CI/CD

• CI/CD architecture:
• Branching architecture:
• Code pipeline:
• Each pipeline has stages
• Each pipeline should be linked to a single branch in a repository
• CodeBuild/CodeDeploy configuration files:
  • buildspec.yml, appspec.[yml|json]
  • Reference to these files: https://docs.aws.amazon.com/codedeploy/latest/userguide/reference-appspec-file.html
  • buildspec is used to influence the way the build process occurs within CodeBuild
  • appspec allows the influence how the deployment process proceeds in CodeDeploy

AWS CodeCommit

• Managed git service
• Basic entity of CodeCommit is a repository
• Authentication can be configured via IAM console. CodeCommit supports HTTPS, SSH and HTTPS over GRPC
• Triggers and notifications:
  • Notifications rules: can send notifications based on events happening in the repo, example: commits, pull request, status changes, etc. Notifications can be sent to SNS topics or AWS chat bots
  • Triggers: allow the generate event driven processes based on things that happen in the repo. Events can be sent ot SNS or Lambda functions

AWS CodePipeline

• It is a Continuos Delivery tool
• Controls the flow from source code, through build towards deployment
• Pipelines are built from stages. Stages contain actions which can be sequential or parallel
• Movement between stages can happen automatically or it can require a manual approval
• Actions within stages can consume artifacts or they can generate artifacts
• Artifacts are just files which are generated and/or consumed by actions
• Any changes to the sate of a pipeline, stages or actions generate events which are published to Event Bridge
• CloudTrail can be used to monitor API calls. Console UI can be used to view/interact with the pipeline

AWS CodeBuild

• CodeBuild is a build as a service product
• It is fully managed, we pay only for the resources consumed during builds
• CodeBuild is an alternative to the solutions provided by third party solutions such as Jenkins
• CodeBuild uses Docker for build environments which can be customized by us
• CodeBuild integrates with other AWS services such as KMS, IAM, VPC, CloudTrails, S3, etc.
• Architecturally CodeBuild gets source material from GitHub, CodeCommit, CodePipeline or even S3
• It builds and tests code. The build can be customized via buildspec.yml file which has to be located in the root of the source Remember the spelling of file and location for EXAM
• CodeBuild output logs are published to CloudWatch Logs, metrics are also published to CloudWatch Metrics and events to Event Bridge (or CloudWatch Events)
• CodeBuild supports build environments such as Java, Ruby, Python, Node.JS, PHP, .NET, Go and many more

buildspec.yml

• It is used to customize the build process
• It has to be located in root folder of the repository
• It can contain four main phases:
  • install: used to install packages in the build environment
  • pre_build: sign-in to things or install code dependencies
  • build: commands run during the build process
  • post_build: used for packaging artifacts, push docker images, explicit notifications
• It can contain environment variables: shell, variables, parameter-store, secret-manager variables
• Artifacts part of the file: specifies what stuff to put where

AWS CodeDeploy

• Is a code deployment as a service product
• It is an alternative for third-party services such as Jenkins, Ansible, Chef, Puppet or even CloudFormation
• It is used to deploy code, not resources (use CloudFormation for that)
• Uses docker for build environments, it can be customized
• CodeDeploy can deploy code to EC2, on-premises, Lambda and ECS
• Besides code, it can deploy configurations, executables, packages, scripts, media and many more
• CodeDeploy integrates with other AWS services such as KMS, IAM, VPC, CloudTrail, S3
• In order to deploy code on EC2 and on-premises, CodeDeploy requires the presence of an agent

appspec.[yaml|json]

• It controls how deployments occur on the target
• Manages deployments: configurations + lifecycle event hooks
• Configuration section - has 3 important sections:
  • Files: applies to EC2/on-premises. Provides information about which files should be installed on the instance
  • Resources: applies to ECS/Lambda. For Lambda it contains the name, alias, current version and target version of a Lambda function. For ECS contains things like the task definition and container details (ports, traffic routing)
  • Permissions: applies to EC2/on-premises. Details any special permissions and how should be applies to files and folders from the files sections
• Lifecycle event hooks:
  • ApplicationStop: happens before the application is downloaded. Used for gracefully stop the application
  • DownloadBundle: agent copies the application to a temp location
  • BeforeInstall: used for pre-installation tasks
  • Install: agent copies the application from the temp folder to the final location
  • AfterInstall: perform post-install steps
  • ApplicationStart: used to restart/start services which were stopped during the ApplicationStop hook
  • ValidateService: verify the deployment was completed successfullyRemember for EXAM