Continuous integration, delivery and deployment

Scenario:

Mono-repo with multiple projects hosted on github.. We need a CI/CD setup for this, whenever a pull request is raised.

Inputs:

• Code hosted on Github

Continuous Integration/CI server:

• CI server shall merge incoming branch into master in its environment, when a pull request is made.
• Run unit tests
• Run integration tests
• Gives an endpoint for the pull request owner to manually validate integration

Steps:

• git merge
• <code_base>
• <code_base>
• Bring up necessary infra
• <integration_test> <code_base>
• if all pass, push the binaries to artefact storage.

Continuous Delivery:

• The server bakes the binaries into a ready to use AMI or image. This step shall also create auto-scaling group, launch template, etc. necessary for service to function for end user.

Steps:

• Provision new AMI using packer, with latest binary from earlier step.
• Invoke terraform script to create launch template, auto-scaling group, target group, etc.
• It responds to jenkins server when the delivery is ready for deployment.

Continuous Deployment:

Note: Anywhere it says, “attach to load balancer” can be perceived as “registered to service discovery” for that architecture.

• The server takes manual command from service owner, attaches the auto-scaling group to load balancer.
• Allows user to terminate older deployment after a few minutes..Typically greater than time_taken_to_launch_server+time_taken_to_initialise_process+minimum_healthy_threshold*interval
• Once done, notifies monitoring system about new deployment.

Steps:

• Gets current autoscaling group id from above step
• Adds them to defined load balancer
• Awaits for load balancer stats on health, asks for termination
• Terminates older infra upon confirmation