How to re-connect to Amazon kubernetes cluster after stopping & starting instances?

Question

I create a cluster for trying out kubernetes using cluster/kube-up.sh in Amazon EC2. Then I stop it to save money when not using it. Next time I start the master & minion instances in amazon, *~/.kube/config has old IP-s for the cluster master as EC2 assigns new public IP to the instances.

Currently I havent found way to provide Elastic IP-s to cluster/kube-up.sh so that consistent IP-s between stopping & starting instances would be set in place. Also the certificate in ~/.kube/config for the old IP so manually changing IP doesn't work either:

Running: ./cluster/../cluster/aws/../../cluster/../_output/dockerized/bin/darwin/amd64/kubectl get pods --context=aws_kubernetes Error: Get https://52.24.72.124/api/v1beta1/pods?namespace=default: x509: certificate is valid for 54.149.120.248, not 52.24.72.124

How to make kubectl make queries against the same kubernetes master on a running on different IP after its restart?

Answer 1

If the only thing that has changed about your cluster is the IP address of the master, you can manually modify the master location by editing the file ~/.kube/config (look for the line that says "server" with an IP address).

This use case (pausing/resuming a cluster) isn't something that we commonly test for so you may encounter other issues once your cluster is back up and running. If you do, please file an issue on the GitHub repository.

Answer 2

I'm not sure which version of Kubernetes you were using but in v1.0.6 you can pass MASTER_RESERVED_IP environment variable to kube-up.sh to assign a given Elastic IP to Kubernetes Master Node.

You can check all the available options for kube-up.sh in config-default.sh file for AWS in Kubernetes repository.