Turquoise

Turquoise is a CLI utility for performing blue-green deploys on AWS Auto Scaling Groups. When invoked, it will create a new auto scaling group with the specified AMI, wait until all instances have booted and are passing health checks (including ELB health checks if applicable), and the delete the old auto scaling group.

Although Amazon CloudFormation has a rolling update feature for auto scaling groups, it does not take into account ELB health checks, which can cause periods where no instances registered in the load balancer are healthy, leading to downtime.

Usage

You'll need two things to use Turquoise: a base name and an AMI.

The base name is an string of your choosing. Turquoise will use the base name to construct a name for the new auto scaling group. The new name is the base name plus a hyphen plus the current unix timestamp. For example, if your base name is my-asg, a new auto scaling name might be my-asg-1459314750.

The base name will also be used to find the current auto scaling group. Turquoise will search for auto scaling groups that a name equal to the base name or a valid name constructed from the base name. If multiple auto scaling groups are found, the one with the latest timestamp will be used.

To obtain an AMI ID, we recommend using Packer to automate building an AMI. However, any valid AMI will work.

With those in hand, using Turquoise is easy:

turquoise [base name] [ami id]

Turquoise uses boto, so you can authenticate yourself with AWS using the credentials file or environment variables.

Give it a few minutes to finish running and you'll have a new auto scaling group running instances with your new AMI.