Pipeline Flow and Examples

Foremast generates a single pipeline per region. The pipeline is designed to allow deploying to multiple environment with checkpoints between each transition.

Default Pipeline Flow

The below flow can repeat for as many environments as defined in the configs. At Gogo, most applications go through these stages 3 times as we deploy to dev, stage, and production.

  1. Configuration
    • This stages defines the Jenkins trigger, property files, and pipeline-wide notifications
  2. Bake
    • Bakes an AMI the specified AMI ID
  3. Infrastructure Setup [$env]
    • Calls a Jenkins job to run the prepare-infrastructure Foremast command against a specific account.
    • Setups AWS infrastructure such as ELB, IAM roles, S3 bucket, and DNS needed for an application
  4. Deploy $env
    • Uses Spinnaker to create a cluster and server group in specific account.
    • The behavior of this stage is largely based on the application-master-$account.json configs.
  5. Attach Scaling Policy [$env]
  6. Checkpoint $next-env
    • A manual checkpoint stage. This requires human intervention to approve deployment to the next environment.

Stages 3-6 repeat for each environment/account defined in pipeline.json.


The default generated pipeline should look like the above image. This is the basic bake -> infrastructure -> deploy -> checkpoint pipeline described above.

Custom Pipelines

You can specify an external templates directory in foremast.cfg / config.py. Templates in an external directory will need to have the same directory structure and naming as the default templates. if templates_path is set in foremast.cfg / config.py, Foremast will first see if the file exists there. If not, it will fall back to the provided templates.

If you need to add more stages or change the defaults, this is all possible via external templates. Please the foremast-templates repo for examples on the templates.

Example Workflow

At Gogo we have a detailed workflow for using Foremast internally. Feel free to copy our workflow or use it as inspiration for your own. You can view all of our internal templates on the foremast-templates repo.

  1. The application-master-$account.json and pipeline.json are bundled directly with the application code
  2. Developer makes a change to one of those configs and pushes to the application’s git repository
  3. A server-side git hook detects a change and triggers a Jenkins job to run Foremast prepare-app-pipeline
    • Regenerates the application and pipeline in Spinnaker
  4. Build application artifacts using a Jenkins job and stored as an RPM
  5. Spinnaker triggers detect a completed Jenkins job and starts a new deployment pipeline
    1. Bake an AMI using built RPM
    2. Jenkins Stage runs Foremast prepare-infrastructure
      • Creates the AWS ELB, SG, S3 bucket, and IAM roles
    3. Jenkins Stage tags the source repository with AMI info
    4. Deploy the generated AMI to desired environments
    5. Jenkins Stage runs Quality Engineering tests against deployed application
    6. Jenkins Stage tags the source repository with deployment information
    7. Jenkins Stage attaches defined scaling policies
    8. Manual judgment before continuing to the next environment