DO120 - ch02s06

Bookmark this page

Guided Exercise: Configure Additional Storage Classes

Deploy a database that uses guaranteed high IOPS storage.

Outcomes

Inspect the Amazon Elastic Block Store (EBS) volume types that the nodes of a Red Hat OpenShift on AWS (ROSA) cluster use.
List the existing storage classes.
Create storage classes for I/O-intensive workloads.
Configure OpenShift workloads to request volumes of a specific storage class.

To perform this exercise, ensure that you have completed the section called “Guided Exercise: Configure Developer Self-service for a ROSA Cluster ”.

Procedure 2.3. Instructions

Verify that you are logged in to your ROSA cluster from the OpenShift CLI.
1. Open a command-line terminal on your system, and then run the oc whoami command to verify your connection to the ROSA cluster. If the command succeeds, then skip to the next step.
```
$ oc whoami
wlombardogh
```
  The username is different in your command output.
2. If the command returns an error, then reconnect to your ROSA cluster. Run the rosa describe cluster command to retrieve the URL of the OpenShift web console.
```
$ rosa describe cluster --cluster do120-cluster
...output omitted...
Console URL:     https://console-openshift-console.apps.do120-cluster.jf96.p1.openshiftapps.com
...output omitted...
```
  The URL in the preceding output is different on your system.
3. Open a web browser, and then navigate to the OpenShift web console URL. Click github-do120. If you are not already logged in to GitHub, then provide your GitHub credentials.
4. Click your name in the upper right corner of the web console, and then click Copy login command. If the login page is displayed, then click github-do120 and use your GitHub credentials for authentication.
5. Click Display Token, and then copy the oc login --token command to the clipboard.
6. Paste the command into the command-line terminal, and then run the command.
```
$ oc login --token=sha256~1NofZkVCi3qCBcBJGc6XiOJTK5SDXF2ZYwhAARx5yJg
  --server=https://api.do120-cluster.jf96.p1.openshiftapps.com:6443
Logged into "https://api.do120-cluster.jf96.p1.openshiftapps.com:6443" as "wlombardogh" using the token provided.
...output omitted...
```
  In the preceding command, the token and the URL are different on your system.

Review the EBS volume type that the cluster machines use for their disks.

List the machine resources in the openshift-machine-api namespace. Machine resources describe the hosts that the cluster nodes use. The machine names include the infra, master, or worker node types.

$ oc get machine -n openshift-machine-api
NAME                                         PHASE     TYPE         REGION    ...
do120-cluster-c8drv-infra-us-east-1a-qjw9w   Running   r5.xlarge    us-east-1 ...
do120-cluster-c8drv-infra-us-east-1a-rrm6c   Running   r5.xlarge    us-east-1 ...
do120-cluster-c8drv-master-0                 Running   m5.2xlarge   us-east-1 ...
do120-cluster-c8drv-master-1                 Running   m5.2xlarge   us-east-1 ...
do120-cluster-c8drv-master-2                 Running   m5.2xlarge   us-east-1 ...
do120-cluster-c8drv-worker-us-east-1a-brnvp  Running   m5.xlarge    us-east-1 ...
do120-cluster-c8drv-worker-us-east-1a-tnhfn  Running   m5.xlarge    us-east-1 ...

The machine names in the preceding output are different on your system.

Select one of the control plane machines from the preceding list, and then retrieve its block device parameters. Control plane machines have the master keyword in their names. The machine uses the gp3 EBS volume type.

On a Microsoft Windows system, replace the line continuation character (\) in the following long command with the backtick (`) character, which is the line continuation character in PowerShell.

$ oc get machine do120-cluster-c8drv-master-0 -n openshift-machine-api \
  -o jsonpath-as-json="{.spec.providerSpec.value.blockDevices}"
[
    [
        {
            "ebs": {
                "encrypted": true,
                "iops": 0,
                "kmsKey": {
                    "arn": ""
                },
                "volumeSize": 350,
                "volumeType": "gp3"
            }
        }
    ]
]

Retrieve the block device parameters of one of the infrastructure machines. The machine also uses the gp3 EBS volume type.

$ oc get machine do120-cluster-c8drv-infra-us-east-1a-qjw9w \
  -n openshift-machine-api \
  -o jsonpath-as-json="{.spec.providerSpec.value.blockDevices}"
[
    [
        {
            "ebs": {
                "encrypted": true,
                "iops": 0,
                "kmsKey": {
                    "arn": ""
                },
                "volumeSize": 300,
                "volumeType": "gp3"
            }
        }
    ]
]

Retrieve the block device parameters of one of the worker machines. The machine also uses the gp3 EBS volume type.

$ oc get machine do120-cluster-c8drv-worker-us-east-1a-brnvp \
  -n openshift-machine-api \
  -o jsonpath-as-json="{.spec.providerSpec.value.blockDevices}"
[
    [
        {
            "ebs": {
                "encrypted": true,
                "iops": 0,
                "kmsKey": {
                    "arn": ""
                },
                "volumeSize": 300,
                "volumeType": "gp3"
            }
        }
    ]
]

You organization plans to deploy an I/O-intensive MariaDB database. That workload requires an EBS volume of the io1 type. Verify that no existing storage class provides this type, and that your AWS Region supports it.

List the storage classes in your cluster. Notice that only the gp2 and gp3 types are available.

$ oc get sc
NAME            PROVISIONER             RECLAIMPOLICY   VOLUMEBINDINGMODE    ...
gp2             kubernetes.io/aws-ebs   Delete          WaitForFirstConsumer ...
gp2-csi         ebs.csi.aws.com         Delete          WaitForFirstConsumer ...
gp3 (default)   ebs.csi.aws.com         Delete          WaitForFirstConsumer ...
gp3-csi         ebs.csi.aws.com         Delete          WaitForFirstConsumer ...

List the availability zones in your AWS Region.

$ aws ec2 describe-availability-zones --query "AvailabilityZones[].ZoneName"
[
    "us-east-1a",
    "us-east-1b",
    "us-east-1c",
    "us-east-1d",
    "us-east-1e",
    "us-east-1f"
]

The availability zones in the preceding output depend on your AWS Region, and might be different on your system.

Create an EBS volume of the io1 type in dry mode to verify that the AWS Region supports this type. Use one of the availability zone for the --availability-zone option.

$ aws ec2 create-volume --dry-run --volume-type io1 --size 20 --iops 1000 \
  --availability-zone us-east-1a

An error occurred (DryRunOperation) when calling the CreateVolume operation: Request would have succeeded, but DryRun flag is set.

Create the io1-50 storage class.
1. Download the io1-50.yaml resource file at https://raw.githubusercontent.com/RedHatTraining/DO12X-apps/main/ROSA/configure-storage/io1-50.yaml.
2. Review the io1-50.yaml file. You do not have to change its contents. The storage class uses the ebs.csi.aws.com provisioner to request EBS volumes of the io1 type, with a maximum of 50 I/Os per second per GiB. For example, for a 4 GiB volume, the maximum IOPS is 200 (4 x 50).
```
---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: io1-50
provisioner: ebs.csi.aws.com
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: true
parameters:
  csi.storage.k8s.io/fstype: ext4
  type: io1
  iopsPerGB: "50"
  encrypted: "true"
```
3. Use the oc apply command to create the storage class resource from the io1-50.yaml file.
```
$ oc apply -f io1-50.yaml
storageclass.storage.k8s.io/io1-50 created
```
4. Verify that the storage class is available.
```
$ oc get sc io1-50
NAME        PROVISIONER       RECLAIMPOLICY   VOLUMEBINDINGMODE    ...
io1-50      ebs.csi.aws.com   Delete          WaitForFirstConsumer ...
```

Create the configure-storage project, and then deploy the MariaDB database from the mariadb.yaml resource file. The persistent volume claim (PVC) resource in that file requests a volume from the io1-50 storage class.

Use the oc new-project command to create the configure-storage project.

$ oc new-project configure-storage
Now using project "configure-storage" on server "https://api.do120-cluster.jf96.p1.openshiftapps.com:6443".
...output omitted...

Download the mariadb.yaml resource file at https://raw.githubusercontent.com/RedHatTraining/DO12X-apps/main/ROSA/configure-storage/mariadb.yaml.

Review the mariadb.yaml file. You do not have to change its contents. The file declares the mariadb PVC resource that uses the io1-50 storage class, and requests 4 GiB of space. The resulting volume, named mariadb-data, is mounted in the /var/lib/mysql/data directory inside the container.

---
apiVersion: v1
kind: List
metadata: {}
items:
  - apiVersion: v1
    kind: PersistentVolumeClaim
    metadata:
      labels:
        app: mariadb
      name: mariadb
    spec:
      storageClassName: io1-50
      accessModes:
        - ReadWriteOnce
      resources:
        requests:
          storage: 4Gi
...output omitted...
        spec:
          volumes:
            - name: mariadb-data
              persistentVolumeClaim:
                claimName: mariadb
          containers:
            - name: mariadb
              image: registry.redhat.io/rhel9/mariadb-105
              volumeMounts:
                - mountPath: /var/lib/mysql/data
                  name: mariadb-data
              ports:
                - containerPort: 3306
...output omitted...

Use the oc apply command to deploy the MariaDB server.

$ oc apply -f mariadb.yaml
persistentvolumeclaim/mariadb created
secret/mariadb created
deployment.apps/mariadb created
service/mariadb created

Verify that OpenShift provisions an EBS volume for the MariaDB workload.
1. Verify that OpenShift binds the mariadb PVC to a persistent volume. You might have to rerun the command several times for the command to report a Bound status.
```
$ oc get pvc
NAME      STATUS   VOLUME                                     CAPACITY   ...
mariadb   Bound    pvc-f368c5d5-1a6a-4b13-8a39-163987e6d5d9   4Gi        ...
```
  The volume name is different on your system.
2. Use the aws ec2 describe-volumes command to verify that an io1 Amazon EBS volume exists for the mariadb PVC. In the EBS volumes for OpenShift, the kubernetes.io/created-for/pvc/name tag is set to the name of the PVC. The --filter option filters the EBS volumes by that tag. The --query option limits the output to the volume type. The command output confirms that the type of the EBS volume for the mariadb PVC is io1.
```
$ aws ec2 describe-volumes \
  --filters "Name=tag:kubernetes.io/created-for/pvc/name,Values=mariadb" \
  --query "Volumes[0].VolumeType"
"io1"
```
3. Retrieve the name of the pod that runs the MariaDB server.
```
$ oc get pods
NAME                     READY   STATUS    RESTARTS   AGE
mariadb-7cd894c6-vhqpw   1/1     Running   0          30m
```
  The pod name is different on your system.
4. Use the df command inside the container to verify that the /var/lib/mysql/data directory uses the 4 GiB volume. In the following command, replace the name of the pod by the name that you retrieved in the preceding step. The file system is smaller than 4 GiB, to account for the file system overhead.
```
$ oc rsh mariadb-7cd894c6-vhqpw df -h /var/lib/mysql/data
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme1n1    3.9G  119M  3.8G   4% /var/lib/mysql/data
```
5. Clean up your work by deleting the configure-storage project.
```
$ oc delete project configure-storage
project.project.openshift.io "configure-storage" deleted
```
6. Clean up the storage class.
```
$ oc delete sc io1-50
storageclass.storage.k8s.io "io1-50" deleted
```
  Do not delete your ROSA cluster, because later exercises use it.

Revision: do120-4.12-b978842

Introduction to Red Hat OpenShift Service on AWS (ROSA)

Guided Exercise: Configure Additional Storage Classes