What is Rolling Update
Gradual instance update
Rolling Update is a deployment strategy where a new application version gradually replaces the old one by updating instances one by one.
How It Works
- New instances start with the new version
- Old instances are stopped one at a time
- Traffic is redirected to ready instances
- Process continues until full update
Advantages
- Zero Downtime — service always available
- Gradual change propagation
- Ability to rollback on issues
- Minimal resource requirements
- Automation through Kubernetes
Disadvantages
- Temporary version incompatibility
- Requires backward compatibility
- Slower than Blue-Green
- Complex debugging with mixed versions
Kubernetes Parameters
- maxSurge — maximum additional pods
- maxUnavailable — allowed unavailable count
- minReadySeconds — pod readiness time
- progressDeadlineSeconds — deployment timeout