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Automating a CI/CD Pipeline with AWS DevOps

Components of AppSpec YAML File

Explore the key components of the AppSpec YAML file used in AWS CodeDeploy to manage deployment lifecycle events. Understand sections like version, os, resources, files, and hooks that define deployment configurations for EC2, ECS, and Lambda environments. This lesson helps you validate and prepare robust deployment specifications.

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AWS CodeDeploy uses a configuration file named appspec.yml to manage each deployment. This deployment file can be written in YAML or JSON. An essential requirement we need to keep in mind is that each deployment must have a unique application specification file.

AppSpec YAML file structure

A common theme we must remember while preparing this configuration file is that it has a series of key-value pairs. Even if the value is of a type string, we don’t need to enclose it in double quotation marks.

YAML
version: 0.0
os: linux
resources:
  - TargetService:
      Type: AWS::ECS::Service
      Properties:
        TaskDefinition: arn-of-task-definition
        LoadBalancerInfo:
          ContainerName: application name
          ContainerPort: 80
files:
  - source: /
    destination: /home/ec2-user/server
hooks:
  ApplicationStart:
    - location: server_start.sh
      runas: ec2-user
  ApplicationStop:
    - location: server_stop.sh
      runas: ec2-user
  BeforeInstall:
    - location: before_install.sh
      runas: ec2-user

version: This is a required section. The default and the only allowed value is 0.0. CodeDeploy will use this value to reference new versions as they modify the specification file.

os: This section specifies the operating system name where the application will be deployed. Possible values are:

  • linux: Represents Ubuntu and Amazon Linux. ...