Best Practices for Rolling Updates
Kubernetes makes it easier than ever to smoothly upgrade apps. But some planning and care still makes the process less risky. Here are some best practices:
Deployment Patterns
The basic rolling update works fine. More advanced patterns add extra safety nets:
- Blue-Green: Launch the new version separately first before retiring the old version. Route a little bit of traffic to the new environment to stage a soft launch. If issues emerge, no impact, just send all traffic back to the old version still intact!
- Canary: Similar idea, slowly send an increasing percentage of traffic to the new version. Watch metrics carefully with each ramp-up. Rollback or pause easily if needed.
Rollout Pace & Checks
Take it slow, especially for big changes! Complex new microservices or dramatic rearchitecting deserves a gradual and cautious rollout:
- Max Unavailable: Keep this low, maybe just 10% of pods updating at once
- Max Surge: Allow a buffer of maybe 2 extra pods to handle traffic spikes
- Readiness Checks: Ensure new pods work before sending them live traffic
- Monitor Closely
- Watch health metrics for individual pods and overall workload:
- Resource Usage: CPU, RAM, disk fills
- Application Metrics: Response times, error rates
- Logs: Errors, warnings, stack traces indicating bugs
- Dashboards centralize all this into clear views to base rollback decisions on.
- Implement Health Checks
- Make sure the app itself reports failures and self-heals using:
- Liveness Probes: Did container crash unexpectedly? Restart it!
- Readiness Checks: Is app ready to receive traffic after starting up?
This takes pressure off Kubernetes to detect issues.
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!