Blue Green Streamlined

Implement blue-green deployment with automated traffic switching, health validation, and instant rollback capability.

When to Use This Command

Run this command when you need to:

• Deploy a new application version alongside the current one and switch traffic with zero downtime
• Validate a new deployment against health checks and smoke tests before exposing it to users
• Roll back instantly to the previous version by switching traffic back to the original environment

Consider alternatives when:

• You want gradual traffic shifting (use canary deployment instead)
• Your application cannot run two versions simultaneously due to database schema incompatibility

Quick Start

Configuration

Copy
name: blue-green-streamlined
type: command
category: deployment

Example Invocation

Copy
claude command:run blue-green-streamlined --version v2.1.0 --target green --platform k8s

Example Output

[Detect] Current active: BLUE (v2.0.0) | Idle: GREEN
[Deploy] Deploying v2.1.0 to GREEN environment...
  Image: myapp:v2.1.0 pulled (234 MB)
  Pods: 3/3 ready (42s)

[Validate] Running health checks on GREEN...
  /health: 200 OK (45ms)
  /ready: 200 OK (38ms)
  Smoke tests: 12/12 passed

[Switch] Routing traffic from BLUE to GREEN...
  Load balancer updated: 100% traffic -> GREEN
  DNS propagation: confirmed (2s)

[Monitor] Watching error rates for 60s...
  Error rate: 0.02% (baseline: 0.03%) -- OK

[Complete] GREEN (v2.1.0) is now active
[Rollback] To revert: claude command:run blue-green-streamlined --rollback

Core Concepts

Blue-Green Deployment Overview

Aspect	Details
Environments	Two identical environments (Blue and Green) alternating as active/idle
Traffic Switch	Atomic swap via load balancer, DNS, or Kubernetes service selector
Validation	Health checks, smoke tests, and error rate monitoring before switch
Rollback	Instant revert by switching traffic back to the previous environment

Deployment Workflow

[BLUE = Active] [GREEN = Idle]
       |
[Deploy new version to GREEN]
       |
[Health checks + smoke tests]
       |
[Switch traffic: BLUE -> GREEN]
       |
[Monitor error rates]
    /       \
  OK       Problem
   |          |
[GREEN=Active] [Rollback to BLUE]

Configuration

Parameter	Type	Default	Description
version	string	required	Application version tag to deploy
target	string	auto	Target environment: blue or green (auto-selects idle)
platform	string	k8s	Deployment platform: k8s, docker-swarm, ecs, or nginx
monitor-duration	number	60	Seconds to monitor error rates after traffic switch
rollback	boolean	false	Revert to the previously active environment

Best Practices

1. Validate Exhaustively Before Switching - Run comprehensive health checks, smoke tests, and integration tests against the idle environment before routing any user traffic. The cost of validation is always less than the cost of a bad deployment.

2. Monitor After Switch, Not Just Before - Error rates may spike only after real user traffic hits the new version. Watch metrics for at least 60 seconds after the switch before declaring success.

3. Keep Both Environments Running Post-Switch - Do not tear down the old environment immediately. Keep it running for at least one business cycle (24 hours) to enable instant rollback if delayed issues surface.

4. Ensure Database Compatibility - Both blue and green must work against the same database. Design migrations to be backward-compatible so the old version continues to function during the transition window.

5. Automate the Entire Flow - Manual traffic switching introduces human error. Script the deploy-validate-switch-monitor pipeline end-to-end and only intervene on failure.

Common Issues

1. Session Stickiness Breaks After Switch - User sessions tied to the old environment lose state after traffic moves. Use external session storage (Redis, database) instead of in-memory sessions.

2. Health Check Passes but Application Fails - Superficial health endpoints that return 200 without checking dependencies give false confidence. Ensure health checks verify database connectivity, cache access, and critical services.

3. DNS Propagation Delay - DNS-based switching has inherent propagation delays. Use load balancer or Kubernetes service selector switching for instant cutover without DNS dependency.