Keep persistent systemd journals

This patch enables persistent systemd journals and allows a deployer
to disable the option if needed. The disk space requirements are
extremely low since the files are stored in binary format. It is
significantly less storage than rsyslog requires.

Closes-Bug: 1748195
Change-Id: I4de267f2839c5022e83a07fa7779f242808df5c0

defaults/main.yml

@@ -144,3 +144,6 @@ opensuse_mirror_obs: "{{ opensuse_mirror }}"
 opensuse_repo_oss_url: "{{ opensuse_mirror }}/distribution/leap/{{ ansible_distribution_version }}/repo/oss/"
 opensuse_repo_update_url: "{{ opensuse_mirror }}/update/leap/{{ ansible_distribution_version }}/oss/"
 opensuse_obs_cloud_repo_url: "{{ opensuse_mirror_obs }}/repositories/Cloud:/OpenStack:/Pike/openSUSE_Leap_{{ ansible_distribution_version }}"
+
+# Keep a history of systemd journals on disk after reboots
+openstack_host_keep_journals: yes

handlers/main.yml

@@ -18,3 +18,9 @@
     name: "sysstat"
     state: "restarted"
     enabled: "yes"
+
+- name: Restart systemd-journald
+  service:
+    name: systemd-journald
+    state: restarted
+    enabled: yes

releasenotes/notes/persistend-systemd-journals-c1874b52ad666744.yaml

@@ -0,0 +1,10 @@
+---
+features:
+  - |
+    Persistent systemd journals are now enabled. This allows deployers to keep
+    older systemd journals on disk for review. The disk space requirements are
+    extremely low since the journals are stored in binary format. The default
+    location for persistent journals is in ``/var/log/journal``.
+
+    Deployers can opt out of this change by setting
+    ``openstack_host_keep_journals`` to ``no``.

tasks/configure_metal_hosts.yml

@@ -85,3 +85,24 @@
 - name: Configure sysstat
   include: openstack_sysstat.yml
   when: openstack_host_sysstat_enabled | bool
+
+- name: Create a directory to hold systemd journals on disk
+  file:
+    path: /var/log/journal
+    state: directory
+  register: journald_directory
+  when:
+    - openstack_host_keep_journals | bool
+
+# NOTE(mhayden): The linter is skipped here since the command does not create
+# any files. The command ensures that proper permissions and SELinux contests
+# are set.
+- name: Create tmpfiles structure in journald directory
+  command: systemd-tmpfiles --create --prefix /var/log/journal
+  when:
+    - journald_directory | changed
+    - openstack_host_keep_journals | bool
+  notify:
+    - Restart systemd-journald
+  tags:
+    - skip_ansible_lint