Deployment Strategy Blue Green

Overview

Use this skill to design low-risk cutovers between two production environments with clear rollback paths.

Scope Boundaries

• Use this skill when the task matches the trigger condition described in description.
• Do not use this skill when the primary task falls outside this skill's domain.

Shared References

• Data/schema compatibility guidance:
  • references/blue-green-data-compatibility.md

Templates And Assets

• Cutover runbook template:
  • assets/blue-green-cutover-runbook-template.md
• Readiness checklist:
  • assets/blue-green-readiness-checklist.md

Inputs To Gather

• Service criticality and acceptable deployment interruption.
• Data/schema compatibility constraints between old/new versions.
• Traffic switching mechanism (LB, DNS, gateway, mesh).
• Health/SLO guardrails and rollback authority.

Deliverables

• Blue-green rollout and cutover plan.
• Readiness checklist for green environment.
• Rollback trigger matrix and execution runbook.
• Post-cutover verification checklist.

Quick Cutover Example

1. Deploy to green and run smoke + synthetic checks.
2. Mirror a small read-only validation traffic slice.
3. Switch 100% traffic at cutover window.
4. Rollback immediately if p95/error guardrails breach for N minutes.

Quality Standard

• Green environment parity is validated before switch.
• Cutover decision uses explicit health/SLO criteria.
• Rollback path is operationally tested and time-bounded.
• Stateful compatibility risks are mitigated in advance.

Workflow

1. Define cutover/rollback criteria and owners.
2. Validate environment parity and dependencies using assets/blue-green-readiness-checklist.md.
3. Execute pre-cutover verification in green and capture steps in assets/blue-green-cutover-runbook-template.md.
4. Perform controlled traffic switch.
5. Monitor guardrails and either stabilize or rollback.
6. Decommission blue only after stabilization window.

Failure Conditions

• Stop when rollback cannot be executed within required recovery time.
• Stop when data/schema compatibility between blue/green is unresolved.
• Escalate when guardrails are missing for critical user paths.