Rolling Updates and Rollbacks in Kubernetes
What are rolling updates and rollbacks? How are they done on Kubernetes?
Rolling updates incrementally update pods behind the scenes with new software versions without downtime. Rollbacks revert changes and restore previous stable versions after issues emerge. Kubernetes manages both automatically using declarative configuration.
When are rolling updates in Kubernetes useful?
Rolling updates shine for continuously deployed applications and systems requiring high uptime during updates, like e-commerce and banking. They minimize downtime risks.
How does Kubernetes perform rolling updates?
Kubernetes uses ReplicaSets to maintain parallel old and new pod groups, then shifts traffic from old pods to new ones in batches while checking health metrics.
What common issues prompt rollbacks of Kubernetes deployments?
Bugs, performance problems from spikes in traffic, broken workflows, crashes, scaling problems, security issues, failed integration with other updated services, etc.
How fast should updates roll out?
Start slow with reasonable pacing between pod batch updates, especially for big changes. Observe monitoring dashboards for issues. Optimizing rollout speeds comes later.
What safeguards help catch update problems early?
Readiness/liveness checks, health endpoints, synthetic monitoring, dashboards with metrics and logs visibility, automated alerts, and manually verifying functionality.
What deployment patterns complement rolling updates?
Canary testing, blue-green environments, and using feature flags to toggle on/off new functionality. All minimize risk.
Rolling Updates and Rollbacks in Kubernetes: Managing Application Updates
Many websites and apps now run on clusters of computers called containers. Containers let apps run smoothly as groups work on updating and improving the software behind the apps. A system called Kubernetes helps manage and update all those containerized apps. Sometimes app updates go wrong or cause problems for users. Kubernetes has clever ways to update apps that avoid issues.
The main method is called a rolling update. This slowly switches the software behind the scenes from an old version to a new one. A few containers at a time are updated to the new software. Kubernetes checks that each small batch works fine before updating more. This means no downtime for users! Another useful capability is rollbacks. If a new software version causes glitches, Kubernetes can automatically revert to the previous stable version. There is no need for websites to crash or stay broken!