README.md

Exercise 2 - Installing OpenEBS

In this exercise, we will learn how to deploy and validate OpenEBS on a functional Kubernetes cluster.

Setting up OpenEBS and new Storage Classes

1. Download the latest OpenEBS Operator files using the following commands:

   git clone https://github.com/openebs/openebs.git
   cd openebs/k8s
   

2. By default, OpenEBS launches OpenEBS Volumes with three replicas. To set one replica, as is the case with a single-node Kubernetes cluster, in the openebs-operator.yaml file, specify the environment variable DEFAULT_REPLICA_COUNT=1 or edit the operator file directly.

3. Optional: By default, OpenEBS uses /var/openebs directory on every available node to create replica files. If you like to change the default or create a new StoragePool resource, you can edit openebs-config.yaml file and set a custom path.

4. Apply the configuration changes:

   kubectl apply -f openebs-operator.yaml
   kubectl apply -f openebs-config.yaml
   

5. Add the OpenEBS storage classes that can then be used by developers and applications:

   kubectl apply -f openebs-storageclasses.yaml
   

6. Validate OpenEBS deployment

   $ kubectl get pods --namespace openebs
   NAME                                           READY     STATUS    RESTARTS   AGE
   maya-apiserver-6cfd67f8-2nlhd                  1/1       Running   0          21s
   openebs-provisioner-6797d44769-dxk82           1/1       Running   0          21s
   openebs-snapshot-controller-565d8f576d-pj5f9   2/2       Running   0          21s
   

   Confirm that all the three OpenEBS pods (maya-apiserver, openebs-provisioner and openebs-snapshot-controller) are in Running state.

   To use OpenEBS as persistent storage for your stateful workloads, we will need to set the storageclass in the Persistent Volume Claim (PVC) of your application to one of the OpenEBS storage class, therefore you need to know the storageclass name.

7. Get the list of storage classes using the following command. Choose a storageclass that best suits your application.

   $ kubectl get sc
   NAME                 PROVISIONER                                                AGE
   openebs-cassandra    openebs.io/provisioner-iscsi                               2m
   openebs-es-data-sc   openebs.io/provisioner-iscsi                               2m
   openebs-jupyter      openebs.io/provisioner-iscsi                               2m
   openebs-kafka        openebs.io/provisioner-iscsi                               2m
   openebs-mongodb      openebs.io/provisioner-iscsi                               2m
   openebs-percona      openebs.io/provisioner-iscsi                               2m
   openebs-redis        openebs.io/provisioner-iscsi                               2m
   openebs-standalone   openebs.io/provisioner-iscsi                               2m
   openebs-standard     openebs.io/provisioner-iscsi                               2m
   openebs-zk           openebs.io/provisioner-iscsi                               2m
   snapshot-promoter    volumesnapshot.external-storage.k8s.io/snapshot-promoter   2m
   

8. Optional: To create your own storage class, create a YAML file (example: mystorageclass.yaml) similar to below, customize parameters, save and apply using `kubectl apply -f mystorageclass.yaml' command:

   # Define a storage classes supported by OpenEBS
   
   apiVersion: storage.k8s.io/v1
   kind: StorageClass
   metadata:
      name: openebs-mystorageclass
   provisioner: openebs.io/provisioner-iscsi
   parameters:
     openebs.io/storage-pool: "default"
     openebs.io/jiva-replica-count: "4"
     openebs.io/volume-monitor: "true"
     openebs.io/capacity: 5G
   

9. To see the storage class definition such as storage pool, replica count and capacity run the comment below:

   $ kubectl describe sc openebs-standard
   Name:            openebs-standard
   IsDefaultClass:  No
   Annotations:     kubectl.kubernetes.io/last-applied-configuration={"apiVersion":"storage.k8s.io/v1","kind":"StorageClass","metadata":{"annotations":{},"name":"openebs-standard","namespace":""},"parameters":{"openebs.io/capacity":"5G","openebs.io/jiva-replica-count":"3","openebs.io/storage-pool":"default","openebs.io/volume-monitor":"true"},"provisioner":"openebs.io/provisioner-iscsi"}
   
   Provisioner:           openebs.io/provisioner-iscsi
   Parameters:            openebs.io/capacity=5G,openebs.io/jiva-replica-count=3,openebs.io/storage-pool=default,openebs.io/volume-monitor=true
   AllowVolumeExpansion:  <unset>
   MountOptions:          <none>
   ReclaimPolicy:         Delete
   VolumeBindingMode:     Immediate
   Events:                <none>
   

Now you have your OpenEBS deployment up and running.

Continue to Exercise 3 - Deploying stateful workload on OpenEBS