OpenEBS installation on GKE cluster using Rancher UI – MayaData Help Center

Note: The version of OpenEBS used is v1.15 and that of Rancher is v2.3.3 for this article.

STEP 1

Create a cluster on GKE using Rancher UI.

STEP 2

Click on "Global --> Cluster_Name --> Default".

STEP 3

After performing STEP 2, you will be redirected to the dashboard as shown in the image below.

Now, click on Apps --> Launch.

STEP 4

You will be redirected to the catalog page where you need to type "openebs" in search bar present at the top right corner in the same page. Click on openebs-logo as shown in the image below.

STEP 5

Performing STEP 4 will redirect you to Catolog : openebs Dashboard. The default namespace would be openebs. Click on Launch, present at the bottom of the dashboard as shown in the image below.

STEP 6

After STEP 5, openebs files and libraries will start getting installed on your cluster as you can see in the image below.

STEP 7

Go to "Global" view and click on the cluster on which you have installed openebs. You will be redirected to the cluster dashboard where you find "Launch Kubectl" option.

STEP 8

Click on Launch Kubectl. A shell will be opened as a result where you can execute the following command to verify the OpenEBS installation:

$ kubectl get ns

$ kubectl get pods -n openebs

Output:

STEP 9

Creating and Attaching Disks

Next, you need to create disk and attach them to the desired VMs. This can be done from the GCP console.

In order to get the detailed steps to create and attach disks in GCP, click the corresponding link:

1. Creation of disk

2. Attaching the disk

Provisioning OpenEBS volumes

Next, you have to provision OpenEBS volumes (cStor/Jiva/LocalPV). Going through the following links can help you decide as to which will be best suited for your scenario.

Click here to know about cStor.

Click here to know about Jiva.

Click here to know about LocalPV.

First, Create a cStorPool

For creation of a cStorPool you will need to specify the blockdevices, to view the disks attached execute the following command in rancher UI Shell:

kubectl get blockdevice -n <openebs_namespace>

The output looks something like this:

NAME                                         NODEN              SIZE         CLAIMSTATE  STATUS  AGE
blockdevice-66a74896b61c60dcdaf7c7a76fde0ebb pool-152c1305-x7s8 42949672960  Unclaimed   Active  2m 
blockdevice-b34b3f97840872da9aa0bac1edc9578a pool-c36a00d4-549p 42949672960  Unclaimed   Active  2m
blockdevice-ce41f8f5fa22acb79ec56292441dc207 pool-25b9dd3a-kgq5 42949672960  Unclaimed   Active  2m

Now, copy the below snippet with your blockdevices specified in a file, say cstor-pool-config.yaml

apiVersion: openebs.io/v1alpha1
kind: StoragePoolClaim
metadata:
  name: cstor-disk-pool
  annotations:
    cas.openebs.io/config: |
      - name: PoolResourceRequests
        value: |-
            memory: 2Gi
      - name: PoolResourceLimits
        value: |-
            memory: 4Gi
spec:
  name: cstor-disk-pool
  type: disk
  poolSpec:
    poolType: striped
  blockDevices:
    blockDeviceList:
    ## Replace the following with actual blockDevice CRs from your cluster using "kubectl get bd -n openebs" 
    - blockdevice-66a74896b61c60dcdaf7c7a76fde0ebb
    - blockdevice-b34b3f97840872da9aa0bac1edc9578a
    - blockdevice-ce41f8f5fa22acb79ec56292441dc207
---

Now, Go to <Cluster_name> --> Default -->Resources --> Workloads. Now click on Import Yaml present at the top right corner and import the file, cstor-pool-config.yaml , created above.
To verify execute the following command in Rancher UI shell:

kubectl get spc

The output should have a cStor-pool created:

NAME              AGE
cstor-disk-pool   1m

Next, You have to create a StorageClass.
Copy the yaml given below in a file,say cstor-sc.yaml.

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: openebs-sc-statefulset
  annotations:
    openebs.io/cas-type: cstor
    cas.openebs.io/config: |
      - name: StoragePoolClaim
        value: "cstor-disk-pool"
      - name: ReplicaCount
        value: "3"
      - name: ReplicaAntiAffinityTopoKey
        value: failure-domain.beta.kubernetes.io/zone    
provisioner: openebs.io/provisioner-iscsi

Now click on Import Yaml present at the top right corner and import the file, cstor-sc.yaml, created above.

To verify execute the following command in Rancher UI shell:

kubectl get sc

The output must contain the Storage Class name specified in the yaml file.

NAME                     PROVISIONER                         AGE
openebs-sc-statefulset   openebs.io/provisioner-iscsi        1m

Next, you need a PVC spec or volumeClaimTemplate to use the StorageClass that is pointing to a pool with real disks. The PVC is included in the application spec for the example given in STEP 10. It is mentioned here for a clearer understanding.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: cstor-pvc-mysql-large
spec:
  storageClassName: openebs-sc-statefulset
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 500Gi

The below spec represents the YAML spec for jiva, it has already been included in application spec provided in STEP 10. It is mentioned here for a clearer understanding.

    kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: demo-vol1-claim
spec:
  storageClassName: openebs-jiva-default
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 4G

You can also provision it with Local or Cloud Disks to know more click here.

LocalPVs are provisioned dynamically by OpenEBS LocalPV provisioner. LocalPV with default StorageClass can be provisioned with storage-type as device or hostpath. LocalPV gets provisioned dynamically on the node after the application is provisioned. This is ensured by adding volumeBindingMode: WaitForFirstConsumer in the yaml file

As the LocalPV gets provisioned on the node where the application is present, to have multi-zone cluster ensure the application get replicated on the desired nodes.
You can refer the following links to view the yaml file for provisioning LocalPV

STEP 10

Provisioning an application.

Now, things are all set to deploy an application and get started.

You can refer to the below sample articles for provisioning an application.

1. Sample application for cStor.

2. Sample application for Jiva.

3. Sample application for Local PV.

STEP 11

Backing up Application

It is extremely important to have a data backup and restore mechanism so that the service continues flawlessly in every situation.

Backup and Restore for cStor can be done using DMaaS, a solution for data agility and data motion in Kubernetes platform. DMaaS being application aware ensures that the state of application remains consistent before and after migration, also the time taken to restore the operations back to normal mode is quite optimised.
DMaaS is an offering from MayaData that works with both Director Online as well as OnPrem. To know more about configuring DMaaS with your cluster click here.

For applications provisioned using LocalPV and Jiva volume, restore and backup can be done using Velero. Velero provides tools to backup and restore Kubernetes cluster resources and persistent volume. Velero gives you tools to back up and restore your Kubernetes cluster resources and persistent volumes. Using Velero you can:

Take backups of your cluster and restore in case of loss.
Migrate cluster resources to other clusters.
Replicate your production cluster to development and testing clusters.

You can run Velero in clusters on a cloud provider or on-premises.
To know the steps to create and manage backups of jiva volume using Velero Click Here.
To know the steps to create and manage backups of LoacalPV using Velero Click Here.

STEP 12

Monitoring of stateful applications and OpenEBS volumes

Once the entire thing is set up, volumes are provisioned, the application is deployed it is necessary to monitor these components continuously. Director provides easy and efficient monitoring. To know about how to monitor, different monitoring views click here.

OpenEBS volumes can be deployed on various other Kubernetes Platforms as well, to know about it Click Here.

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