CKA Question #17: Real Exam Question with Answer & Explanation

Question

For this item, you will have to ssh to the nodes ik8s-master-0 and ik8s-node-0 and complete all tasks on these nodes. Ensure that you return to the base node (hostname: node-1) when you have completed this item. Context As an administrator of a small development team, you have been asked to set up a Kubernetes cluster to test the viability of a new application. Task You must use kubeadm to perform this task. Any kubeadm invocations will require the use of the --ignore-preflight-errors=all option. Configure the node ik8s-master-0 as a master node. Join the node ik8s-node-0 to the cluster.

Explanation

This simulation task tests your ability to bootstrap a Kubernetes cluster from scratch using kubeadm, including initializing a control plane (master) node and joining a worker node to it. It mirrors real-world cluster setup procedures that a Kubernetes administrator must know.

Approach. First, SSH into ik8s-master-0 and run 'kubeadm init --ignore-preflight-errors=all' to initialize the control plane; this outputs a 'kubeadm join' command with a token and CA cert hash that you must save. After init completes, configure kubectl access by copying the admin kubeconfig: 'mkdir -p $HOME/.kube && sudo cp /etc/kubernetes/admin.conf $HOME/.kube/config && sudo chown $(id -u):$(id -g) $HOME/.kube/config'. Next, SSH into ik8s-node-0 and run the saved 'kubeadm join <master-ip>:6443 --token <token> --discovery-token-ca-cert-hash sha256:<hash> --ignore-preflight-errors=all' to register the worker node. Finally, return to node-1 (the base node) as instructed, and optionally verify the cluster state with 'kubectl get nodes' from the master.

Concept tested. Kubernetes cluster bootstrapping with kubeadm - specifically: initializing a control plane node (kubeadm init), capturing the join token/command, configuring kubectl credentials post-init, and joining a worker node to the cluster (kubeadm join). The --ignore-preflight-errors=all flag is required in lab/exam environments where resource or system checks would otherwise block initialization.

Reference. https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/

No community discussion yet for this question.