Velero for Kubernetes: Backup & Restore Stateful Workloads with AWS EBS Snapshots

This article is part of a series of blog posts on using Velero for Kubernetes backup, restore, migration & disaster recovery.

All articles in this series explore Velero in the context of AWS Elastic Kubernetes Service (EKS).

Stay tuned as we publish more articles in the coming weeks & months. Here’s a sneak preview of what’s to come:

  1. An Introduction to Velero for Kubernetes Backup & Restore
  2. Velero for Kubernetes Backup: Install & Configure
  3. Backup & Restore Stateless Workloads with Velero for Kubernetes
  4. Velero for Kubernetes: Backup & Restore Stateful Workloads with AWS EBS Snapshots
  5. Velero for Kubernetes: Backup & Restore Stateful Workloads with Restic for Velero
  6. Monitoring Velero Kubernetes Backups & Automated Alerting for Backup Failures

Introduction

In the earlier post in this series, we explored how to backup & restore a stateless Nginx workload.

In this article, we will use Velero to backup & restore a stateful WordPress workload.

Install WordPress

First, let’s install WordPress as a Helm chart from Bitnami:

helm repo add bitnami https://charts.bitnami.com/bitnami

helm install wordpress bitnami/wordpress \
    --namespace wordpress --create-namespace

Wait for it to spin up:

> kubectl get namespaces

NAME              STATUS   AGE
default           Active   10d
kube-node-lease   Active   10d
kube-public       Active   10d
kube-system       Active   10d
velero            Active   22h
wordpress         Active   18h
> kubectl get all --namespace wordpress

NAME                             READY   STATUS    RESTARTS   AGE
pod/wordpress-7ff458b78c-bhmpf   1/1     Running   0          18h
pod/wordpress-mariadb-0          1/1     Running   0          18h

NAME                        TYPE           CLUSTER-IP       EXTERNAL-IP                                                               PORT(S)                      AGE
service/wordpress           LoadBalancer   10.100.52.66     abcf13174045d4fde962cbf9b4be5d06-373553114.ap-south-1.elb.amazonaws.com   80:31079/TCP,443:32376/TCP   18h
service/wordpress-mariadb   ClusterIP      10.100.196.201   <none>                                                                    3306/TCP                     18h

NAME                        READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/wordpress   1/1     1            1           18h

NAME                                   DESIRED   CURRENT   READY   AGE
replicaset.apps/wordpress-7ff458b78c   1         1         1       18h

NAME                                 READY   AGE
statefulset.apps/wordpress-mariadb   1/1     18h

Add Some State

Since this is supposed to be a stateful app, let’s add some state to the app.

Go to LOAD_BALANCER_URL/admin, login with the username user & add a blog post. Get the user’s password by running:

kubectl get secret wordpress \
    --namespace wordpress \
    -o jsonpath="{.data.wordpress-password}" \
    | base64 --decode

Backup WordPress

Now backup the entire workload:

velero backup create wordpress \
    --include-namespaces wordpress
> velero backup describe wordpress

Name:         wordpress
Namespace:    velero
Labels:       velero.io/storage-location=default
Annotations:  velero.io/source-cluster-k8s-gitversion=v1.21.5-eks-bc4871b
              velero.io/source-cluster-k8s-major-version=1
              velero.io/source-cluster-k8s-minor-version=21+

Phase:  Completed

Errors:    0
Warnings:  0

Namespaces:
  Included:  wordpress
  Excluded:  <none>

Resources:
  Included:        *
  Excluded:        <none>
  Cluster-scoped:  auto

Label selector:  <none>

Storage Location:  default

Velero-Native Snapshot PVs:  auto

TTL:  720h0m0s

Hooks:  <none>

Backup Format Version:  1.1.0

Started:    2022-01-22 22:09:05 +0530 IST
Completed:  2022-01-22 22:09:07 +0530 IST

Expiration:  2022-02-21 22:09:05 +0530 IST

Total items to be backed up:  48
Items backed up:              48

Velero-Native Snapshots:  2 of 2 snapshots completed successfully (specify --details for more information)

Ah, it looks like our persistent volumes were backup up as EBS snapshots. Let’s take a look:

Excellent! Now let’s try deleting & recovering this workload!

Delete WordPress

Simulate a data loss by deleting WordPress:

> kubectl delete namespace wordpress

namespace "wordpress" deleted

Notice the WordPress load balancer is gone too:

Restore WordPress

Let’s try a Velero restore from our WordPress backup:

> velero restore create wordpress --from-backup wordpress

Restore request "wordpress" submitted successfully.

Run `velero restore describe wordpress` or
`velero restore logs wordpress` for more details.
> velero restore describe wordpress

Name:         wordpress
Namespace:    velero
Labels:       <none>
Annotations:  <none>

Phase:                       Completed
Total items to be restored:  26
Items restored:              26

Started:    2022-01-23 17:12:08 +0530 IST
Completed:  2022-01-23 17:12:10 +0530 IST

Backup:  wordpress

Namespaces:
  Included:  all namespaces found in the backup
  Excluded:  <none>

Resources:
  Included:        *
  Excluded:        nodes, events, events.events.k8s.io, backups.velero.io, restores.velero.io, resticrepositories.velero.io
  Cluster-scoped:  auto

Namespace mappings:  <none>

Label selector:  <none>

Restore PVs:  auto

Preserve Service NodePorts:  auto

And now, for the moment of truth: did we lose our data forever?

Find the new WordPress load balancer URL:

> kubectl get all --namespace wordpress

NAME                             READY   STATUS    RESTARTS   AGE
pod/wordpress-7ff458b78c-bhmpf   1/1     Running   0          3m55s
pod/wordpress-mariadb-0          1/1     Running   0          3m55s

NAME                        TYPE           CLUSTER-IP       EXTERNAL-IP                                                               PORT(S)                      AGE
service/wordpress           LoadBalancer   10.100.3.69      a391b6489f3b04124a54350b4aa94ac0-450229137.ap-south-1.elb.amazonaws.com   80:30158/TCP,443:30719/TCP   3m55s
service/wordpress-mariadb   ClusterIP      10.100.133.158   <none>                                                                    3306/TCP                     3m55s

NAME                        READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/wordpress   1/1     1            1           3m55s

NAME                                   DESIRED   CURRENT   READY   AGE
replicaset.apps/wordpress-7ff458b78c   1         1         1       3m55s

NAME                                 READY   AGE
statefulset.apps/wordpress-mariadb   1/1     3m55s

If you now visit the WordPress URL, you can see all the blog posts you added to your WordPress instance before it was deleted!

Conclusion

We have successfully backed up & restored a stateful Kubernetes workload using AWS EBS snapshots!

About the Author ✍🏻

Harish KM is a Principal DevOps Engineer at QloudX & a top-ranked APN Ambassador. 👨🏻‍💻

With over a decade of industry experience as everything from a full-stack engineer to a cloud architect, Harish has built many world-class solutions for clients around the world! 👷🏻‍♂️

With over 20 certifications in cloud (AWS, Azure, GCP), containers (Kubernetes, Docker) & DevOps (Terraform, Ansible, Jenkins), Harish is an expert in a multitude of technologies. 📚

These days, his focus is on the fascinating world of DevOps & how it can transform the way we do things! 🚀

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