This topic describes how to use Velero to back up and restore a stateless application using the label selector feature with Velero.

Overview

To test Velero back up and restore, use the stateless Guestbook application. This example demonstrates Velero back up and restore with label selectors, so the stateless Guestbook app is deployed using labels.

Prerequisites

Install and configure MinIO, Velero, and restic.

Download the Guestbook app YAML files to a local known directory:

  • redis-leader-deployment.yaml
  • redis-leader-service.yaml
  • redis-follower-deployment.yaml
  • redis-follower-service.yaml
  • frontend-deployment.yaml
  • frontend-service.yaml

Deploy Guestbook App

Create Guestbook namespace:

kubectl create ns guestbook
namespace/guestbook created

Deploy the Guestbook app:

kubectl apply -f . -n guestbook

deployment.apps/frontend created
service/frontend created
deployment.apps/redis-leader created
service/redis-leader created
deployment.apps/redis-follower created
service/redis-follower created
root@PKS-client-VM-WA:/DATA/K8s-Apps

Verify:

kubectl get all  -n guestbook --show-labels

NAME                                READY   STATUS    RESTARTS   AGE   LABELS
pod/frontend-6cb7f8bd65-57lmk       1/1     Running   0          18m   app=guestbook,pod-template-hash=6cb7f8bd65,tier=frontend
pod/frontend-6cb7f8bd65-92j8j       1/1     Running   0          18m   app=guestbook,pod-template-hash=6cb7f8bd65,tier=frontend
pod/frontend-6cb7f8bd65-mvrqg       1/1     Running   0          18m   app=guestbook,pod-template-hash=6cb7f8bd65,tier=frontend
pod/redis-leader-7b8487bf68-gmkgp   1/1     Running   0          18m   app=redis,pod-template-hash=7b8487bf68,role=leader,tier=backend
pod/redis-follower-5bdcfd74c7-7jjg6 1/1     Running   0          18m   app=redis,pod-template-hash=5bdcfd74c7,role=follower,tier=backend
pod/redis-follower-5bdcfd74c7-mbdcr 1/1     Running   0          18m   app=redis,pod-template-hash=5bdcfd74c7,role=follower,tier=backend

NAME                   TYPE           CLUSTER-IP      EXTERNAL-IP    PORT(S)        AGE   LABELS
service/frontend       LoadBalancer   10.100.200.64   10.199.41.15   80:30698/TCP   18m   app=guestbook,tier=frontend
service/redis-leader   ClusterIP      10.100.200.98   <none>         6379/TCP       18m   app=redis,role=leader,tier=backend
service/redis-follower    ClusterIP      10.100.200.47   <none>         6379/TCP       18m   app=redis,role=follower,tier=backend

NAME                           READY   UP-TO-DATE   AVAILABLE   AGE   LABELS
deployment.apps/frontend       3/3     3            3           18m   <none>
deployment.apps/redis-leader   1/1     1            1           18m   <none>
deployment.apps/redis-follower    2/2     2            2           18m   <none>

NAME                                      DESIRED   CURRENT   READY   AGE   LABELS
replicaset.apps/frontend-6cb7f8bd65       3         3         3       18m   app=guestbook,pod-template-hash=6cb7f8bd65,tier=frontend
replicaset.apps/redis-leader-7b8487bf68   1         1         1       18m   app=redis,pod-template-hash=7b8487bf68,role=leader,tier=backend
replicaset.apps/redis-follower-5bdcfd74c7    2         2         2       18m   app=redis,pod-template-hash=5bdcfd74c7,role=follower,tier=backend

Access the Guestbook app at http://10.199.41.15/.

Guestbook App

Apply a Common Label to all App Objects

By default, there is no common label that encompasses all the Kubernetes objects in the namespace guestbook for the application. Here you apply a common label, application=guestbook, to these objects.

kubectl label -n guestbook pod --all  application=guestbook

kubectl label -n guestbook service --all  application=guestbook

kubectl label -n guestbook deployment --all  application=guestbook

kubectl label -n guestbook replicaset --all  application=guestbook

Verify: you should see all pods in the application with the same guestbook label:

kubectl get all -n guestbook --show-labels

Back Up the Guestbook App Using Label

When backing up an application using Velero with the label option, only one label can be specified in the --selector field. This means the label must be present on all the Kubernetes objects that belong to the application.

velero backup create guestbook-backup-label --selector application=guestbook

Backup request "guestbook-backup-label" submitted successfully.
Run `velero backup describe guestbook-backup-label` or `velero backup logs guestbook-backup-label` for more details.

Verify:

velero backup describe guestbook-backup-label --details

Expected result:

Name:         guestbook-backup-label
Namespace:    velero
Labels:       velero.io/storage-location=default
Annotations:  velero.io/source-cluster-k8s-gitversion=v1.17.8+vmware.1
              velero.io/source-cluster-k8s-major-version=1
              velero.io/source-cluster-k8s-minor-version=17

Phase:  Completed

Errors:    0
Warnings:  0

Namespaces:
  Included:  *
  Excluded:  <none>

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

Label selector:  application=guestbook

Storage Location:  default

Velero-Native Snapshot PVs:  auto

TTL:  720h0m0s

Hooks:  <none>

Backup Format Version:  1

Started:    2020-07-22 14:46:41 -0700 PDT
Completed:  2020-07-22 14:46:43 -0700 PDT

Expiration:  2020-08-21 14:46:41 -0700 PDT

Total items to be backed up:  18
Items backed up:              18

Resource List:
  apps/v1/Deployment:
    - guestbook/frontend
    - guestbook/redis-leader
    - guestbook/redis-follower
  apps/v1/ReplicaSet:
    - guestbook/frontend-6cb7f8bd65
    - guestbook/redis-leader-7b8487bf68
    - guestbook/redis-follower-5bdcfd74c7
  v1/Endpoints:
    - guestbook/frontend
    - guestbook/redis-leader
    - guestbook/redis-follower
  v1/Pod:
    - guestbook/frontend-6cb7f8bd65-57lmk
    - guestbook/frontend-6cb7f8bd65-92j8j
    - guestbook/frontend-6cb7f8bd65-mvrqg
    - guestbook/redis-leader-7b8487bf68-gmkgp
    - guestbook/redis-follower-5bdcfd74c7-7jjg6
    - guestbook/redis-follower-5bdcfd74c7-mbdcr
  v1/Service:
    - guestbook/frontend
    - guestbook/redis-leader
    - guestbook/redis-follower

Velero-Native Snapshots: <none included>

Verify the backup that was created.

velero backup get

NAME               STATUS      ERRORS   WARNINGS   CREATED                         EXPIRES   STORAGE LOCATION   SELECTOR
guestbook-backup   Completed   0        0          2020-07-21 14:45:51 -0700 PDT   29d       default            <none>

Also, check the tkgi-velero bucket on the MinIO server.

Velero writes some metadata in Kubernetes CustomResourceDefinition (CRD).

kubectl get crd

The Velero CRDs let you run certain commands, such as the following:

kubectl get backups.velero.io -n velero

NAME                     AGE
guestbook-backup         24h
guestbook-backup-label   2m16s

kubectl describe backups.velero.io guestbook-backup-label -n velero

Name:         guestbook-backup-label
Namespace:    velero
Labels:       velero.io/storage-location=default
Annotations:  velero.io/source-cluster-k8s-gitversion: v1.17.8+vmware.1
              velero.io/source-cluster-k8s-major-version: 1
              velero.io/source-cluster-k8s-minor-version: 17
API Version:  velero.io/v1
Kind:         Backup
Metadata:
  Creation Timestamp:  2020-07-22T21:46:41Z
  Generation:          5
  Resource Version:    3597347
  Self Link:           /apis/velero.io/v1/namespaces/velero/backups/guestbook-backup-label
  UID:                 0a88adde-1c1a-4988-828f-886aa14fda17
Spec:
  Hooks:
  Included Namespaces:
    *
  Label Selector:
    Match Labels:
      Application:   guestbook
  Storage Location:  default
  Ttl:               720h0m0s
Status:
  Completion Timestamp:  2020-07-22T21:46:43Z
  Expiration:            2020-08-21T21:46:41Z
  Format Version:        1.1.0
  Phase:                 Completed
  Progress:
    Items Backed Up:  18
    Total Items:      18
  Start Timestamp:    2020-07-22T21:46:41Z
  Version:            1
Events:               <none>

Restore the Guestbook App Using Label

To test the restoration of the Guestbook app, delete the namespace:

kubectl delete ns guestbook
namespace "guestbook" deleted

Restore the Guestbook app:

velero restore create --from-backup guestbook-backup-label

Restore request "guestbook-backup-label-20200722145118" submitted successfully.
Run `velero restore describe guestbook-backup-label-20200722145118` or `velero restore logs guestbook-backup-label-20200722145118` for more details.

Verify that the app is restored:

velero restore describe guestbook-backup-label-20200722145118

Name:         guestbook-backup-label-20200722145118
Namespace:    velero
Labels:       <none>
Annotations:  <none>

Phase:  Completed

Backup:  guestbook-backup-label

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

Run the following commands to verify:

velero restore get

NAME                                    BACKUP                   STATUS      ERRORS   WARNINGS   CREATED                         SELECTOR
guestbook-backup-20200721145620         guestbook-backup         Completed   0        0          2020-07-21 14:56:20 -0700 PDT   <none>
guestbook-backup-label-20200722145118   guestbook-backup-label   Completed   0        0          2020-07-22 14:51:18 -0700 PDT   <none>

kubectl get ns

NAME              STATUS   AGE
default           Active   13d
guestbook         Active   19s
kube-node-lease   Active   13d
kube-public       Active   13d
kube-system       Active   13d
pks-system        Active   13d
velero            Active   50m

kubectl get all -n guestbook --show-labels

Access the Guestbook app at http://10.199.41.14/.

Guestbook App

Conclusions

Note the following:

  • The namespace guestbook is automatically re-created.
  • The IP address for the Kubernetes service load balancer is changed from 10.199.41.10 to .14.
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