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Blue-Green Synchronized Deployments in Porter

Porter supports Blue-Green synchronized deployments to help you coordinate the rollout of tightly coupled applications. This guide explains how to configure and use this feature.

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What is a Blue-Green Synchronized Deployment?

Blue-Green deployment is a strategy that maintains two identical environments (blue and green) to minimize downtime and risk during application updates:
  • The blue environment is the currently active production environment
  • The green environment is the new version being deployed
With Porter’s synchronized Blue-Green deployments, you can coordinate multiple applications that need to be deployed together as a single unit. This is particularly useful for:
  • Microservices architectures where APIs must stay compatible
  • Frontend and backend components that need to maintain version compatibility
  • Any group of applications that must be deployed in sync to function properly

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Configuring Blue-Green Deployments

You can configure Blue-Green deployment synchronization in two ways: through your porter.yaml file or via the Porter dashboard.

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Configuration in porter.yaml

To enable Blue-Green deployments, add the deploymentStrategy section to your porter.yaml for each application you want to include in the synchronized group: 
version: v2
name: frontend
services:
- name: web
  run: node index.js
  type: web
  instances: 1
  ...
build:
  context: ./
  method: docker
  dockerfile: ./Dockerfile
deploymentStrategy:
  kind: blueGreen
  blueGreen:
    group: [name-for-the-group]
Key configuration points:
  • Set deploymentStrategy.kind to blueGreen
  • Use the blueGreen.group field to specify a group name
  • All applications with the same group name will be deployed together
  • Make sure all applications in the group are deployed with the same image tag

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Configuration in the Porter Dashboard

You can also configure Blue-Green deployments directly in the Porter dashboard:
  1. Navigate to your application dashboard
  2. Go to the “Settings” tab
  3. Find the “Blue-Green Deployment Group” section
  4. Select an existing group from the dropdown or type a new group name
  5. Save your changes
Blue-Green Configuration in Dashboard Blue-Green deployment group configuration in application settings

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Understanding Blue-Green Deployment Status

When you deploy applications that are part of a Blue-Green group, the Porter dashboard will show detailed status information in the Activity feed. Blue-Green Status in Activity Feed Blue-Green deployment status displayed in the Activity feed

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Requirements and Limitations

For Blue-Green synchronized deployments to work correctly:
  1. Same Image Tag Requirement: All applications in a Blue-Green group must be deployed with the same image tag. This is typically the commit SHA for applications deployed from GitHub. If you have a mono repo and your apps are deployed from the same branch, the default workflow files created by Porter should be comaptible with this feature.
  2. Deployment Time Window: All applications in a group must complete their deployment within a 20 min time window with the same image tag. If one application fails to deploy or takes too long, the entire group deployment is considered failed and reverted.

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Example Use Case

Consider a scenario with a frontend application and its backend API that must stay compatible:
  1. Configure both applications with the same Blue-Green group:
# backend/porter.yaml
version: v2
name: backend
services:
- name: web
  run: python server.py
  type: web
  instances: 1
  ...
build:
  context: ./
  method: docker
  dockerfile: ./Dockerfile
deploymentStrategy:
  kind: blueGreen
  blueGreen:
    group: primary


# frontend/porter.yaml
version: v2
name: frontend
services:
- name: web
  run: node index.js
  type: web
  instances: 1
  ...
build:
  context: ./
  method: docker
  dockerfile: ./Dockerfile
deploymentStrategy:
  kind: blueGreen
  blueGreen:
    group: primary
  1. When deploying a new version, Porter will:
    • Deploy both applications simultaneously
    • Wait for all applications to be ready before promoting traffic
    • Ensure both are successful before considering the deployment complete
    • Roll back all applications if any of them fail
  2. The dashboard will show the status of the synchronized deployment in real time, making it easy to identify any issues.
By using Blue-Green synchronized deployments, you ensure that interdependent applications are always deployed in compatible versions, reducing the risk of downtime or broken functionality due to version mismatches.