Provision an application using LocalPV-hostpath

Abstract

This article provides the instructions on how to provision an application(say Percona-MySQL) using OpenEBS Local PV-hostpath. The default hostpath is configured as /var/openebs/local.

Prerequisites

• Kubernetes 1.12 or higher is required to use OpenEBS Local PV.
• OpenEBS version 1.0.0 or higher.

Step-by-Step

 The following is the sample deployment configuration of Percona application which is going to consume OpenEBS Local PV-hostpath.

STEP 1

For utilizing OpenEBS Local PV based on hostpath, use default StorageClass name as openebs-hostpath in the PVC spec of the Percona deployment.

---
apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: percona
  labels:
    name: percona
spec:
  replicas: 1
  selector: 
    matchLabels:
      name: percona 
  template: 
    metadata:
      labels: 
        name: percona
    spec:
      securityContext:
        fsGroup: 999
      tolerations:
      - key: "ak"
        value: "av"
        operator: "Equal"
        effect: "NoSchedule"
      containers:
        - resources:
            limits:
              cpu: 0.5
          name: percona
          image: percona
          args:
            - "--ignore-db-dir"
            - "lost+found"
          env:
            - name: MYSQL_ROOT_PASSWORD
              value: k8sDem0
          ports:
            - containerPort: 3306
              name: percona
          volumeMounts:
            - mountPath: /var/lib/mysql
              name: demo-vol1
      volumes:
        - name: demo-vol1
          persistentVolumeClaim:
            claimName: demo-vol1-claim
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: demo-vol1-claim
spec:
  storageClassName: openebs-hostpath
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 5G
---
apiVersion: v1
kind: Service
metadata:
  name: percona-mysql
  labels:
    name: percona-mysql
spec:
  ports:
    - port: 3306
      targetPort: 3306
  selector:
      name: percona

STEP 2

Deploy the application using the following command. In this example, the above configuration YAML spec is saved as demo-percona-mysql-pvc.yaml

kubectl apply -f demo-percona-mysql-pvc.yaml

Verify application status

The Percona application will be running on the OpenEBS local PV on hostpath. Verify if the application is running using the following command.

kubectl get pod -n <namespace>

The output will be similar to the following.

NAME                     READY STATUS   RESTARTS AGE 
percona-7b64956695-hs7tv 1/1   Running  0        21s

Verify PVC & PV status

Verify PVC status using the following command.

kubectl get pvc -n <namespace>

NAME            STATUS VOLUME                                   CAPACITY ACCESS MODES STORAGECLASS     AGE 
demo-vol1-claim Bound  pvc-2e4b123e-88ff-11e9-bc28-42010a8001ff 5G       RWO          openebs-hostpath 28s

 Verify PV status using the following command.

kubectl get pv

The output will be similar to the following.

NAME                                     CAPACITY ACCESS MODES  RECLAIM POLICY  STATUS CLAIM STORAGECLASS                             REASON    AGE 
pvc-2e4b123e-88ff-11e9-bc28-42010a8001ff 5G       RWO           Delete          Bound        default/demo-vol1-claim openebs-hostpath           22s