CDK Python - Kubernetes The (real) Hard Way on AWS!
This little project creates the infrastructure in CDK Python for my blog post Kubernetes The (real) Hard Way on AWS.
Terraform code available
🔗 HERE
You can practice creating a multi node K8s Cluster yourself for training purposes or CKA exam preparation.
Requirements
- Existing AWS EC2 Key Pair
- Existing AWS Route53 Public Hosted Zone
- aws-cli Profile
- AWS CDK (
npm install -g cdk) - Python3
Features
Default values - you can adapt all of them to your needs
- AWS CDK Python
- 1x VPC, 3x Public Subnets, 3x Private Subnets, Route Tables, Routes
- 3x Worker Nodes
- 3x Master Nodes
- 3x Etcd Nodes
- 1x Bastion Host
- Route53 Records for internal & external IPv4 addresses
- 1x Public LoadBalancer for Master Nodes (external kubectl access)
- 1x Private LoadBalancer for Master Nodes (fronting kube-apiservers)
- 1x Public LoadBalancer for Bation Host (AutoScalingGroup)
- Gets most recent Ubuntu AMI for all regions (via Boto3)
- Install awscli, cfssl, cfssl_json via UserData
- Allows external access from workstation IPv4 address only (to Bastion & MasterPublicLB)
Variables
| Name | Description | Type | Default |
|---|---|---|---|
| aws_account | AWS account ID to deploy infrastructure | string | '' |
| aws_region | AWS region | string | 'us-east-1' |
| bastion_desired_capacity | Bastion ASG desired nodes | int | 1 |
| bastion_instance_type | Bastion EC2 instance type | string | 't3a.small' |
| bastion_min_capacity | Bastion ASG min. nodes | int | 1 |
| bastion_max_capacity | Bastion ASG max. nodes | int | 1 |
| etcd_desired_capacity | etcd ASG desired nodes | int | 3 |
| etcd_instance_type | etcd EC2 instance type | string | 't3a.small' |
| etcd_min_capacity | etcd ASG min. nodes | int | 3 |
| etcd_max_capacity | etcd ASG max. nodes | int | 3 |
| master_desired_capacity | K8s-Master ASG desired nodes | int | 3 |
| master_instance_type | K8s-Master EC2 instance type | string | 't3a.small' |
| master_min_capacity | K8s-Master ASG min. nodes | int | 3 |
| master_max_capacity | K8s-Master ASG max. nodes | int | 3 |
| worker_desired_capacity | K8s-Worker ASG desired nodes | int | 3 |
| worker_instance_type | K8s-Worker EC2 instance type | string | 't3a.small' |
| worker_min_capacity | K8s-Worker ASG min. nodes | int | 3 |
| worker_max_capacity | K8s-Worker ASG max. nodes | int | 3 |
| ssh_key_pair | AWS EC2 Key Pair name | string | '' |
| pod_cidr | Pod CIDR network first octets (for POD_CIDR envvar) |
string | '10.200' |
| tag_owner | Owner Tag for all resources | string | 'napo.io' |
| tag_project | Project Tag for all resources | string | 'k8s-the-real-hard-way-aws' |
| vpc_cidr | AWS VPC network CIDR | string | '10.5.0.0/16' |
| zone_fqdn | AWS Route53 Hosted Zone name | string | '' |
CDK Python Tutorial
The cdk.json file tells the CDK Toolkit how to execute your app.
This project is set up like a standard Python project. The initialization
process also creates a virtualenv within this project, stored under the .env
directory. To create the virtualenv it assumes that there is a python3
(or python for Windows) executable in your path with access to the venv
package. If for any reason the automatic creation of the virtualenv fails,
you can create the virtualenv manually.
To manually create a virtualenv on MacOS and Linux:
$ python3 -m venv .env
After the init process completes and the virtualenv is created, you can use the following step to activate your virtualenv.
$ source .env/bin/activate
If you are a Windows platform, you would activate the virtualenv like this:
% .env\Scripts\activate.bat
Once the virtualenv is activated, you can install the required dependencies.
$ pip install -r requirements.txt
At this point you can now synthesize the CloudFormation template for this code.
$ cdk synth
To add additional dependencies, for example other CDK libraries, just add
them to your setup.py file and rerun the pip install -r requirements.txt
command.
Useful commands
cdk lslist all stacks in the appcdk synthemits the synthesized CloudFormation templatecdk deploydeploy this stack to your default AWS account/regioncdk diffcompare deployed stack with current statecdk docsopen CDK documentation
Enjoy!