PLEASE NOTE: This document applies to v0.7 version and not to the latest stable release v1.9
Block storage allows you to mount storage to a single pod. This example shows how to build a simple, multi-tier web application on Kubernetes using persistent volumes enabled by Rook.
This guide assumes you have created a Rook cluster as explained in the main Quickstart guide.
Before Rook can start provisioning storage, a StorageClass and its storage pool need to be created. This is needed for Kubernetes to interoperate with Rook for provisioning persistent volumes. For more options on pools, see the documentation on creating storage pools.
Save this storage class definition as
apiVersion: rook.io/v1alpha1 kind: Pool metadata: name: replicapool namespace: rook spec: replicated: size: 3 --- apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: rook-block provisioner: rook.io/block parameters: pool: replicapool
Create the storage class.
kubectl create -f rook-storageclass.yaml
Consume the storage
We create a sample app to consume the block storage provisioned by Rook with the classic wordpress and mysql apps. Both of these apps will make use of block volumes provisioned by Rook.
Start mysql and wordpress from the
kubectl create -f mysql.yaml kubectl create -f wordpress.yaml
Both of these apps create a block volume and mount it to their respective pod. You can see the Kubernetes volume claims by running the following:
$ kubectl get pvc NAME STATUS VOLUME CAPACITY ACCESSMODES AGE mysql-pv-claim Bound pvc-95402dbc-efc0-11e6-bc9a-0cc47a3459ee 20Gi RWO 1m wp-pv-claim Bound pvc-39e43169-efc1-11e6-bc9a-0cc47a3459ee 20Gi RWO 1m
Once the wordpress and mysql pods are in the
Running state, get the cluster IP of the wordpress app and enter it in your brower:
$ kubectl get svc wordpress NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE wordpress 10.3.0.155 <pending> 80:30841/TCP 2m
You should see the wordpress app running.
NOTE: When running in a vagrant environment, there will be no external IP address to reach wordpress with. You will only be able to reach wordpress via the
CLUSTER-IP from inside the Kubernetes cluster.
To clean up all the artifacts created by the block demo:
kubectl delete -f wordpress.yaml kubectl delete -f mysql.yaml kubectl delete -n rook pool replicapool kubectl delete storageclass rook-block