Update Ceph instructions for Manila integrations

Author: MoteHue

docs/filesystems.md

@@ -1,6 +1,6 @@
 # Overview
 
-The Slurm appliance supports mounting shared filesystems using [CephFS](https://docs.ceph.com/en/latest/cephfs/) via [OpenStack Manila](https://docs.openstack.org/manila/latest/). These docs explain:
+The Slurm appliance supports mounting shared filesystems using [CephFS](https://docs.ceph.com/en/latest/cephfs/) via [OpenStack Manila](https://docs.openstack.org/manila/latest/). This section explains:
 
 - How to create the shares in OpenStack Manila.
 
@@ -18,7 +18,7 @@ If this is the first time Manila is being used on the system, a CephFS share typ
   openstack share type create cephfs-type false --extra-specs storage_protocol=CEPHFS vendor_name=Ceph
   ```
 
-Once this exists, create a share using credentials for the Slurm project. An access rule also needs to be created, where the `access_to` argument (`openstack share access create <share> <access_type> <access_to>`) is a user that will be created in Ceph. This needs to be globally unique in Ceph, so needs to be different for each OpenStack project.
+Once this exists, create a share using credentials for the Slurm project. An access rule also needs to be created, where the `access_to` argument (`openstack share access create <share> <access_type> <access_to>`) is a user that will be created in Ceph. This needs to be globally unique in Ceph, so needs to be different for each OpenStack project. Ideally, this share should include your environment name. In this example, the name is "production".
 
   ```bash
   openstack share create CephFS 300 --description 'Scratch dir for Slurm prod' --name slurm-production-scratch --share-type cephfs-type --wait
@@ -36,13 +36,23 @@ To mount shares onto hosts in a group, add them to the `manila` group.
   compute
   ```
 
-Set the version of Ceph which is running on the system.
+If you are running a different version of Ceph from the defaults in the i[os-manila-mount role](https://github.com/stackhpc/ansible-role-os-manila-mount/blob/master/defaults/main.yml), you will need to update the package version by setting the following.
 
   ```yaml
   # environments/site/inventory/group_vars/manila.yml:
   os_manila_mount_ceph_version: "18.2.4"
   ```
 
+This will need to be included in the `builder` group to be installed in the host image.
+
+  ```ini
+  # environments/site/inventory/groups:
+  [manila:children]:
+  login
+  compute
+  builder
+  ```
+
 Define the list of shares to be mounted, and the paths to mount them to. The example below parameterises the share name using the environment name. See the [stackhpc.os-manila-mount role](https://github.com/stackhpc/ansible-role-os-manila-mount) for further configuration options.
 
   ```yaml

environments/common/inventory/group_vars/all/manila.yml

@@ -10,4 +10,8 @@ os_manila_mount_shares: []
   #   mount_group:
   #   mount_mode:
 
-# os_manila_mount_ceph_version: nautilus # role default for RockyLinux 8
+# os_manila_mount_ceph_version:
+
+# Empty repo lists from stackhpc.ansible-role-os-manila-mount role defaults, as these repofiles are
+# now generated by dnf_repos to allow injecting Ark creds:
+os_manila_mount_ceph_rpm_repos: []