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This tutorial will show you how to use Stash to backup and restore a volume in Azure Kubernetes Service. Here, we are going to backup the
/source/data folder of a busybox pod into Azure Blob Storage. Then, we are going to show how to recover this data into a
PersistentVolumeClaim(PVC). We are going to also re-deploy deployment using this recovered volume.
At first, you need to have a AKS cluster. If you don’t already have a cluster, create one from here.
Install Stash in your cluster following the steps here.
You should be familiar with the following Stash concepts:
You will need a Azure Blob Storage to store the backup snapshots.
To keep things isolated, we are going to use a separate namespace called
demo throughout this tutorial.
$ kubectl create ns demo namespace/demo created
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="$(curl -fsSL https://github.com/stashed/stash-data/raw/master/LICENSE)" \ --from-literal=README.md="$(curl -fsSL https://github.com/stashed/stash-data/raw/master/README.md)" configmap/stash-sample-data created
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 https://github.com/stashed/docs/raw/v2021.06.23/docs/examples/platforms/aks/deployment.yaml deployment.apps/stash-demo created
Now, wait for deployment’s pod to go in
$ kubectl get pod -n demo -l app=stash-demo NAME READY STATUS RESTARTS AGE stash-demo-7584fd7748-nl5n8 1/1 Running 0 3m
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-7584fd7748-nl5n8 -- ls -R /source/data /source/data: LICENSE README.md
Now, we are ready to backup
/source/data directory into Azure Blob Container.
At first, we need to create a storage secret that hold the credentials for the backend. To configure this backend, the following secret keys are needed:
Create the storage secret as below,
$ echo -n 'changeit' >RESTIC_PASSWORD $ echo -n '<your-azure-storage-account-name>' > AZURE_ACCOUNT_NAME $ echo -n '<your-azure-storage-account-key>' > AZURE_ACCOUNT_KEY $ kubectl create secret generic -n demo azure-secret \ --from-file=./RESTIC_PASSWORD \ --from-file=./AZURE_ACCOUNT_NAME \ --from-file=./AZURE_ACCOUNT_KEY secret/azure-secret created
Verify that the secret has been created successfully,
$ kubectl get secret -n demo azure-secret -o yaml
apiVersion: v1 data: AZURE_ACCOUNT_KEY: dXNlIHlvdXIgb3duIGNyZWRlbnRpYWxz # <base64 encoded AZURE_ACCOUNT_KEY> AZURE_ACCOUNT_NAME: dXNlIHlvdXIgb3duIGNyZWRlbnRpYWxz # <base64 encoded AZURE_ACCOUNT_NAME> RESTIC_PASSWORD: Y2hhbmdlaXQ= kind: Secret metadata: creationTimestamp: 2018-11-12T07:09:36Z name: azure-secret namespace: demo resourceVersion: "15708" selfLink: /api/v1/namespaces/demo/secrets/azure-secret uid: ea0b4275-e649-11e8-b68c-a62bf720de95 type: Opaque
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 Azure blob container specified in
azure.container field and start taking periodic backup of
$ kubectl apply -f https://github.com/stashed/docs/raw/v2021.06.23/docs/examples/platforms/aks/restic.yaml restic.stash.appscode.com/azure-restic created
Below, the YAML for Restic crd we have created above,
apiVersion: stash.appscode.com/v1alpha1 kind: Restic metadata: name: azure-restic namespace: demo spec: selector: matchLabels: app: stash-demo fileGroups: - path: /source/data retentionPolicyName: 'keep-last-5' backend: azure: container: stashqa prefix: demo storageSecretName: azure-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 sidecar has been injected successfully,
$ kubectl get pod -n demo -l app=stash-demo NAME READY STATUS RESTARTS AGE stash-demo-6b8c94cdd7-8jhtn 2/2 Running 1 1h
Look at the pod. It now has 2 containers. If you view the resource definition of this pod, you will see there is a container named
stash which running
Stash will create a
Repository crd with name
deployment.stash-demo for the respective repository in Azure 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 8 13s 8m
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 are created successfully by,
$ kubectl get snapshots -n demo -l repository=deployment.stash-demo NAME AGE deployment.stash-demo-52ee5eaa 4m36s deployment.stash-demo-9a3c5d10 3m36s deployment.stash-demo-39df477a 2m36s deployment.stash-demo-e315dfb4 96s deployment.stash-demo-59633ea3 36s
Here, we can see 5 last successful backup Snapshot taken by Stash in
If you navigate to
<bucket name>/demo/deployment/stash-demo directory in your Azure storage bucket. You will see, a repository has been created there.
To view the snapshot files, navigate to
snapshots directory of the repository,
Stash keeps all backup data encrypted. So, snapshot files in the bucket will not contain any meaningful data until they are decrypted.
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
stash-demo deployment and
$ kubectl delete deployment -n demo stash-demo deployment.extensions "stash-demo" deleted $ kubectl delete restic -n demo azure-restic restic.stash.appscode.com "azure-restic" deleted $ kubectl delete configmap -n demo stash-sample-data configmap "stash-sample-data" deleted
In order to perform recovery, we need
deployment.stah-demo and backend secret
azure-secret to exist.
In case of cluster disaster, you might lose
Repositorycrd and backend secret. In this scenario, you have to create the secret again and
Repositorycrd manually. Follow the guide to understand
Repositorycrd structure from here.
Let’s create a
PersistentVolumeClaim where our recovered data will be stored.
$ kubectl apply -f https://github.com/stashed/docs/raw/v2021.06.23/docs/examples/platforms/aks/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: default accessModes: - ReadWriteOnce resources: requests: storage: 50Mi
Check that if cluster has provisioned the requested claim,
$ kubectl get pvc -n demo -l app=stash-demo NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE stash-recovered Bound pvc-f6bddbf6-e66a-11e8-b68c-a62bf720de95 1Gi RWO default 1m
Look at the
stash-recovered PVC is bounded to volume
Now, we have to create a
Recovery crd to recover backed up data into this PVC.
$ kubectl apply -f https://github.com/stashed/docs/raw/v2021.06.23/docs/examples/platforms/aks/recovery.yaml recovery.stash.appscode.com/azure-recovery created
Below, the YAML for
Recovery crd we have created above.
apiVersion: stash.appscode.com/v1alpha1 kind: Recovery metadata: name: azure-recovery namespace: demo spec: repository: name: deployment.stash-demo namespace: demo paths: - /source/data recoveredVolumes: - mountPath: /source/data persistentVolumeClaim: claimName: stash-recovered
Recovery job completes its task. To verify that recovery has completed successfully run,
$ kubectl get recovery -n demo azure-recovery NAME REPOSITORYNAMESPACE REPOSITORYNAME SNAPSHOT PHASE AGE azure-recovery demo deployment.stash-demo Succeeded 3m
Succeeded indicate 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 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 azure-recovery -o yaml
We have successfully restored backup 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
Below, the YAML for
stash-demo deployment with
stash-recovered PVC as
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 https://github.com/stashed/docs/raw/v2021.06.23/docs/examples/platforms/aks/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 data are present in
Get the pod of new deployment,
$ kubectl get pod -n demo -l app=stash-demo NAME READY STATUS RESTARTS AGE stash-demo-69994758c9-v7ntg 1/1 Running 0 3m
Run following command to view data of
/source/data directory of this pod,
$ kubectl exec -n demo stash-demo-69994758c9-v7ntg -- 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.
To cleanup the resources created by this tutorial, run following commands:
$ kubectl delete recovery -n demo azure-recovery $ kubectl delete secret -n demo azure-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