Learn Kubernetes: A Deep Dive/

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How to Perform a Rollback

How to Perform a Rollback

Learn how to perform a rollback on a Deployment.

We'll cover the following...

As previously mentioned, Kubernetes keeps old ReplicaSets as a documented revision history and an easy way to rollback. Use the following widget to execute all the commands mentioned in this lesson:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello-deploy
spec:
  replicas: 10
  selector:
    matchLabels:
      app: hello-world
  revisionHistoryLimit: 5
  progressDeadlineSeconds: 300
  minReadySeconds: 10
  strategy:
    type: RollingUpdate 
    rollingUpdate:
      maxUnavailable: 1
      maxSurge: 1
  template:
    metadata:
      labels:
        app: hello-world
    spec:
      containers:
      - name: hello-pod
        image: nigelpoulton/k8sbook:2.0
        ports:
        - containerPort: 8080
        resources:
          limits:
            memory: 128Mi
            cpu: 0.1
Playground

The following command shows the history of the Deployment with two revisions.

$ kubectl rollout history deployment hello-deploy
deployment.apps/hello-deploy
REVISION  CHANGE-CAUSE
1         <none>
2         <none>
Get the history of Deployment

Revision 1 was the initial release based on the 1.0 image. Revision 2 is the rollout that updated the Pods to run version 2.0 of the image.

The following command shows the two ReplicaSets associated with each of the revisions.

$ kubectl get rs
NAME                      DESIRED   CURRENT   READY   AGE
hello-deploy-5f84c5b7b7   10        10        10      27m
hello-deploy-54f5d46964   0         0         0       93m
Get the status of ReplicaSets

The next kubectl describe command runs against the old ReplicaSet and proves its configuration still references the old image version. The output is trimmed, and the ReplicaSets will have different names. ...