AWS CDK - Project Setup and Bootstrapping

This is Chapter 1 of the Infrastructure as Code with AWS CDK series. Two things come before writing any stack code: initialising the CDK project and bootstrapping the AWS account.

Prerequisites

• Python 3.9+
• Node.js 18+ (CDK CLI is a Node package)
• AWS CLI v2 configured with valid credentials - see Connect to AWS SSO and SSH into EC2 Instance
• An AWS account with permissions to create IAM roles, S3 buckets, and CloudFormation stacks

Install the CDK CLI globally:

npm install -g aws-cdk
cdk --version

Initialise project

Create a new directory and initialise a CDK Python project inside it:

mkdir my-cdk-app && cd my-cdk-app
cdk init app --language python

This scaffolds the project with a virtual environment, a sample stack, and a cdk.json config file.

Activate the virtual environment and install dependencies:

# macOS / Linux
source .venv/bin/activate

# Windows (PowerShell)
.venv\Scripts\activate.ps1

pip install -r requirements.txt

Directory structure

After initialisation the project looks like this:

my-cdk-app/
├── app.py                  # CDK app entry point
├── cdk.json                # CDK config and context
├── requirements.txt        # Python dependencies
├── requirements-dev.txt    # Dev dependencies (e.g. pytest)
├── .venv/                  # Python virtual environment
└── my_cdk_app/
    ├── __init__.py
    └── my_cdk_app_stack.py # Default stack

app.py is where the CDK app is defined and stacks are instantiated. my_cdk_app_stack.py is where resources are defined. The folder and class names match the project name passed to cdk init.

Bootstrap AWS account

CDK needs a one-time setup in each AWS account and region it deploys to. Bootstrapping creates an S3 bucket (for assets) and IAM roles (for deployments) in the account:

cdk bootstrap aws://123456789012/us-east-1

Replace 123456789012 with your account ID and us-east-1 with your target region. If credentials are already configured via AWS CLI or SSO, the account ID can be omitted:

cdk bootstrap

This only needs to run once per account/region combination. Re-running it is safe - it updates the bootstrap stack if needed.

Synth and deploy

CDK compiles Python into CloudFormation before deploying. Run synth to see the generated CloudFormation template:

cdk synth

This outputs a CloudFormation template to cdk.out/. Use it to verify what CDK will create before deploying.

Deploy the stack:

cdk deploy

CDK shows a diff of changes and prompts for confirmation before creating or modifying any IAM resources.

Verify

After deploying, the stack appears in CloudFormation in the AWS console. Check:

• CloudFormation > Stacks > MyCdkAppStack - status should be CREATE_COMPLETE
• S3 > Buckets - the CDK bootstrap bucket should be visible (cdk-hnb659fds-assets-...)

To tear down the stack:

cdk destroy

Notes