Cluster Architecture, Installation, and Configuration Flashcards

When upgrading a cluster with kubeadm, what is the correct order of operations?

Answer: Upgrade control plane first, then workers

You must upgrade the control plane components first with kubeadm upgrade apply, then upgrade each worker node individually.

Which command drains a node and marks it as unschedulable before maintenance?

Answer: kubectl drain

kubectl drain evicts all pods from a node and marks it unschedulable, making it safe for maintenance.

In a high-availability control plane, how does the kube-scheduler ensure only one instance is active at a time?

Answer: Leader election using a lease object

The kube-scheduler uses leader election via a Lease API object in the kube-system namespace so only one scheduler instance is active.

What does the kubelet use to authenticate to the kube-apiserver in a kubeadm cluster?

Answer: A client TLS certificate in /var/lib/kubelet/pki

The kubelet uses a client certificate (in /var/lib/kubelet/pki/kubelet-client-current.pem) generated during node bootstrapping to authenticate to the API server.

Which ConfigMap in the kube-system namespace stores the kubeadm cluster configuration?

Answer: kubeadm-config

kubeadm stores its ClusterConfiguration in the kubeadm-config ConfigMap in the kube-system namespace.

What is the role of the Node Authorizer in Kubernetes?

Answer: Authorizes API calls made by kubelet based on the node's identity

The Node Authorizer is a special-purpose authorization mode that grants kubelets permission to perform API operations for the objects bound to their specific node.

Which kubeadm phase generates the kubeconfig files for cluster administrators?

Answer: kubeadm init phase kubeconfig

kubeadm init phase kubeconfig generates admin.conf, controller-manager.conf, and scheduler.conf kubeconfig files.