What Environment Types Exist?

• Single instance
  • Load balancer
  • Has an elastic IP
  • Still an auto-scaling group, just has one server
• High-availability
  • Load balancer
  • ASG
  • Group of instances

Deployment types?

All at once

• “In-place” deployment
• Fast swap
• No DNS changes
• Potentially catastrophic if problems

Rolling

• Guarantee always 1 instance up at a time
• Instances detach / re-attach to load balancer (ELB)
• If it fails, it can get complicated

Rolling w/ addl batches:

• Introduce new instances before decommissioning olds
• Prevents downtime
• Requires some more overhead, time
• If failure: Original ASG is still chillin

Immutable

1. Completely new instances (prevent downtime)
2. Register new ones on ELB, do health checks
3. Kill old instances

Blue/Green

1. Create entirely new environment (incl. ELB)
2. Swap route53 URLs; use DNS to redirect traffic.

• Requires more resources
• No downtime
• Test resources in isolation
• DNS changes could be weird

Canary

• Much like blue/green—but split traffic bit by bit (via DNS)