openafs-client: add service timeout override

Starting the openafs-client service is an intensive operation as it
walks the cache registering various things.  We've seen on our
production ARM64 mirror this can take longer than the 1:30 default
timeout.  This is a fatal issue, as the module will try to unload
while afsd is still spinning and working resulting in completely
corrupt kernel state.

This is about double the longest time we've seen, so should give
plenty of overhead.

Change-Id: I37186494b9afd72eab3a092279579f1a5fa5d22c

roles/openafs-client/README.rst

@@ -43,3 +43,10 @@ role has limited platform support.  Currently supported are
    :default: no
 
    Enable or disable gpg checking for ``openafs_yum_repo_url``
+
+.. zuul:rolevar:: openafs_client_service_timeout_sec
+   :default: 480
+
+   The TimeoutSec for service start.  Accounting for the cache
+   during startup can cause a high load which may necessitate
+   a longer startup timeout on some platforms.

roles/openafs-client/defaults/main.yaml

@@ -1,3 +1,4 @@
 openafs_client_cell: 'openstack.org'
 openafs_client_cache_directory: '/var/cache/openafs'
-openafs_client_cache_size: 500000
+openafs_client_cache_size: 500000
+openafs_client_service_timeout_sec: 480

roles/openafs-client/tasks/main.yaml

@@ -62,6 +62,23 @@
     mode: 0700
   become: yes
 
+- name: Set timeout override
+  become: yes
+  block:
+    - name: Create service override directory
+      file:
+        path: '/etc/systemd/system/openafs-client.service.d'
+        state: directory
+        owner: root
+        group: root
+        mode: 0755
+    - name: Save override
+      template:
+        dest: '/etc/systemd/system/openafs-client.service.d/timeout.conf'
+        src: 'timeout.conf.j2'
+        group: root
+        mode: 0644
+
 - name: Setup OS specific openafs-client environment
   include_tasks: "{{ lookup('first_found', params) }}"
   vars:

roles/openafs-client/templates/timeout.conf.j2

@@ -0,0 +1,2 @@
+[Service]
+TimeoutSec={{ openafs_client_service_timeout_sec }}