AWS › AWS CodePipeline, CodeBuild & CodeDeploy (CI/CD)

How do CodeDeploy lifecycle hooks defined in an appspec file control the deployment process?

Intermediate

Answer

An appspec file defines a series of lifecycle event hooks, such as BeforeInstall, AfterInstall, ApplicationStart, and ValidateService, each letting you run custom scripts at specific points during the deployment process, such as stopping a running application before installing new files, or running automated health check validation after the new version starts, giving you fine grained control over exactly how a deployment proceeds and how its success is verified.

version: 0.0
hooks:
  BeforeInstall:
    - location: scripts/stop_server.sh
  AfterInstall:
    - location: scripts/start_server.sh
  ValidateService:
    - location: scripts/health_check.sh

Real-world example A deployment pipeline uses a ValidateService hook that runs an automated health check script after each deployment, automatically triggering a rollback through CodeDeploy if the new version fails to respond correctly within a defined timeout.

Common follow-ups: What happens if a lifecycle hook script fails during deployment?;Can appspec files be used for both EC2 and Lambda deployments?

Monitoring (CloudWatch);Lambda & Serverless