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
