Chapter 16. Creating exports using NFS
Chapter 16. Creating exports using NFS This section describes how to create exports using NFS that can then be accessed externally from the OpenShift cluster. Follow the instructions below to create exports and access them externally from the OpenShift Cluster: Section 16.1, "Enabling the NFS feature" Section 16.2, "Creating NFS exports" Section 16.3, "Consuming NFS exports in-cluster" Section 16.4, "Consuming NFS exports externally from the OpenShift cluster" 16.1. Enabling the NFS feature To use NFS feature, you need to enable it in the storage cluster using the command-line interface (CLI) after the cluster is created. You can also enable the NFS feature while creating the storage cluster using the user interface. Prerequisites OpenShift Data Foundation is installed and running in the openshift-storage namespace. The OpenShift Data Foundation installation includes a CephFilesystem. Procedure Run the following command to enable the NFS feature from CLI: Verification steps NFS installation and configuration is complete when the following conditions are met: The CephNFS resource named ocs-storagecluster-cephnfs has a status of Ready . Check if all the csi-nfsplugin-* pods are running: Output has multiple pods. For example: 16.2. Creating NFS exports NFS exports are created by creating a Persistent Volume Claim (PVC) against the ocs-storagecluster-ceph-nfs StorageClass. You can create NFS PVCs two ways: Create NFS PVC using a yaml. The following is an example PVC. Note volumeMode: Block will not work for NFS volumes. <desired_name> Specify a name for the PVC, for example, my-nfs-export . The export is created once the PVC reaches the Bound state. Create NFS PVCs from the OpenShift Container Platform web console. Prerequisites Ensure that you are logged into the OpenShift Container Platform web console and the NFS feature is enabled for the storage cluster. Procedure In the OpenShift Web Console, click Storage Persistent Volume Claims Set the Project to openshift-storage . Click Create PersistentVolumeClaim . Specify Storage Class , ocs-storagecluster-ceph-nfs . Specify the PVC Name , for example, my-nfs-export . Select the required Access Mode . Specify a Size as per application requirement. Select Volume mode as Filesystem . Note: Block mode is not supported for NFS PVCs Click Create and wait until the PVC is in Bound status. 16.3. Consuming NFS exports in-cluster Kubernetes application pods can consume NFS exports created by mounting a previously created PVC. You can mount the PVC one of two ways: Using a YAML: Below is an example pod that uses the example PVC created in Section 16.2, "Creating NFS exports" : <pvc_name> Specify the PVC you have previously created, for example, my-nfs-export . Using the OpenShift Container Platform web console. Procedure On the OpenShift Container Platform web console, navigate to Workloads Pods . Click Create Pod to create a new application pod. Under the metadata section add a name. For example, nfs-export-example , with namespace as openshift-storage . Under the spec: section, add containers: section with image and volumeMounts sections: For example: Under the spec: section, add volumes: section to add the NFS PVC as a volume for the application pod: For example: 16.4. Consuming NFS exports externally from the OpenShift cluster NFS clients outside of the OpenShift cluster can mount NFS exports created by a previously-created PVC. Procedure After the nfs flag is enabled, singe-server CephNFS is deployed by Rook. You need to fetch the value of the ceph_nfs field for the nfs-ganesha server to use in the step: For example: Expose the NFS server outside of the OpenShift cluster by creating a Kubernetes LoadBalancer Service. The example below creates a LoadBalancer Service and references the NFS server created by OpenShift Data Foundation. Replace <my-nfs> with the value you got in step 1. Collect connection information. The information external clients need to connect to an export comes from the Persistent Volume (PV) created for the PVC, and the status of the LoadBalancer Service created in the step. Get the share path from the PV. Get the name of the PV associated with the NFS export's PVC: Replace <pvc_name> with your own PVC name. For example: Use the PV name obtained previously to get the NFS export's share path: Get an ingress address for the NFS server. A service's ingress status may have multiple addresses. Choose the one desired to use for external clients. In the example below, there is only a single address: the host name ingress-id.somedomain.com . Connect the external client using the share path and ingress address from the steps. The following example mounts the export to the client's directory path /export/mount/path : If this does not work immediately, it could be that the Kubernetes environment is still taking time to configure the network resources to allow ingress to the NFS server.
oc --namespace openshift-storage patch storageclusters.ocs.openshift.io ocs-storagecluster --type merge --patch '{"spec": {"nfs":{"enable": true}}}' -n openshift-storage describe cephnfs ocs-storagecluster-cephnfs -n openshift-storage get pod | grep csi-nfsplugin csi-nfsplugin-47qwq 2/2 Running 0 10s csi-nfsplugin-77947 2/2 Running 0 10s csi-nfsplugin-ct2pm 2/2 Running 0 10s csi-nfsplugin-provisioner-f85b75fbb-2rm2w 2/2 Running 0 10s csi-nfsplugin-provisioner-f85b75fbb-8nj5h 2/2 Running 0 10s apiVersion: v1 kind: PersistentVolumeClaim metadata: name: <desired_name> spec: accessModes: - ReadWriteOnce resources: requests: storage: 1Gi storageClassName: ocs-storagecluster-ceph-nfs apiVersion: v1 kind: Pod metadata: name: nfs-export-example spec: containers: - name: web-server image: nginx volumeMounts: - name: nfs-export-pvc mountPath: /var/lib/www/html volumes: - name: nfs-export-pvc persistentVolumeClaim: claimName: <pvc_name> readOnly: false apiVersion: v1 kind: Pod metadata: name: nfs-export-example namespace: openshift-storage spec: containers: - name: web-server image: nginx volumeMounts: - name: <volume_name> mountPath: /var/lib/www/html apiVersion: v1 kind: Pod metadata: name: nfs-export-example namespace: openshift-storage spec: containers: - name: web-server image: nginx volumeMounts: - name: nfs-export-pvc mountPath: /var/lib/www/html volumes: - name: <volume_name> persistentVolumeClaim: claimName: <pvc_name> volumes: - name: nfs-export-pvc persistentVolumeClaim: claimName: my-nfs-export oc get pods -n openshift-storage | grep rook-ceph-nfs oc describe pod <name of the rook-ceph-nfs pod> | grep ceph_nfs oc describe pod rook-ceph-nfs-ocs-storagecluster-cephnfs-a-7bb484b4bf-bbdhs | grep ceph_nfs ceph_nfs=my-nfs apiVersion: v1 kind: Service metadata: name: rook-ceph-nfs-ocs-storagecluster-cephnfs-load-balancer namespace: openshift-storage spec: ports: - name: nfs port: 2049 type: LoadBalancer externalTrafficPolicy: Local selector: app: rook-ceph-nfs ceph_nfs: <my-nfs> instance: a oc get pvc <pvc_name> --output jsonpath='{.spec.volumeName}' pvc-39c5c467-d9d3-4898-84f7-936ea52fd99d get pvc pvc-39c5c467-d9d3-4898-84f7-936ea52fd99d --output jsonpath='{.spec.volumeName}' pvc-39c5c467-d9d3-4898-84f7-936ea52fd99d oc get pv pvc-39c5c467-d9d3-4898-84f7-936ea52fd99d --output jsonpath='{.spec.csi.volumeAttributes.share}' /0001-0011-openshift-storage-0000000000000001-ba9426ab-d61b-11ec-9ffd-0a580a800215 oc -n openshift-storage get service rook-ceph-nfs-ocs-storagecluster-cephnfs-load-balancer --output jsonpath='{.status.loadBalancer.ingress}' [{"hostname":"ingress-id.somedomain.com"}] mount -t nfs4 -o proto=tcp ingress-id.somedomain.com:/0001-0011-openshift-storage-0000000000000001-ba9426ab-d61b-11ec-9ffd-0a580a800215 /export/mount/path