To create a service in Kubernetes that exposes individual pods through a NodePort that corresponds with the node they are scheduled on, you can follow these steps:
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
labels:
app: nginx
spec:
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
ports:
- containerPort: 80
apiVersion: v1
kind: Service
metadata:
name: nginx-service
spec:
selector:
app: nginx
ports:
- protocol: TCP
port: 80
targetPort: 80
type: NodePort
from kubernetes import client, config
# Load Kubernetes config
config.load_kube_config()
# Create Kubernetes API client
api = client.CoreV1Api()
# Get all nodes and their addresses
nodes = api.list_node()
node_addrs = {}
for node in nodes.items:
node_addrs[node.metadata.name] = node.status.addresses[0].address
# Get all pods and their node name
pods = api.list_pod_for_all_namespaces()
pod_nodes = {}
for pod in pods.items:
pod_nodes[pod.metadata.name] = pod.spec.node_name
# Map each pod to the corresponding node port
for pod_name, node_name in pod_nodes.items():
node_addr = node_addrs[node_name]
node_port = int(pod_name[-5:]) + 30000 # calculate node port from pod name
endpoints = [client.V1EndpointAddress(ip=node_addr, target_ref=client.V1ObjectReference(kind='Pod', name=pod_name))]
subset = client.V1EndpointSubset(addresses=endpoints)
api.patch_namespaced_endpoints(name='nginx-service', namespace='default', body=client.V1Endpoints(subsets=[subset]), subresource='')
This script retrieves all the nodes in the cluster and their addresses. It then retrieves all the pods in the cluster, and for each pod, it retrieves the name of the node on which the pod is scheduled. It then calculates the node port from the last 5 digits of the pod name (assuming the pod name ends with a 5-digit random string), and patches the endpoints of the 'nginx-service' service to map the pod to the correct node IP and port. This will effectively expose each pod through a NodePort that corresponds with the node they are scheduled on.
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Asked: 2023-05-14 01:49:07 +0000
Seen: 10 times
Last updated: May 14 '23