High availability cluster setup in Kubernetes - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the number of master nodes in a Kubernetes HA cluster.

Kubernetes

apiVersion: kubeadm.k8s.io/v1beta3
kind: ClusterConfiguration
controlPlaneEndpoint: "loadbalancer.example.com:6443"
controllerManager:
  extraArgs:
    node-monitor-grace-period: "40s"
    node-monitor-period: "5s"
    pod-eviction-timeout: "1m0s"
scheduler:
  extraArgs:
    leader-elect: "true"
---
apiVersion: kubeadm.k8s.io/v1beta3
kind: InitConfiguration
nodeRegistration:
  name: master-1
  kubeletExtraArgs:
    node-labels: "node-role.kubernetes.io/master="
    authorization-mode: AlwaysAllow
---
apiVersion: kubeadm.k8s.io/v1beta3
kind: JoinConfiguration
controlPlane:
  localAPIEndpoint:
    advertiseAddress: "192.168.1.10"
    bindPort: 6443
  [1]: 3

Drag options to blanks, or click blank then click option'

AmasterCount

BreplicaCount

CcontrolPlaneReplicas

Dreplicas

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'replicaCount' which is common in Helm charts but not in kubeadm config.

Using 'masterCount' which is not a valid kubeadm key.

The correct key to specify the number of master nodes in kubeadm HA setup is 'replicas'.

2fill in blank

medium

Complete the command to initialize the Kubernetes control plane with high availability.

Kubernetes

kubeadm init --control-plane-endpoint [1] --upload-certs

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A192.168.1.10:6443

Bloadbalancer.example.com:6443

Cmaster-1:6443

Dlocalhost:6443

Attempts:

3 left

💡 Hint

Common Mistakes

Using a single master node IP instead of the load balancer.

Using localhost which is not accessible externally.

The control plane endpoint should be the load balancer address that fronts the master nodes.

3fill in blank

hard

Fix the error in the kubeadm join command to add a new control plane node.

Kubernetes

kubeadm join loadbalancer.example.com:6443 --token [1] --discovery-token-ca-cert-hash sha256:abcdef1234567890 --control-plane --certificate-key abcdef1234567890

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A0123456789abcdef

Babcdef

Cabcdef.0123456789abcdef

Dtoken1234

Attempts:

3 left

💡 Hint

Common Mistakes

Using incomplete or partial token strings.

Omitting the dot separator in the token.

The token must be in the correct format with a dot separating two parts, e.g., 'abcdef.0123456789abcdef'.

4fill in blank

hard

Fill both blanks to create a Kubernetes Service manifest for the HA control plane load balancer.

Kubernetes

apiVersion: v1
kind: Service
metadata:
  name: kubernetes
  namespace: default
spec:
  type: [1]
  ports:
  - port: 6443
    targetPort: 6443
  selector:
    [2]: master-node

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ALoadBalancer

BClusterIP

Capp

Drole

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'ClusterIP' which does not expose the service externally.

Using incorrect selector keys like 'app' when 'role' is expected.

The service type for external load balancing is 'LoadBalancer', and the selector key is commonly 'role' to select master nodes.

5fill in blank

hard

Fill all three blanks to define a Pod Anti-Affinity rule to spread master nodes across failure domains.

Kubernetes

affinity:
  podAntiAffinity:
    requiredDuringSchedulingIgnoredDuringExecution:
    - labelSelector:
        matchExpressions:
        - key: [1]
          operator: In
          values:
          - master
      topologyKey: [2]
  nodeAffinity:
    requiredDuringSchedulingIgnoredDuringExecution:
      nodeSelectorTerms:
      - matchExpressions:
        - key: [3]
          operator: In
          values:
          - zone-a
          - zone-b

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Akubernetes.io/role

Bkubernetes.io/hostname

Cfailure-domain.beta.kubernetes.io/zone

Dnode-role.kubernetes.io/master

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect label keys for roles or topology.

Confusing node labels with pod labels.

The podAntiAffinity key is 'node-role.kubernetes.io/master', topologyKey is 'kubernetes.io/hostname' to spread pods across nodes, and nodeAffinity key is the zone label 'failure-domain.beta.kubernetes.io/zone'.