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Configuring OpenStack Cinder with Kubernetes

This guide will walk you through configuring OpenStack Cinder with Kubernetes. OpenStack Cinder is a block storage service that allows you to create persistent volumes for your Kubernetes cluster. After following this guide, you will be able to create persistent volumes backed by Cinder block storage.

We're using the official OpenStack documentation as a reference for this guide. You can find the official documentation here: Using Cinder CSI Plugin

Objectives​

  • Connect your Kubernetes cluster to OpenStack Cinder.
  • Create a storage class for your Kubernetes cluster.
  • Create a persistent volume claim (PVC) and persistent volume (PV) backed by Cinder.

Prerequisites​

Configure OpenStack Cinder​

Clone the CSI Cinder repository​

git clone https://github.com/kubernetes/cloud-provider-openstack && cd cloud-provider-openstack

Checkout the tag that matches your Kubernetes version. For example, if you're running Kubernetes 1.24.2, you would checkout the v1.24.2 tag.

git checkout tags/v1.24.2

Optional - Setup Cloud Config Secret​

If you followed our previous guide on installing the OpenStack Cloud Controller Manager, you should already a secret named cloud-config in the kube-system namespace.

Verify that the secret exists:

kubectl get secret -n kube-system cloud-config

If you have not already created this secret, please follow the steps here: Creating Application Secret to generate application credentials, format the config file, and create the secret.

Install the CSI Cinder controller plugin​

The manifests included to deploy the CSI Cinder controller plugin are located in the manifests/cinder-csi-plugin directory.

Before deploying the manifests, we're going to delete one of the manifests that is not needed for this guide. The csi-secret-cinderplugin.yaml manifest is used to create a secret that is used to authenticate with the OpenStack API. We will be using the cloud-config secret that we created in the previous step or already exists in your cluster.

Remove the csi-secret-cinderplugin.yaml manifest​

rm manifests/cinder-csi-plugin/csi-secret-cinderplugin.yaml

Deploy the CSI Cinder controller plugin​

kubectl -f manifests/cinder-csi-plugin/ apply

Verify the CSI Cinder pods are running​

This may take a few minutes to complete. If the pods do not start, please check the logs for any errors. A common error is that the cloud-config secret is not found or is incorrectly formatted.

kubectl get pods -n kube-system | grep csi-cinder

View CSI Drivers​

kubectl get csidrivers.storage.k8s.io

Output:

NAME                       ATTACHREQUIRED   PODINFOONMOUNT   STORAGECAPACITY   TOKENREQUESTS   REQUIRESREPUBLISH   MODES                  AGE
cinder.csi.openstack.org   true             true             false             <unset>         false               Persistent,Ephemeral   19h

Create a Cinder storage class​

A storage class is used to define the parameters that are used to create a persistent volume. The storage class is used to create a persistent volume claim (PVC) that is then used to create a persistent volume (PV). The PV is then used by a pod to store data.

kubectl apply -f - <<EOF
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: csi-sc-cinder
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
provisioner: cinder.csi.openstack.org
parameters:
  availability: nova
allowVolumeExpansion: true
volumeBindingMode: Immediate
EOF

Verify​

Create a persistent volume claim​

Now that we have a storage class, we can create a persistent volume claim (PVC). This will create a persistent volume (PV) that is backed by Cinder block storage.

In the previous step, we set the Cinder storage class as the default storage class. This means that we do not need to specify the storage class in the PVC. The storageClassName field is optional, but we've included it in the example below for clarity.

kubectl apply -f - <<EOF
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: test-volume
  namespace: default
spec:
  accessModes:
  - ReadWriteOnce
  storageClassName: csi-sc-cinder
  resources:
    requests:
      storage: 1Gi
EOF

Verify the PVC is created​

kubectl get pvc -A

OUTPUT:

NAMESPACE   NAME          STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS    AGE
default     test-volume   Bound    pvc-25cda9ab-6dfd-4aba-b629-f6c78d18cd05   1Gi        RWO            csi-sc-cinder   67m

Check OpenStack Cinder​

Verify that the volume was created in OpenStack Cinder. We can do this by logging into the OpenStack dashboard or by using the OpenStack CLI.

openstack volume list

Output:

+--------------------------------------+------------------------------------------+-----------+------+-------------+
| ID                                   | Name                                     | Status    | Size | Attached to |
+--------------------------------------+------------------------------------------+-----------+------+-------------+
| f88eb9fc-3919-4918-b94e-c7ec880eae92 | pvc-25cda9ab-6dfd-4aba-b629-f6c78d18cd05 | available |    1 |             |
+--------------------------------------+------------------------------------------+-----------+------+-------------+