Feature/nfs node pvc backend

[mvalsecc]

• The NFS VM provision bits are done
• nfs-subdir-external-provisioner provisioning logic is done

[mvalsecc]

Tasks left @mvalsecc

• The playbook in this PR works out of the box with Fedora32 and Rocky Linux 8.9, but it seems not to work with Fedora Server 39. I fiddled with it for a while, then I just settled on using Rocky Linux instead as per we spoke offline.
• Add the NFS server install and export setup tasks
• Remove unneeded comments
• Move most set_facts tasks to be parameters inside vars
• Include setup-openshift-install-nfs-subdir-external-provisioner.yaml after the cluster has been up and running
• confirm 03_cleanup.yaml removes all the storage VM related files
• confirm RockyOS download qcow2 file is downloaded only if ff_provision_storage is true
• Test with OKD as well

Things to double check @kazuhisya

• Choose the OS to use for the NFS server: Rocky Linux 8.9
• Decide how many GB do we want the NFS export to be (by default): 50
• Decide whether to use username/pwd or ssh-key access to the NFS node: both (root pwd hardcoded to root for cloud and root users)
• ff_provision_storage decides whether to deploy the NFS VM, and create the storageclass or not

Memo: Clean up tasks (to be implemented in another PR)

• Should I Update the image in the README.md to show the storage node as well?
• After this PR is merged, we do download quite a lot files on the first execution (as the NFS server needs another OS). I thought it might be a good idea to start tweaking the file download tasks (i.e. get_materials.yml to be async async. Let me know if I should do into this PR, on what!
• BONUS POINT: If we want to add some test code (as in an external "test-pvc.yaml", we can add a minimal app using a test claim, see if it spins up, and then delete it.): DONE (see tests folder)

  echo "Creating demo deployment in demo namespace..."
  kubectl create namespace demo 2>/dev/null
  kubectl apply -f ../resources/app/app_with_pvc_using_external_provisioner_storage_class.yaml -n demo
  

[mvalsecc]

One option would be to use this script to get the correct architecture helm binary. Up to you! @kazuhisya

$ curl -fsSL -o get_helm.sh https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3
$ chmod 700 get_helm.sh
$ ./get_helm.sh

[kazuhisya]

wip at 4ac5068