Deployment controller

controller.py

#!/usr/bin/env python
import argparse

from kubernetes import client, config
from kubernetes.client.exceptions import NotFoundException

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("replicas", type=int)
    parser.add_argument("--deployment", default="node-placeholder")
    parser.add_argument("-n", "--namespace", default="default")
    args = parser.parse_args()

    # Configs can be set in Configuration class directly or using helper utility
    config.load_kube_config()

    with client.ApiClient() as api_client:
        api_instance = client.AppsV1Api(api_client)
        print("Finding deployment")
        try:
            scale = api_instance.read_namespaced_deployment_scale(
                args.deployment, args.namespace
            )
        except client.NotFoundException:
            raise SystemExit(1)

        print(f"Scaling from {scale.spec.replicas} to {args.replicas} replicas")
        try:
            deployment = api_instance.patch_namespaced_deployment_scale(
                args.deployment, args.namespace, {"spec": {"replicas": args.replicas}}
            )
        except NotFoundException:
            raise SystemExit(1)