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Deployment Guide—Dell EMC Ready Stack for Red Hat OpenShift Container Platform 4.6
Provisioning Storage
Introduction Prerequisites Unity XT storage PowerMax storage PowerScale storage OpenShift Container storage

OpenShift Container storage

  • Red Hat provides OpenShift container storage as a method to provision storage to pods using local devices in compute nodes.

    Prerequisites include:

    • Minimum of three compute nodes in the OpenShift cluster.
    • Disk size is the same across all compute nodes.
    • No partitions are configured.
    • Additional steps for Red Hat Enterprise Linux-based compute nodes, as described in the following section.

    Perform these steps in all Red Hat Enterprise Linux-based compute nodes.

    1. Ensure that the rhel-7-server-rpms and rhel-7-server-extras-rpms repositories are enabled. To enable Red Hat subscription, see Step 3.substep c in Preparing the CSAH node in this guide:

    [root@compute-3 ~]# subscription-manager repos --enable=rhel-7-server-rpms

    Repository 'rhel-7-server-rpms' is enabled for this system.

    [root@compute-3 ~]# subscription-manager repos --enable=rhel-7-server-extras-rpms

    Repository 'rhel-7-server-extras-rpms' is enabled for this system.

    1. Install RPMs:

    [root@compute-3 ~]# yum install -y policycoreutils container-selinux

    1. Set selinux permissions:

    [root@compute-3 ~]# setsebool -P container_use_cephfs on

    Install OpenShift Container Storage Operator

    1. From the OpenShift console, select Operators > OperatorHub and search for OpenShift Container Storage.
    1. Ensure the version that is displayed is 4.6, and then click the Install option.

    Note: Project openshift-storage is created automatically. Installed operators are listed under Operators > Installed Operators.

    1. Verify that the OCS operator pods are running:

    [core@csah ocs]$ oc get pods -n openshift-storage -o wide

    NAME                                   READY   STATUS    RESTARTS   AGE     IP             NODE                    NOMINATED NODE   READINESS GATES

    noobaa-operator-55c779bc76-tb4dr       1/1     Running   0          3m34s   10.131.1.232   compute-2.example.com   <none>           <none>

    ocs-metrics-exporter-b5df77d68-bs5wg   1/1     Running   0          3m34s   10.129.2.54    compute-3.example.com   <none>           <none>

    ocs-operator-6dfd764558-lwzqq          1/1     Running   0          3m34s   10.128.3.154   compute-1.example.com   <none>           <none>

    rook-ceph-operator-64cc69dbcc-gf29x    1/1     Running   0          3m34s   10.131.1.231   compute-2.example.com   <none>           <none>

    Install the Local Storage Operator

    1. Log in to the OpenShift console. See Accessing the OpenShift web console for instructions. Select Operators > OperatorHub.
    1. Search for Local Storage and select it.
    2. Ensure that the version is displayed as 4.6, and then click the Install option.

    Note: Project openshift-local-storage is created automatically. Installed operators are listed under Operators -> Installed Operators.

    1. Verify that the local storage operator pod is running:

    [core@csah ocs]$ oc get pods -n openshift-local-storage -o wide

    NAME                                     READY   STATUS    RESTARTS   AGE     IP             NODE                    NOMINATED NODE   READINESS GATES

    local-storage-operator-967d7f899-gl2qw   1/1     Running   0          6m33s   10.128.3.159   compute-1.example.com   <none>           <none>

    Create the OpenShift Container Storage cluster

    1. Log in to the OpenShift console. See Accessing the OpenShift web console for instructions. Select Operators > Installed Operators > OpenShift Container Storage.
    1. Under Details > Storage Cluster, click Create Instance.
    2. Ensure that Project is set to openshift-storage. Under Select Mode, select Internal – Attached Devices, then select the appropriate number of compute nodes (a minimum of three), and click Next.

    A volume set is created by default by adding all available disks under all compute nodes.

    1. Specify a name for the volume set. By default, a storage class with a similar name is created.
    2. Select the compute nodes, click Advanced, specify a size limit under Disk Size, and click Next.

    Note: In our deployment, we used only SSD/NVMe drives by setting the size to 700 G to 900 G.

    1. Click the drop-down menu in Storage Class and select the storage class that was created automatically in step 4. Click Create after the appropriate nodes are displayed under Nodes.
    2. Verify that the storage class is created and all pods in the openshift-storage and openshift-local-storage projects are either in a Running or Completed state:

    [core@csah ocs]$ oc get sc | grep <storage class name>

    Note: The ocs-storagecluster-ceph-rbd, ocs-storagecluster-ceph-rgw, ocs-storagecluster-cephfs storage classes are created by default.

    [core@csah ocs]$ oc get pods -n openshift-storage

    [core@csah ocs]$ oc get pods -n openshift-local-storage

    Create Cephfs PVC

    The following steps create a PVC by using ocs-storagecluster-cephfs and ocs-storagecluster-ceph-rbdL:

    1. Create a YAML file to create a PVC using the ocs-storagecluster-cephfs storage class (for guidance, see this sample file in GitHub).

    [core@csah ~]$ oc create -f <YAML file>

    1. Verify that the volume is created:

    [core@csah ocs]$ oc get pvc -n ocs

    NAME       STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS                AGE

    ocsfspvc   Bound    pvc-44d3a805-0e6b-48b1-a8d6-0ab6c56e1975   10Gi       RWX            ocs-storagecluster-cephfs   29s

    1. Create a pod and attach the volume (see this sample file in GitHub).

    [core@csah ~]$ oc create -f <YAML file>

    1. Validate that the pod is created and the volume is attached:

    [core@csah ocs]$ oc exec -it -n ocs ocsfspod -- df -h /usr/share/nginx/html

    Filesystem                                                                                                                                               Size  Used Avail Use% Mounted on

    172.30.64.242:6789,172.30.152.143:6789,172.30.10.82:6789:/volumes/csi/csi-vol-5799b028-4e0f-11eb-b2ab-0a580a8003a8/1021f0b6-5b98-4d33-81e6-cdcecd668345   10G     0   10G   0% /usr/share/nginx/html

    Create Ceph rbd PVC

    1. Create a YAML file with which to create a PVC by using the ocs-storagecluster-ceph-rbd storage class (see this sample file in GitHub).

    [core@csah ~]$ oc create -f <YAML file>

    1. Verify that the PVC is created successfully:

    [core@csah ocs]$ oc get pvc ocsrbdpvc -n ocs

    NAME        STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS                  AGE

    ocsrbdpvc   Bound    pvc-7742925d-8ecb-4d49-8b4b-00313d8d7c85   10Gi       RWO            ocs-storagecluster-ceph-rbd   27s

    1. Create a pod and attach the volume (see this sample file in GitHub).

    [core@csah ~]$ oc create -f <YAML file>

    1. Verify that the pod is created and the volume is attached:

    [core@csah ocs]$ oc exec -it ocsrbdpod -n ocs -- df -h /usr/share/nginx/html

    Filesystem      Size  Used Avail Use% Mounted on /dev/rbd1       9.8G   37M  9.8G   1% /usr/share/nginx/html