Step 2: Create the AppSpec file

To create your AppSpec file

1. If you want to create your AppSpec file using YAML, create a file named appspec.yml. If you want to create your AppSpec file using JSON, create a file named appspec.json.

2. Choose the appropriate tab, depending on if you use YAML or JSON for your AppSpec file, and copy its content into the AppSpec file you just created. For the TaskDefinition property, use the task definition ARN you noted in Step 1: Update your Amazon ECS application section.

   JSON AppSpec

   {
     "version": 0.0,
     "Resources": [
       {
         "TargetService": {
           "Type": "AWS::ECS::Service",
           "Properties": {
             "TaskDefinition": "arn:aws:ecs:aws-region-id:aws-account-id:task-definition/ecs-demo-task-definition:revision-number",
             "LoadBalancerInfo": {
               "ContainerName": "your-container-name",
               "ContainerPort": your-container-port
             }
           }
         }
       }
     ]
   }

   YAML AppSpec

   version: 0.0
   Resources:
     - TargetService:
         Type: AWS::ECS::Service
         Properties:
           TaskDefinition: "arn:aws:ecs:aws-region-id:aws-account-id:task-definition/ecs-demo-task-definition:revision-number"
           LoadBalancerInfo:
             ContainerName: "your-container-name"
             ContainerPort: your-container-port

   Note

   Your replacement task set inherits the subnet, security group, platform version, and assigned public IP values from your original task set. You can override these values for your replacement task set by setting their optional properties in your AppSpec file. For more information, see AppSpec 'resources' section for Amazon ECS deployments and AppSpec File example for an Amazon ECS deployment .

3. Upload your AppSpec file to the S3 bucket you created as a prerequisite for this tutorial.