CDK8S Deployment CLI

A CLI for deploying Python cdk8s applications.

This is a work-in-progress project with no promise of continued support or development. This is not sutable for production applications.

Rationale

cdk8s is a great tool for defining Kubernetes resources using code and rendering them into a Kubernetes manifest, however there is a gap in the tooling for deploying cdk8s applications. It can be done a number of ways, such as:

1. Rendering the manifest and applying it with kubectl
2. Using the existing cdk8s cli to generate a Helm chart and then applying it with helm
3. Utilising integrations with other IaC tools such as the AWS CDK or Terraform

This project aims to fill that gap by providing a CLI for deploying cdk8s applications directly using the kubernetes Python client.

Usage

# Import the dependencies
from cdk8s_cli.cdk8s_cli import cdk8s_cli
from cdk8s import App, Chart

class ApplicationChart(Chart):
  # Define cdk8s chart here
  ...

# Construct your Apps and charts as you normally would:
app = App()
ApplicationChart(app, "chart-name")

# Then call the CLI with:
cdk8s_cli(app, name="my-app")

That's it! You can now run your application with the desired flags

> python3 my-app.py apply
Resources synthed to /Users/exampleuser/project/my-project/dist
Deploy resources? [y/N]: y
Resource simple-cdk8s-chart-c81aeaa7                    applied.
Resource simple-cdk8s-chart-deployment-c83ea641         applied in namespace simple-cdk8s-chart-c81aeaa7.
Resource simple-cdk8s-chart-deployment-service-c8f17013 applied in namespace simple-cdk8s-chart-c81aeaa7.
Apply complete

Example CLI Usage

Synth all apps

python3 main.py synth

Deploy all apps

python3 main.py deploy

Deploy selected apps

python3 main.py deploy --apps dev prod

Options

positional arguments:
  {synth,apply,list}    the action to perform. synth will synth the resources
                        to the output directory. apply will apply the
                        resources to the Kubernetes cluster

options:
  -h, --help            show this help message and exit
  --apps APPS [APPS ...]
                        the apps to apply. Defaults to all apps. If supplied,
                        apps not in this list will be skipped
  --kube-context KUBE_CONTEXT
                        the Kubernetes context to use. Defaults to minikube
  --kube-config-file KUBE_CONFIG_FILE
                        the path to a kubeconfig file
  --verbose             enable verbose output
  --unattended          enable unattended mode. This will not prompt for
                        confirmation before applying
  --debug               enable debug mode. This will print debug information
  --validate            experimental feature. Will enable validation mode.
                        This will wait for resources to report ready before
                        exiting
  --validate-timeout-minutes VALIDATE_TIMEOUT_MINUTES
                        the number of minutes to wait for resources to report
                        ready before timing out. Needs --validate to be set

Development

This project is built using:

• Poetry as the package manager
• Ruff for formatting and linting

Features to be implemented

• Unit tests
• End-to-end tests
  • Use the example projects for this
• Complete documentation
• Improve customisation
  • More inputs, more flexability
• Diff functionality
  • Similar to kubectl diff
• Destroy functionality
  • Similar to kubectl delete
• List functionality
  • List all resources in an app
  • Useful, hierarchical view

Examples

Examples can be run using poetry run python3 examples/<example>/<example>.py synth

Simple Example

Link

A very basic example containing a chart with a few simple resources in a single file deployed as a single stage.

Complex Example

Link

A more complex example with multiple charts and multiple stages.

Jobs Example

Link

An example job runner that executes Python scripts from a directory of scripts as jobs.