Bug 1929136: OpenStack: document Manila share mounting

docs/user/openstack/connect_nodes_to_manila_network.md

@@ -0,0 +1,35 @@
+# Connecting nodes to a dedicated Manila network
+
+Depending on your OpenStack platform configuration, it is very likely that Manila uses a dedicated network for its shares. When that is the case, you need to attach your OpenShift compute nodes to this network otherwise pods might fail to mount the shares, as shown in the following example:
+
+```txt
+Mounting command: mount
+Mounting arguments: -t nfs 172.16.32.1:/volumes/_nogroup/891cb5d9-a417-43a5-9d1c-5b160a16e7be /var/lib/kubelet/pods/c36e7573-853a-44f9-99bd-0de630edb3b9/volumes/kubernetes.io~csi/pvc-6b632043-2580-4ada-a634-ae696db4b96c/mount
+Output: mount.nfs: Connection timed out
+```
+
+To connect your workers at the time of installation you can use [additionalNetworkIDs](https://github.com/openshift/installer/blob/master/docs/user/openstack/customization.md#additional-networks) parameter in the install config and set Manila network ID there:
+
+Example OpenShift install config:
+
+```yaml
+...
+compute:
+- name: worker
+  platform:
+    openstack:
+      additionalNetworkIDs:
+      - <manila_network_id>
+...
+```
+
+As day2 operation you need to add new network at `networks` section of your machineset's [provider spec](https://github.com/openshift/installer/blob/master/docs/user/openstack/README.md#defining-a-machineset-that-uses-multiple-networks). After that Cluster API Provider OpenStack will automatically connect your workers to the network.
+
+Example of OpenStack Machine Spec:
+
+```yaml
+networks:
+  ...
+  - uuid: <manila_network_id>
+  ...
+```