Day 50: Cloud pattern: Blue/Green deployment
Blue/green deploy is a deployment process without downtime, that make rollback simple:
- v1.0.0 running on 10 instances
- start 10 instances of v1.0.1
- when every new instances are up, ask to the load balancer to route the traffic onto v1.0.1
- if everything is working web, destroy old instances (v1.0.0), else, ask the load balancer to route the traffic back onto v1.0.0
Migrations should be made before deploying v1.0.1 and database schema must be compatible with v1.0.0.