -133,6 +133,14 @@
   tags:
     - common-lxc
 
+- name: Wait for container tmpfiles-setup finish
+  raw: systemctl status systemd-tmpfiles-setup.service | grep Process | grep 'code=exited' >/dev/null
+  register: systemd_tmpfiles
+  until: systemd_tmpfiles.rc == 0
+  retries: 20
+  delay: 2
+  changed_when: false
+
 - name: Wait for container connectivity
   wait_for_connection:
     connect_timeout: "{{ lxc_container_wait_params.connect_timeout | default(omit) }}"