| Start GitHub Actions Workflow; |

| - Approved by Authorised Person |

| - Build AMI via Packer file |

| - Extract new AMI ID from build logs |

| - Create LT Version with the new AMI ID |

| - Trigger ASG with New Launch Template Version |

| - Start Auto Scaling Group Instance Refresh |

| AWS Auto Scaling Group |

| - Rollout new instances with updated AMI |

| - Deregister old instances |

| - Terminate old instances |

| Production app is live with new code & config |

| client / Browser |

| Application Load |

| Balancer |

| EC2 #1 |

Nginx + unicorn

| EC2 #2 |

Nginx + unicorn

| EC2 #N |

Nginx + unicorn