node-external-ip-controller/node_external_ip_controller.py

from kubernetes import client, config, watch
import os

# Load in-cluster config
config.load_incluster_config()

# Set up Kubernetes API client
v1 = client.CoreV1Api()

# Configuration
SERVICE_NAME = "traefik"
NAMESPACE = "kube-system"
ANNOTATION_KEY = "kube-vip.io/loadbalancerIPs"
NODE_LABEL = "svccontroller.k3s.cattle.io/enablelb=true"


def update_service_annotation(external_ip):
    # Get the current service object
    service = v1.read_namespaced_service(SERVICE_NAME, NAMESPACE)

    # Check if the annotation needs to be updated
    current_annotation = service.metadata.annotations.get(ANNOTATION_KEY)
    if current_annotation != external_ip:
        # Update the annotation
        body = {"metadata": {"annotations": {ANNOTATION_KEY: external_ip}}}
        v1.patch_namespaced_service(SERVICE_NAME, NAMESPACE, body)
        print(f"Updated service {SERVICE_NAME} with new external IP: {external_ip}")


def main():
    w = watch.Watch()
    while True:
        try:
            for event in w.stream(
                v1.list_node, label_selector=NODE_LABEL, _request_timeout=300
            ):
                node = event["object"]
                node_name = node.metadata.name

                # Extract the external IP if it exists
                external_ip = None
                for address in node.status.addresses:
                    if address.type == "ExternalIP" and is_gateway == True:
                        external_ip = address.address
                        break

                if external_ip:
                    print(f"Detected external IP {external_ip} for node {node_name}")
                    update_service_annotation(external_ip)

        except client.exceptions.ApiException as e:
            print(f"API Exception: {e}")
            time.sleep(5)  # Wait before retrying

        except Exception as e:
            print(f"Unexpected error: {e}")
            time.sleep(5)


if __name__ == "__main__":
    main()