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Get Master Information

 

Ssh into the master node with ssh cluster1-master1. Check how the master components kubelet, kube-apiserver, kube-scheduler, kube-controller-manager and etcd are started/installed on the master node. Also find out the name of the DNS application and how it's started/installed on the master node.

Write your findings into file /opt/course/8/master-components.txt. The file should be structured like:

Choices of [TYPE] are: not-installed, process, static-pod, pod

 

Answer:

We could start by finding processes of the requested components, especially the kubelet at first:

We can see which components are controlled via systemd looking at /etc/systemd/system directory:

This shows kubelet is controlled via systemd, but no other service named kube nor etcd. It seems that this cluster has been setup using kubeadm, so we check in the default manifests directory:

(The kubelet could also have a different manifests directory specified via parameter --pod-manifest-path in it's systemd startup config)

This means the main 4 master services are setup as static Pods. There also seems to be a second scheduler kube-scheduler-special existing.

Actually, let's check all Pods running on in the kube-system Namespace on the master node:

There we see the 5 static pods, with -cluster1-master1 as suffix.

We also see that the dns application seems to be coredns, but how is it controlled?

Seems like coredns is controlled via a Deployment. We combine our findings in the requested file:

You should be comfortable investigating a running cluster, know different methods on how a cluster and its services can be setup and be able to troubleshoot and find error sources.


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