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OpenShift Data Foundation with ARO

Kevin Collins

06/28/2022

Note: This guide demonstrates how to setup and configure self-managed OpenShift Data Foundation in Internal Mode on an ARO Cluster and test it out.

Prerequisites

An Azure Red Hat OpenShift cluster ( verion 4.10+ )
kubectl cli
oc cli
moreutils (sponge)
jq

Install compute nodes for ODF

A best practice for optimal performance is to run ODF on dedicated nodes with a minimum of one per zone. In this guide, we will be provisioning 3 additional compute nodes, one per zone. Run the following script to create the additional nodes:

Log into your ARO Cluster

Create the new compute nodes

 for ZONE in 1 2 3
   do
     item=$((ZONE-1))
     MACHINESET=$(oc get machineset -n openshift-machine-api -o=jsonpath="{.items[$item]}" | jq -r '[.metadata.name] | @tsv')
     oc get machineset -n openshift-machine-api $MACHINESET -o json > default_machineset$ZONE.json
     worker=odf-worker-$ZONE
     jq ".metadata.name = \"$worker\"" default_machineset$ZONE.json | sponge default_machineset$ZONE.json
     jq '.spec.replicas = 1' default_machineset$ZONE.json| sponge default_machineset$ZONE.json
     jq ".spec.selector.matchLabels.\"machine.openshift.io/cluster-api-machineset\" = \"$worker\"" default_machineset$ZONE.json| sponge default_machineset$ZONE.json
     jq ".spec.template.metadata.labels.\"machine.openshift.io/cluster-api-machineset\" = \"$worker\"" default_machineset$ZONE.json| sponge default_machineset$ZONE.json
     jq '.spec.template.spec.providerSpec.value.vmSize = "Standard_D16s_v3"' default_machineset$ZONE.json | sponge default_machineset$ZONE.json
     jq ".spec.template.spec.providerSpec.value.zone = \"$ZONE\"" default_machineset$ZONE.json | sponge default_machineset$ZONE.json
     jq 'del(.status)' default_machineset$ZONE.json | sponge default_machineset$ZONE.json
     oc create -f default_machineset$ZONE.json
 done

Label new compute nodes

It takes just a couple of minutes for new nodes to appear.

Check if the nodes are ready:

oc get nodes | grep odf-worker

expected output:

odf-worker-1-jg7db                                  Ready    worker   19h     v1.23.5+3afdacb
odf-worker-2-ktvct                                  Ready    worker   19h     v1.23.5+3afdacb
odf-worker-3-rk22b                                  Ready    worker   19h     v1.23.5+3afdacb

Once you see the three nodes, the next step we need to do is label and taint the nodes. This will ensure the OpenShift Data Foundation is installed on these nodes and no other workload will be placed on the nodes.

for worker in $(oc get nodes | grep odf-worker | awk '{print $1}')
do
  oc label node $worker cluster.ocs.openshift.io/openshift-storage=``
  oc adm taint nodes $worker node.ocs.openshift.io/storage=true:NoSchedule
done

Deploy OpenShift Data Foundation

Next, we will install OpenShift Data Foundation via an Operator.

Create the openshift-storage namespace

cat <<EOF | oc apply -f -
apiVersion: v1
kind: Namespace
metadata:
  labels:
    openshift.io/cluster-monitoring: "true"
  name: openshift-storage
spec: {}
EOF

Create the Operator Group for openshift-storage ```bash cat «EOF | oc apply -f - apiVersion: operators.coreos.com/v1 kind: OperatorGroup metadata: name: openshift-storage-operatorgroup namespace: openshift-storage spec: targetNamespaces:
- openshift-storage EOF ```

Subscribe to the ocs-operator

cat <<EOF | oc apply -f -
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: ocs-operator
  namespace: openshift-storage
spec:
  channel: "stable-4.10"  # <-- Channel should be modified depending on the OCS version to be installed. Please ensure to maintain compatibility with OCP version
  installPlanApproval: Automatic
  name: ocs-operator
  source: redhat-operators  # <-- Modify the name of the redhat-operators catalogsource if not default
  sourceNamespace: openshift-marketplace
EOF

Subscribe to the odf-operator

cat <<EOF | oc apply -f -
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: odf-operator
  namespace: openshift-storage
spec:
  channel: "stable-4.10" # <-- Channel should be modified depending on the OCS version to be installed. Please ensure to maintain compatibility with OCP version
  installPlanApproval: Automatic
  name: odf-operator
  source: redhat-operators  # <-- Modify the name of the redhat-operators catalogsource if not default
  sourceNamespace: openshift-marketplace
EOF

Create a Storage Cluster ```bash cat «EOF | oc apply -f - apiVersion: ocs.openshift.io/v1 kind: StorageCluster metadata: annotations: uninstall.ocs.openshift.io/cleanup-policy: delete uninstall.ocs.openshift.io/mode: graceful generation: 2 name: ocs-storagecluster namespace: openshift-storage spec: storageDeviceSets:
- config: {} count: 1 dataPVCTemplate: spec: accessModes: - ReadWriteOnce resources: requests: storage: 2Ti storageClassName: managed-premium volumeMode: Block name: ocs-deviceset-managed-premium portable: true replica: 3 version: 4.10.0 EOF ```

Validate the install

List the cluster service version for the ODF operators

oc get csv -n openshift-storage

verify that the operators below have succeeded.

NAME                  DISPLAY                       VERSION   REPLACES   PHASE
mcg-operator.v4.10.4   NooBaa Operator               4.10.4                Succeeded
ocs-operator.v4.10.4   OpenShift Container Storage   4.10.4                Succeeded
odf-operator.v4.10.4   OpenShift Data Foundation     4.10.4                Succeeded

Check that the ocs storage classes have been created

note: this can take around 5 minutes

oc get sc

NAME                          PROVISIONER                             RECLAIMPOLICY   VOLUMEBINDINGMODE      ALLOWVOLUMEEXPANSION   AGE
managed-csi                   disk.csi.azure.com                      Delete          WaitForFirstConsumer   true                   118m
managed-premium (default)     kubernetes.io/azure-disk                Delete          WaitForFirstConsumer   true                   119m
ocs-storagecluster-ceph-rbd   openshift-storage.rbd.csi.ceph.com      Delete          Immediate              true                   7s
ocs-storagecluster-cephfs     openshift-storage.cephfs.csi.ceph.com   Delete          Immediate              true                   7s

Test it out

To test out ODF, we will create ‘writer’ pods on each node across all zones and then a reader pod to read the data that is written. This will prove both regional storage along with “read write many” mode is working correctly.

Create a new project
```
oc new-project odf-demo
```

Create a RWX Persistent Volume Claim for ODF

cat <<EOF | kubectl apply -f -
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: standard
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 400Gi
  storageClassName: ocs-storagecluster-cephfs
EOF

Create writer pods via a DaemonSet Using a deamonset will ensure that we have a ‘writer pod’ on each worker node and will also prove that we correctly set a taint on the ‘ODF Workers’ where which we do not want workload to be added to.

The writer pods will write out which worker node the pod is running on, the data, and a hello message.

cat <<EOF | oc apply -f -
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: test-odf
  labels:
    app: test-odf
spec:
  selector:
    matchLabels:
      name: test-odf
  template:
    metadata:
      labels:
        name: test-odf
    spec:
      containers:
        - name: azodf
          image: centos:latest
          command: ["sh", "-c"]
          resources:
            limits:
              cpu: 1
              memory: "1Gi"
          args:
            [
              "while true; do printenv --null NODE_NAME | tee -a /mnt/odf-data/verify-odf; echo ' says hello '$(date) | tee -a /mnt/odf-data/verify-odf; sleep 15; done;",
            ]
          volumeMounts:
            - name: odf-vol
              mountPath: "/mnt/odf-data"
          env:
            - name: NODE_NAME
              valueFrom:
                fieldRef:
                  fieldPath: spec.nodeName
      volumes:
        - name: odf-vol
          persistentVolumeClaim:
            claimName: standard
EOF

Check the writer pods are running.

note: there should be 1 pod per non-ODF worker node
oc get pods

expected output

NAME             READY   STATUS    RESTARTS   AGE    IP            NODE                                   NOMINATED NODE   READINESS GATES
test-odf-47p2g   1/1     Running   0          107s   10.128.2.15   aro-kmobb-7zff2-worker-eastus1-xgksq   <none>           <none>
test-odf-p5xk6   1/1     Running   0          107s   10.131.0.18   aro-kmobb-7zff2-worker-eastus3-h4gv7   <none>           <none>
test-odf-ss8b5   1/1     Running   0          107s   10.129.2.32   aro-kmobb-7zff2-worker-eastus2-sbfpm   <none>           <none>

Create a reader pod The reader pod will simply log data written by the writer pods.

cat <<EOF | oc apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: test-odf-read
spec:
  containers:
    - name: test-odf-read
      image: centos:latest
      command: ["/bin/bash", "-c", "--"]
      resources:
        limits:
          cpu: 1
          memory: "1Gi"
      args: ["tail -f /mnt/odf-data/verify-odf"]
      volumeMounts:
        - name: odf-vol
          mountPath: "/mnt/odf-data"
  volumes:
    - name: odf-vol
      persistentVolumeClaim:
        claimName: standard
EOF

Now let’s verify the POD is reading from shared volume.

oc logs test-odf-read
aro-kmobb-7zff2-worker-eastus1-xgksq says hello Wed Jun 29 10:41:06 EDT 2022
aro-kmobb-7zff2-worker-eastus3-h4gv7 says hello Wed Jun 29 10:41:06 EDT 2022
aro-kmobb-7zff2-worker-eastus2-sbfpm says hello Wed Jun 29 10:41:06 EDT 2022
aro-kmobb-7zff2-worker-eastus1-xgksq says hello Wed Jun 29 10:41:06 EDT 2022
aro-kmobb-7zff2-worker-eastus3-h4gv7 says hello Wed Jun 29 10:41:06 EDT 2022
aro-kmobb-7zff2-worker-eastus2-sbfpm says hello Wed Jun 29 10:41:06 EDT 2022
aro-kmobb-7zff2-worker-eastus1-xgksq says hello Wed Jun 29 10:41:06 EDT 2022
aro-kmobb-7zff2-worker-eastus3-h4gv7 says hello Wed Jun 29 10:41:06 EDT 2022

Notice that pods in different zones are writing to the PVC which is managed by ODF.