A complete DevOps enabled sample containerized application

This project builds a complete sample containerized Flask application publically available on AWS, using Fargate, ECS, CodeBuild, and CodePipline to produce a fully functional pipline to continuously roll out changes to your new app.

We recommend using Cloud 9 to get started, however you may also use your own development machine. You will need to adjust the commands to install base requirements like jq, npm, AWS CDK, AWS CLI, and Typescript.

Launch a t2.micro Cloud9 us-east-1 terminal and prepare it with following commands:

sudo yum install -y jq
export ACCOUNT_ID=$(aws sts get-caller-identity --output text --query Account)
export AWS_REGION=$(curl -s 169.254.169.254/latest/dynamic/instance-identity/document | jq -r '.region')
echo "export ACCOUNT_ID=${ACCOUNT_ID}" | tee -a ~/.bash_profile
echo "export AWS_REGION=${AWS_REGION}" | tee -a ~/.bash_profile
aws configure set default.region ${AWS_REGION}
aws configure get default.region

Ensure the Cloud9 instance is assigned a role of an administrator and from Cloud9 -> AWS Settings -> Credentials -> Disable the Temporary Credentials

Prepare CDK prerequisite:

sudo yum install -y npm
npm install -g aws-cdk
npm install -g typescript@latest

Then, make sure you have your AWS account configured. Run aws configure or ensure the AWS_ACCESS_KEY, AWS_SECRET_ACCESS_KEY, and AWS_SESSION_TOKEN environment variables are properly set.

Open https://github.com/aws-samples/amazon-ecs-fargate-cdk-v2-cicd. Login to GitHub, and fork the repository into your account.

Access your Cloud9 environment and run the following command from the ~/environment directory, replacing USER-NAME with your GitHub username.

git clone https://github.com/USER-NAME/amazon-ecs-fargate-cdk-v2-cicd.git 

As a security best practice, never hard-code your GitHub token in the code. We will make use of AWS Secrets Manager service to store the GitHub Token and use the CDK APIs to access the token from our code.

Using the Github website, navigate to Settings/Developer Settings/Personal access tokens, create a new token with the following permissions:

• admin:repo_hook
• admin:org_hook
• repo

and don't close the window yet, you will need the token value in the next step.

By default name for this secret is /aws-samples/amazon-ecs-fargate-cdk-v2-cicd/github/personal_access_token.

To change the secret name, make the proper subsititions below,and then specify the optional githubTokenSecretName parameter during the cdk deploy step.

aws configure set region $AWS_REGION
aws secretsmanager create-secret \
 --name /aws-samples/amazon-ecs-fargate-cdk-v2-cicd/github/personal_access_token \
 --secret-string <GITHUB-TOKEN> 

Once the above command is run, check if the secret is stored as expected using below command:

aws secretsmanager get-secret-value \
 --secret-id /aws-samples/amazon-ecs-fargate-cdk-v2-cicd/github/personal_access_token \
 --version-stage AWSCURRENT

It is neccessary to authorize code build to create the hook in Github which will trigger deployments through your Code Pipeline. Replace with your GitHub Personal Access Token in the following snippet and run the following in you development environment.

aws codebuild import-source-credentials \
 --server-type GITHUB \
 --auth-type PERSONAL_ACCESS_TOKEN \
 --token <GITHUB-TOKEN> 

Verify the credential import worked.

aws codebuild list-source-credentials 

Navigate to the cdk-v2 directory of the cloned repo and run the following commands:

cd amazon-ecs-fargate-cdk-v2-cicd/cdk-v2
cdk init
npm install
npm run build
cdk ls
cdk bootstrap aws://$ACCOUNT_ID/$AWS_REGION

Next, you are ready to synthesize and deploy your application:

cdk synth
cdk deploy \
 --parameters githubUserName=<myGithubUserName>

You may be asked to confirm the creation of the roles and authorization before the CloudFormation is executed, for which, you can respond with a “Y”. The infrastructure will take approximately 5-10 minutes time to create, please wait until you see the output of CloudFormation printed on the terminal.

You may also control parameters for your deployment as follows:

cdk deploy \
 --parameters githubUserName=<myGithubUserName>\
 --parameters githubPersonalTokenSecretName="<myGithubPersonalTokenSecretName>" \
 --parameters datadogApiKey="<myDatadogApiKey>" \
 --context stackName="<myStackName>"

When the CloudFormation deployment is complete fetch the URL from the CDK outputs. You can also see this in the AWS Web console.

Initially the app represents the base image which is defined here and added to the ECS Task Definition ./cdk-v2/lib/ecs_cdk-stack.ts:

const container = taskDef.addContainer('flask-app', {
    image: ecs.ContainerImage.fromRegistry("public.ecr.aws/amazonlinux/amazonlinux:2022"),
    memoryLimitMiB: 256,
    cpu: 256,
    logging
});

This is why when first clicking on the app url you will see an error page.

Once the CodePipeline is triggered, CodeBuild will run the set of commands to dockerize the application found in the ./flask-docker-app folder and push it to an Amazon ECR repository. Before deploying it to the ECS infrastructue, it will ask you for manual approval to move to the next stage. Once approved, it will deploy the application into ECS platform, by creating the task definition, service and instantiating the tasks to the desired count. In our case, the default desired count is 1 and thus an instance of flask application will be accessible from Load Balancer as shown above.

The deployment on the ECS initially will take around 5 minutes to ensure the older application task is gracefully drained out and the new task is launched. You would see the ECS service reach a Steady State (shown below), after which the application is accessible. Also notice that the Desired count number is reached.

On accessing the application via ALB, the content will be updated to be below image:

Once code commited and CodePipeline is kicked off, it will deploy the application to the fargate. The successful run of the CI/CD pipeline would look like below:

Once your stack is deployed you are able to quick iterate on code changes, which will automatically build and stage a new version. Once approved, the version is pushed live.

This library is licensed under the MIT-0 License. See the LICENSE file.