Blue-Green Deployment Flowchart with Rollback Path

Mermaid code

flowchart TD
    U[Users] --> R[Router / load balancer]
    R -->|100% traffic| B[Blue environment<br/>current release]
    N[New release] --> G[Green environment<br/>idle]
    G --> H{Health checks pass?}
    H -->|yes| S[Switch router to green]
    H -->|no| F[Fix and redeploy to green]
    F --> G
    S --> M[Monitor error rate]
    M -->|stable| D[Decommission blue]
    M -->|regression| RB[Switch router back to blue]
    RB --> F

Paste this into any tool that renders Mermaid, or into the editor to change the theme and export PNG or SVG. Syntax reference: Flowchart guide.

What this diagram shows

Here Blue environment serves all traffic while New release lands on the idle Green environment. The Health checks pass? diamond gates the Switch router to green step. After the switch, Monitor error rate decides whether blue is decommissioned or the router flips back. The rollback edge RB --> F shows that a reverted release goes back to the fix loop rather than being abandoned.

How to adapt it

• Replace Router / load balancer with the component that actually moves traffic for you, such as a DNS record, an ingress controller, or a service mesh.
• Add a Run smoke tests node between Green environment and the health check diamond if you run synthetic tests before exposing real users.
• For canary releases, change 100% traffic to 95% traffic on blue and add a 5% traffic edge from the router to green.
• Swap Decommission blue for Keep blue as standby if you leave the old environment running until the next release.

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