AWS ECS Provisioning scripts for Travis CI

This module contains a set of scripts for automatic building, pushing, and deploying of a Dockerized app to AWS ECS using Travis CI.

Project setup

The scripts assumes that your are set up in the following way.

Environments and Git Branches

Use one git branch per environment you want to deploy, e.g. production, master. Travis makes the built branch name available through the $TRAVIS_BRANCH environment variable, which is used in the scripts.

ECS Repositories, Clusters, and Services

Create an ECS Repository for storing the project's Docker image. Take note of the Repository ARN and Repository URI.

Create one ECS Task Definition for each of the environments. The Task Definition should use the image from the created ECS Repository tagged with the branch/environment name.

Create one ECS Cluster per environment you want to deploy. The cluster can be shared among several projects, for example if the project consists of a separate frontend and backend. Both projects can use the same clusters, but different services in the clusters. The cluster names are configurable with environment variables (see below).

Create an ECS Service in the Cluster for keeping the Task running.

AWS User

Create an IAM User that has permission to use ECR, ECS and logging services. Use the following Permission Policy for granting the user needed access:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "ecr:BatchCheckLayerAvailability",
                "ecr:BatchGetImage",
                "ecr:GetDownloadUrlForLayer",
                "ecr:GetAuthorizationToken",
                "ecs:List*",
                "ecs:Describe*",
                "ecs:RegisterTaskDefinition",
                "ecs:UpdateService",
                "ecs:CreateCluster",
                "ecs:DeregisterContainerInstance",
                "ecs:DiscoverPollEndpoint",
                "ecs:Poll",
                "ecs:RegisterContainerInstance",
                "ecs:StartTelemetrySession",
                "ecs:Submit*",
                "logs:CreateLogStream",
                "logs:PutLogEvents"
            ],
            "Resource": "*"
        },
        {
            "Effect": "Allow",
            "Action": [
                "ecr:GetAuthorizationToken",
                "ecr:BatchCheckLayerAvailability",
                "ecr:GetDownloadUrlForLayer",
                "ecr:GetRepositoryPolicy",
                "ecr:DescribeRepositories",
                "ecr:ListImages",
                "ecr:DescribeImages",
                "ecr:BatchGetImage",
                "ecr:InitiateLayerUpload",
                "ecr:UploadLayerPart",
                "ecr:CompleteLayerUpload",
                "ecr:PutImage"
            ],
            "Resource": [
                "REPOSITORY_ARN"
            ]
        }
    ]
}

Replace REPOSITORY_ARN with the ARN for the ECR repository/repositories you want to deploy.

Create an Access Key for the user and store the Access key ID and Secret access key in a safe place.

Configuring the project

The scripts are configured through environment variables that are made available to the Travis build environment.

NOTE: Sensitive information such as access keys should be encrypted using Travis CLI. See Defining encrypted variables in .travis.yml for instructions.

The following environment variables must be defined and made available to the Travis build process

Name	Description
IMAGE_NAME	The name of the Docker image to build, e.g. some-project
DEPLOY_BRANCHES	Space delimited list of branches to deploy, e.g. "master production"
AWS_REGION	The region where your ECS services are created, e.g. eu-central-1
AWS_ACCESS_KEY_ID	The IAM User's Access key ID
AWS_SECRET_ACCESS_KEY	The IAM User's Secret access key
REMOTE_IMAGE_URL	The ECS Repository image URL (<id>.dkr.ecr.<region>.amazonaws.com/some-project)

In addition, a set of the following environment variables must be defined for each branch/environment you want to deploy:

Name	Description
ECS_CLUSTER_BRANCH_NAME	The name of the ECS Cluster for the BRANCH_NAME, e.g. ECS_CLUSTER_MASTER
ECS_SERVICE_BRANCH_NAME	The name of the ECS Service for the BRANCH_NAME, e.g. ECS_SERVICE_MASTER

package.json

Add the following npm/yarn script to your package.json

{
    "scripts": {
        "travis-ecs-deploy": "travis-ecs-deploy"
    }
}

.travis.yml

The environment variables are typically defined in the .travis.yml file which defines the CI process in Travis. Add the following configuration to the end of your .travis.yml file (here shown with encrypted variables, original values as comments):

env:
  global:
    - IMAGE_NAME=simple-todo
    - DEPLOY_BRANCHES=master
    - AWS_REGION=eu-central-1
    # AWS_ACCESS_KEY_ID=83460cadb90f034be815
    - secure: "CDvpSjbywrGbrcFx0lwbkjf3..."
    # AWS_SECRET_ACCESS_KEY=73ebce91f95d4939805b-3d1ba967c59d9ba9a7b7701a436ca04d-a0aa972e6642
    - secure: "trVDrcNP+NVBCB0BFwoaDxkH..."
    # REMOTE_IMAGE_URL=648568381338.dkr.ecr.eu-central-1.amazonaws.com/simple-todo
    - secure: "T0303bikzHpHNKIVJekS3yBS..."
    - ECS_CLUSTER_MASTER=simple-todo-master
    - ECS_SERVICE_MASTER=simple-todo

deploy:
  skip_cleanup: true
  provider: script
  script:
    - yarn run travis-ecs-deploy   # or "npm run travis-ecs-deploy"
  on:
    all_branches: true

Example

In this example we'll go through the setup for a typical project called simple-todo.

Git Branches

The git repository will have two deployable branches, master and production. Both branches are deployed whenever changes are pushed to the branches.

ECS Repository

An ECS Repository simple-todo is created. The repository's ARN and URI are

• ARN: arn:aws:ecr:eu-central-1:648568381338:repository/simple-todo
• URI: 648568381338.dkr.ecr.eu-central-1.amazonaws.com/simple-todo

ECS Task Definition

Two ECS Task Definitions simple-todo-master and simple-todo-prod are created. They use the following image identifiers:

• Simple todo master: 648568381338.dkr.ecr.eu-central-1.amazonaws.com/simple-todo:master
• Simple todo prod: 648568381338.dkr.ecr.eu-central-1.amazonaws.com/simple-todo:production

ECS Clusters and Services

Two ECS Clusters simple-todo-master and simple-todo-prod are created. Each of them contain one service simple-todo, that is configured to run the task definition for the corresponding branch. I.e.:

Cluster 'simple-todo-master'
 `- Service 'simple-todo'
    `- Runs Task Definition 'simple-todo-master'

Cluster 'simple-todo-prod'
 `- Service 'simple-todo'
    `- Runs Task Definition 'simple-todo-prod'

IAM User

An IAM User simple-todo-travis is created with the above policy and an Access key is generated:

• Access key ID: 83460cadb90f034be815
• Secret access key: 73ebce91f95d4939805b-3d1ba967c59d9ba9a7b7701a436ca04d-a0aa972e6642

Acknowledgements

• ecs-deploy - shell script for initiating blue-green deployments on AWS ECS