Step 1: Create the Pod and Service
To begin, create a Pod named check-ip in the default namespace and expose it via a ClusterIP Service:
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kubectl run check-ip --image=httpd:2.4.41-alpine --restart=Never kubectl expose pod check-ip --name=check-ip-service --port=80 |
Step 2: Retrieve the IP of the Service
Retrieve the ClusterIP of the check-ip-service to check its initial configuration:
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kubectl get svc check-ip-service |
Step 3: Change the Service CIDR
To change the Service CIDR for the cluster, follow these steps:
SSH into the control plane node:
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ssh cluster2-controlplane1 |
Edit the kube-apiserver manifest to update the --service-cluster-ip-range parameter:
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vim /etc/kubernetes/manifests/kube-apiserver.yaml |
Change the line to:
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--service-cluster-ip-range=11.96.0.0/12 |
Save the file and wait for the kube-apiserver to restart.
Similarly, update the kube-controller-manager manifest:
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vim /etc/kubernetes/manifests/kube-controller-manager.yaml |
Change the line to:
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--service-cluster-ip-range=11.96.0.0/12 |
Save the file and wait for the kube-controller-manager to restart.
Step 4: Verify the Change
Create a second Service pointing to the same Pod:
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kubectl expose pod check-ip --name=check-ip-service2 --port=80 |
Verify the IP address of both services:
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kubectl get svc check-ip-service check-ip-service2 |
Expected Results
Service 1 (check-ip-service) should retain its original IP.
Service 2 (check-ip-service2) should have an IP from the new CIDR range (11.96.0.0/12).
Conclusion
This process demonstrates how to change the Service CIDR in a Kubernetes cluster and verify the changes by creating new services to see the updated IP ranges.