How to Check Rollout History in Kubernetes

Use the kubectl rollout history command followed by the resource type and name to view the rollout history of a Kubernetes deployment. For example, kubectl rollout history deployment/my-deployment shows all revisions and changes made to that deployment.

Syntax

The basic syntax to check rollout history in Kubernetes is:

• kubectl rollout history <resource_type>/<resource_name>: Shows the rollout history of the specified resource.
• --revision=<number>: Optional flag to view details of a specific revision.

bash

kubectl rollout history deployment/my-deployment
kubectl rollout history deployment/my-deployment --revision=2

Example

This example shows how to check the rollout history of a deployment named nginx-deployment and view details of revision 3.

bash

kubectl rollout history deployment/nginx-deployment
kubectl rollout history deployment/nginx-deployment --revision=3

Output

deployment.apps/nginx-deployment 
REVISION  CHANGE-CAUSE
1         Initial deployment
2         Updated image to nginx:1.19
3         Updated image to nginx:1.20

deployment.apps/nginx-deployment with revision #3
Pod Template:
  Containers:
    nginx:
      Image: nginx:1.20
      Port: 80/TCP

Common Pitfalls

Common mistakes when checking rollout history include:

• Using the wrong resource type (e.g., pod instead of deployment).
• Not specifying the resource name correctly.
• Expecting rollout history for resources that do not support it (only deployments, daemonsets, and statefulsets support rollout history).
• Forgetting to use --revision to see details of a specific revision.

bash

kubectl rollout history pod/nginx-pod
# Wrong resource type, will show error

kubectl rollout history deployment/nginx-deployment --revision=100
# Revision does not exist, will show error

Quick Reference

Command	Description
kubectl rollout history deployment/	Show rollout history of a deployment
kubectl rollout history deployment/ --revision=	Show details of a specific revision
kubectl rollout undo deployment/	Rollback to previous revision
kubectl rollout status deployment/	Check current rollout status

Key Takeaways

Use 'kubectl rollout history deployment/' to see all revisions of a deployment.

Add '--revision=' to view details of a specific rollout revision.

Rollout history works for deployments, daemonsets, and statefulsets only.

Ensure you specify the correct resource type and name to avoid errors.

Use rollout history to track changes and troubleshoot deployment rollbacks.