Sample deploy.json file used in https://www.linkedin.com/pulse/learners-guide-deploying-docker-ecs-using-gitlab-ci-vaibhav-thakur/ . family and containerDefinitions.name are also generated when you create first ecs deployment from the console.

sample-ecs-deploy.json

{
  "containerDefinitions": [
    {
      "memory": 600,
      "portMappings": [
        {
          "hostPort": 0,
          "containerPort": 3000,
          "protocol": "tcp"
        },
        {
          "hostPort": 0,
          "containerPort": 22,
          "protocol": "tcp"
        },
        {
          "hostPort": 0,
          "containerPort": 6379,
          "protocol": "tcp"
        }
      ],
      "environment": [
        {
          "name": "NODE_ENV",
          "value": "N_ENV"
        }
      ],
      "essential": true,
      "name": "<container-name>",
      "image": "<your-docker-registry>/REPO:TAG",
      "cpu": 512,
      "memoryReservation": 300
    }
  ],
  "family": "<service-name>"
}