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Practice Test - OS Upgrades

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Solutions to practice test - OS Upgrades

• Let us explore the environment first. How many nodes do you see in the cluster?

  ``` $ kubectl get nodes ```

• How many applications do you see hosted on the cluster?

  ``` $ kubectl get deploy ```

• Run the command ‘kubectl get pods -o wide’ and get the list of nodes the pods are placed on

  ``` $ kubectl get pods -o wide ```

• Run the command kubectl drain node01 –ignore-daemonsets

  ``` $ kubectl drain node01 --ignore-daemonsets ```

• Run the command ‘kubectl get pods -o wide’ and get the list of nodes the pods are placed on

  ``` $ kubectl get pods -o wide ```

• Run the command kubectl uncordon node01

  ``` $ kubectl uncordon node01 ```

• Run the command kubectl get pods -o wide

  ``` $ kubectl get pods -o wide ```

• Why are there no pods on node01?

  ``` Only when new pods are created they will be scheduled ```

• Use the command kubectl describe node master and look under taint section to check if it has any taints.

  ``` $ kubectl describe node master ```

• Run the command kubectl drain node02 –ignore-daemonsets

  ``` $ kubectl drain node02 --ignore-daemonsets ```

• Check the applications hosted on the node02.

  ``` node02 has a pod not part of a replicaset $ kubectl get pods -o wide ```

• Check the list of pods

  ``` $ kubectl get pods -o wide ```

• What would happen to hr-app if node02 is drained forcefully?

  ``` $ kubectl drain node02 --ignore-daemonsets --force hr-app will be lost forever ```

• Run the command kubectl drain node02 –ignore-daemonsets –force

  ``` $ kubectl drain node02 --ignore-daemonsets --force ```

• Run the command kubectl cordon node03

  ``` $ kubectl cordon node03 ```