What Are the Key kubectl rollout Commands?

Detailed Answer

The kubectl rollout command group manages the lifecycle of Deployments (and DaemonSets and StatefulSets). These commands are essential for day-to-day operations and are heavily tested in CKA and CKAD exams.

kubectl rollout status

Monitors the progress of a rollout in real-time:

kubectl rollout status deployment/web
# Waiting for deployment "web" rollout to finish: 2 out of 3 new replicas have been updated...
# deployment "web" successfully rolled out

Use the --timeout flag in CI/CD pipelines to fail the pipeline if the rollout takes too long:

kubectl rollout status deployment/web --timeout=120s
# If the rollout does not complete in 120 seconds, the command exits with code 1

The --watch flag (on by default) streams updates. Use --watch=false for a point-in-time check.

kubectl rollout history

Shows the revision history of a Deployment:

kubectl rollout history deployment/web
# REVISION  CHANGE-CAUSE
# 1         Initial deployment
# 2         Upgraded to v2.0
# 3         Added resource limits

View details of a specific revision:

kubectl rollout history deployment/web --revision=2
# Pod Template:
#   Labels: app=web, pod-template-hash=abc123
#   Containers:
#    nginx:
#     Image: nginx:2.0

The number of revisions stored is controlled by spec.revisionHistoryLimit (default: 10).

kubectl rollout undo

Rolls back to a previous revision:

# Roll back to the immediately previous revision
kubectl rollout undo deployment/web

# Roll back to a specific revision
kubectl rollout undo deployment/web --to-revision=2

This command creates a new rollout that uses the Pod template from the target revision. It is the fastest way to respond to a bad deployment in production.

kubectl rollout pause and resume

Pause a rollout to hold it at its current state:

# Pause the rollout
kubectl rollout pause deployment/web

# Make multiple changes without triggering individual rollouts
kubectl set image deployment/web nginx=nginx:1.28
kubectl set resources deployment/web -c nginx --limits=cpu=500m,memory=512Mi

# Resume to apply all changes as a single rollout
kubectl rollout resume deployment/web

Pausing is useful for:

• Batching changes: Make multiple spec changes and apply them as one rollout
• Manual canary verification: Pause after partial rollout to observe behavior
• Maintenance windows: Prevent rollouts during sensitive periods

kubectl rollout restart

Triggers a rolling restart of all Pods without changing the Deployment spec:

kubectl rollout restart deployment/web

Behind the scenes, this adds a kubectl.kubernetes.io/restartedAt annotation with the current timestamp to the Pod template. Since the template changed, a new rollout begins.

Common use cases:

• Picking up new ConfigMap or Secret values (when not using immutable references)
• Refreshing container images when using latest tag (not recommended but common)
• Recovering from an unknown state

Complete Command Reference

| Command | Purpose | Example | |---------|---------|---------| | rollout status | Check rollout progress | kubectl rollout status deploy/web | | rollout history | View revision history | kubectl rollout history deploy/web | | rollout undo | Roll back | kubectl rollout undo deploy/web | | rollout pause | Freeze rollout | kubectl rollout pause deploy/web | | rollout resume | Continue paused rollout | kubectl rollout resume deploy/web | | rollout restart | Trigger rolling restart | kubectl rollout restart deploy/web |

Practical Workflow Example

A typical deployment and rollback workflow:

# 1. Deploy a new version
kubectl set image deployment/web nginx=nginx:1.28

# 2. Monitor the rollout
kubectl rollout status deployment/web --timeout=120s

# 3. If something goes wrong, roll back immediately
kubectl rollout undo deployment/web

# 4. Verify the rollback
kubectl rollout status deployment/web

# 5. Check which revision is now active
kubectl rollout history deployment/web

Using rollout in Scripts

#!/bin/bash
# CI/CD deployment script

# Apply the new manifest
kubectl apply -f deployment.yaml

# Wait for rollout to complete
if ! kubectl rollout status deployment/web --timeout=300s; then
  echo "Rollout failed — rolling back"
  kubectl rollout undo deployment/web
  kubectl rollout status deployment/web --timeout=120s
  exit 1
fi

echo "Deployment successful"

Supported Resource Types

The kubectl rollout commands work with:

• Deployments — full rollout management
• DaemonSets — rolling update support
• StatefulSets — ordered rolling updates

They do not work with bare Pods, ReplicaSets, or Jobs.