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Using Stash with Rook Storage Service

This tutorial will show you how to use Stash to backup and restore a Kubernetes volume in Rook storage service. Here, we are going to backup the /source/data folder of a busybox pod into AWS S3 compatible Rook Object Storage. Then, we are going to show how to recover this data into a PersistentVolumeClaim of Rook Block Storage. We are going to also re-deploy deployment using this recovered volume.

Before You Begin

At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikube.

To keep things isolated, we are going to use a separate namespace called demo throughout this tutorial.

$ kubectl create ns demo
namespace/demo created

Note: YAML files used in this tutorial are stored in /docs/examples/platforms/rook directory of appscode/stash repository.

Backup

In order to take backup, we need some sample data. Stash has some sample data in stash-data repository. As gitRepo volume has been deprecated, we are not going to use this repository as volume directly. Instead, we are going to create a configMap from the stash-data repository and use that ConfigMap as data source.

Let’s create a ConfigMap from these sample data,

$ kubectl create configmap -n demo stash-sample-data \
	--from-literal=LICENSE="$(curl -fsSL https://raw.githubusercontent.com/appscode/stash-data/master/LICENSE)" \
	--from-literal=README.md="$(curl -fsSL https://raw.githubusercontent.com/appscode/stash-data/master/README.md)"
configmap/stash-sample-data created

Deploy Workload:

Now, deploy the following Deployment. Here, we have mounted the ConfigMap stash-sample-data as data source volume.

Below, the YAML for the Deployment we are going to create.

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: stash-demo
  name: stash-demo
  namespace: demo
spec:
  replicas: 1
  selector:
    matchLabels:
      app: stash-demo
  template:
    metadata:
      labels:
        app: stash-demo
      name: busybox
    spec:
      containers:
      - args:
        - sleep
        - "3600"
        image: busybox
        imagePullPolicy: IfNotPresent
        name: busybox
        volumeMounts:
        - mountPath: /source/data
          name: source-data
      restartPolicy: Always
      volumes:
      - name: source-data
        configMap:
          name: stash-sample-data

Let’s create the deployment we have shown above,

$ kubectl apply -f ./docs/examples/platforms/rook/deployment.yaml
deployment.apps/stash-demo created

Now, wait for deployment’s pod to go in Running state.

$ kubectl get pod -n demo -l app=stash-demo
NAME                          READY   STATUS    RESTARTS   AGE
stash-demo-7ccd56bf5d-fm74f   1/1     Running   0          18s

You can check that the /source/data/ directory of this pod is populated with data from the stash-sample-data ConfigMap using this command,

$ kubectl exec -n demo stash-demo-7ccd56bf5d-fm74f -- ls -R /source/data
/source/data:
LICENSE
README.md

Now, we are ready to backup /source/data directory into a Rook bucket.

Create Secret:

At first, we need to create a secret for Restic crd. To configure this backend, the following secret keys are needed:

Key Description
RESTIC_PASSWORD Required. Password used to encrypt snapshots by restic
AWS_ACCESS_KEY_ID Required. Rook access key
AWS_SECRET_ACCESS_KEY Required. Rook secret key

Create the secret as below,

$ echo -n 'changeit' > RESTIC_PASSWORD
$ echo -n '<your-rook-access-key-here>' > AWS_ACCESS_KEY_ID
$ echo -n '<your-rook-secret-key-here>' > AWS_SECRET_ACCESS_KEY
$ kubectl create secret generic -n demo rook-secret \
    --from-file=./RESTIC_PASSWORD \
    --from-file=./AWS_ACCESS_KEY_ID \
    --from-file=./AWS_SECRET_ACCESS_KEY
secret/rook-secret created

Verify that the secret has been created successfully,

$ kubectl get secret -n demo rook-secret -o yaml
apiVersion: v1
data:
  AWS_ACCESS_KEY_ID: UlhSQ0oyVjRZNlpFQUlBV0UyTEc=
  AWS_SECRET_ACCESS_KEY: YWVtZG9IZ1g3UXBUSzF0VXpPZHVJcUNPb01sc1cwZlZES0RRaXM2MA==
  RESTIC_PASSWORD: Y2hhbmdlaXQ=
kind: Secret
metadata:
  creationTimestamp: 2018-12-06T07:24:58Z
  name: rook-secret
  namespace: demo
  resourceVersion: "4680"
  selfLink: /api/v1/namespaces/demo/secrets/rook-secret
  uid: 0958c36c-f928-11e8-998e-080027a2d1ee
type: Opaque

Create Restic:

Now, we are going to create Restic crd to take backup /source/data directory of stash-demo deployment. This will create a repository in the Rook bucket specified by s3.bucket field and start taking periodic backup of /source/data directory.

$ kubectl apply -f ./docs/examples/platforms/rook/restic.yaml
restic.stash.appscode.com/rook-restic created

Below, the YAML for Restic crd we have created above,

apiVersion: stash.appscode.com/v1alpha1
kind: Restic
metadata:
  name: rook-restic
  namespace: demo
spec:
  selector:
    matchLabels:
      app: stash-demo # Must match with the label of pod we want to backup.
  fileGroups:
  - path: /source/data
    retentionPolicyName: 'keep-last-5'
  backend:
    s3:
      endpoint: 'http://rook-ceph-rgw-my-store.rook-ceph.svc' # Use your own rook object storage endpoint.
      bucket: stash-backup  # Give a name of the bucket where you want to backup.
      prefix: demo  # A prefix for the directory where repository will be created.(optional).
    storageSecretName: rook-secret
  schedule: '@every 1m'
  volumeMounts:
  - mountPath: /source/data
    name: source-data
  retentionPolicies:
  - name: 'keep-last-5'
    keepLast: 5
    prune: true

If everything goes well, Stash will inject a sidecar container into the stash-demo deployment to take periodic backup. Let’s check that sidecar has been injected successfully,

$ kubectl get pod -n demo -l app=stash-demo
NAME                          READY   STATUS    RESTARTS   AGE
stash-demo-6c9cd4cf4c-bn5wm   2/2     Running   0          53s

Look at the pod. It now has 2 containers. If you view the resource definition of this pod, you will see that there is a container named stash which running backup command.

Verify Backup:

Stash will create a Repository crd with name deployment.stash-demo for the respective repository in Rook backend at first backup schedule. To verify, run the following command,

$ kubectl get repository deployment.stash-demo -n demo
NAME                    BACKUPCOUNT   LASTSUCCESSFULBACKUP   AGE
deployment.stash-demo   1             41s                    1m

Here, BACKUPCOUNT field indicates number of backup snapshot has taken in this repository.

Restic will take backup of the volume periodically with a 1-minute interval. You can verify that backup snapshots has been created successfully by,

$ kubectl get snapshots -n demo -l repository=deployment.stash-demo
NAME                             AGE
NAME                             AGE
deployment.stash-demo-2960b90e   4m3s
deployment.stash-demo-79626d95   3m3s
deployment.stash-demo-6c5eb448   2m3s
deployment.stash-demo-05761ab3   63s
deployment.stash-demo-f8937bdf   2s

Here, we can see 5 last successful backup Snapshot taken by Stash in deployment.stash-demo repository.

Recovery

Now, consider that we have lost our workload as well as data volume. We want to recover the data into a new volume and re-deploy the workload.

At first, let’s delete Restic crd, stash-demo deployment and stash-sample-data ConfigMap.

$ kubectl delete deployment -n demo stash-demo
deployment.extensions "stash-demo" deleted

$ kubectl delete restic -n demo rook-restic
restic.stash.appscode.com "rook-restic" deleted

$ kubectl delete configmap -n demo stash-sample-data
configmap "stash-sample-data" deleted

In order to perform recovery, we need Repository crd deployment.stah-demo and backend secret rook-secret to exist.

In case of cluster disaster, you might lose Repository crd and backend secret. In this scenario, you have to create the secret again and Repository crd manually. Follow the guide to understand Repository crd structure from here.

Create PVC:

We are going to recover our backed up data into a PVC. Rook Block Storage allows mounting Rook storage into pod using a PersistentVolumeClaim. At first, we need to know respective StorageClass for Rook Block Storage.

$ kubectl get storageclass
NAME                 PROVISIONER                AGE
rook-ceph-block      ceph.rook.io/block         96m
standard (default)   k8s.io/minikube-hostpath   124m

Here, rook-ceph-block storage class is responsible for provisioning the PVC from Rook Block Storage.

Let’s create a PersistentVolumeClaim with rook-ceph-block storage class where our recovered data will be stored.

$ kubectl apply -f ./docs/examples/platforms/rook/rook-pvc.yaml
persistentvolumeclaim/stash-recovered created

Below the YAML for PersistentVolumeClaim we have created above,

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: stash-recovered
  namespace: demo
  labels:
    app: stash-demo
spec:
  storageClassName: rook-ceph-block
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 50Mi

Check that if cluster has provisioned the requested claim,

$ kubectl get pvc -n demo -l app=stash-demo
kubectl get pvc -n demo -l app=stash-demo
NAME              STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS      AGE
stash-recovered   Bound    pvc-dd0739b2-f934-11e8-998e-080027a2d1ee   50Mi       RWO            rook-ceph-block   46s

Look at the STATUS filed. stash-recovered PVC is bounded to volume pvc-dd0739b2-f934-11e8-998e-080027a2d1ee.

Create Recovery:

Now, we have to create a Recovery crd to recover backed up data into this PVC.

$ kubectl apply -f ./docs/examples/platforms/rook/recovery.yaml
recovery.stash.appscode.com/rook-recovery created

Below, the YAML for Recovery crd we have created above.

apiVersion: stash.appscode.com/v1alpha1
kind: Recovery
metadata:
  name: rook-recovery
  namespace: demo
spec:
  repository:
    name: deployment.stash-demo
    namespace: demo
  paths:
  - /source/data
  recoveredVolumes:
  - mountPath: /source/data
    persistentVolumeClaim:
      claimName: stash-recovered

Wait until Recovery job completes its task. To verify that recovery has completed successfully run,

$ kubectl get recovery -n demo rook-recovery
NAME            REPOSITORYNAMESPACE   REPOSITORYNAME          SNAPSHOT   PHASE       AGE
rook-recovery   demo                  deployment.stash-demo              Succeeded   26s

Here, PHASE Succeeded indicates that our recovery has been completed successfully. Backup data has been restored in stash-recovered PVC. Now, we are ready to use this PVC to re-deploy the workload.

If you are using Kubernetes version older than v1.11.0 then run following command and check status.phase field to see whether the recovery succeeded or failed.

$ kubectl get recovery -n demo rook-recovery -o yaml

Re-deploy Workload:

We have successfully restored backed up data into stash-recovered PVC. Now, we are going to re-deploy our previous deployment stash-demo. This time, we are going to mount the stash-recovered PVC as source-data volume instead of ConfigMap stash-sample-data.

Below, the YAML for stash-demo deployment with stash-recovered PVC as source-data volume.

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: stash-demo
  name: stash-demo
  namespace: demo
spec:
  replicas: 1
  selector:
    matchLabels:
      app: stash-demo
  template:
    metadata:
      labels:
        app: stash-demo
      name: busybox
    spec:
      containers:
      - args:
        - sleep
        - "3600"
        image: busybox
        imagePullPolicy: IfNotPresent
        name: busybox
        volumeMounts:
        - mountPath: /source/data
          name: source-data
      restartPolicy: Always
      volumes:
      - name: source-data
        persistentVolumeClaim:
          claimName: stash-recovered

Let’s create the deployment,

$ kubectl apply -f ./docs/examples/platforms/rook/recovered-deployment.yaml
deployment.apps/stash-demo created

Verify Recovered Data:

We have re-deployed stash-demo deployment with recovered volume. Now, it is time to verify that the recovered data are present in /source/data directory.

Get the pod of new deployment,

$ kubectl get pod -n demo -l app=stash-demo
NAME                          READY   STATUS    RESTARTS   AGE
stash-demo-69694789df-rsrz6   1/1     Running   0          15s

Run following command to view data of /source/data directory of this pod,

$ kubectl exec -n demo stash-demo-69694789df-rsrz6 -- ls -R /source/data
source/data:
LICENSE
README.md
lost+found

/source/data/lost+found:

So, we can see that the data we had backed up from original deployment are now present in re-deployed deployment.

Cleanup

To cleanup the resources created by this tutorial, run following commands:

$ kubectl delete recovery -n demo rook-recovery
$ kubectl delete secret -n demo rook-secret
$ kubectl delete deployment -n demo stash-demo
$ kubectl delete pvc -n demo stash-recovered
$ kubectl delete repository -n demo deployment.stash-demo

$ kubectl delete ns demo
  • To uninstall Stash from your cluster, follow the instructions from here.

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