Metrics Server installation in Kubernetes - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to install Metrics Server using kubectl.

Kubernetes

kubectl apply -f [1]

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

Ahttps://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml

Bmetrics-server.yaml

Cdeployment.yaml

Dservice.yaml

Attempts:

3 left

💡 Hint

Common Mistakes

Using a local file name instead of the official URL.

Applying only service.yaml or deployment.yaml which are incomplete manifests.

The correct command applies the official Metrics Server components manifest from the GitHub release URL.

2fill in blank

medium

Complete the kubectl command to check if Metrics Server pods are running in the kube-system namespace.

Kubernetes

kubectl get pods -n [1]

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

Adefault

Bmonitoring

Cmetrics

Dkube-system

Attempts:

3 left

💡 Hint

Common Mistakes

Checking pods in the default namespace where Metrics Server is not deployed.

Using a non-existent namespace like 'metrics' or 'monitoring'.

Metrics Server runs in the kube-system namespace, so you check pods there.

3fill in blank

hard

Fix the error in the Metrics Server deployment by completing the args to allow insecure TLS communication.

Kubernetes

- --kubelet-insecure-tls=[1]

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

Atrue

Bfalse

Cyes

Dno

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'false' disables insecure TLS, causing connection errors.

Using 'yes' or 'no' are invalid boolean values for this flag.

Setting --kubelet-insecure-tls=true allows Metrics Server to skip TLS verification when connecting to kubelets.

4fill in blank

hard

Fill both blanks to complete the command that checks Metrics Server API availability.

Kubernetes

kubectl top [1] -n [2]

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

Anodes

Bpods

Ckube-system

Ddefault

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'pods' with 'default' namespace which may not show Metrics Server data.

Mixing nodes with kube-system namespace which is not required.

The command kubectl top nodes -n default checks resource usage of nodes via Metrics Server. The kubectl top nodes command does not require specifying the kube-system namespace because nodes are cluster-wide resources.

5fill in blank

hard

Fill all three blanks to create a label selector command to find Metrics Server pods.

Kubernetes

kubectl get pods -n [1] -l [2]=[3]

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

Akube-system

Bk8s-app

Cmetrics-server

Ddefault

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong namespace like 'default'.

Using incorrect label keys or values.

This command lists pods in the kube-system namespace with label k8s-app=metrics-server, which identifies Metrics Server pods.

Practice

1. What is the primary purpose of the Kubernetes Metrics Server?

easy

A. To schedule pods on specific nodes

B. To collect live CPU and memory usage data from cluster nodes and pods

C. To store persistent data for applications

D. To manage network policies between pods

Solution

1. Step 1: Understand Metrics Server role

   The Metrics Server collects resource usage data like CPU and memory from nodes and pods in the cluster.

2. Step 2: Differentiate from other components

   It does not manage network policies, store data, or schedule pods, which are handled by other Kubernetes components.

3. Final Answer:

   To collect live CPU and memory usage data from cluster nodes and pods -> Option B

4. Quick Check:

   Metrics Server = resource usage data collection [OK]

Hint: Metrics Server = live resource data collector [OK]

Common Mistakes:

• Confusing Metrics Server with network or storage components
• Thinking it schedules pods
• Assuming it stores persistent data

2. Which command correctly installs the Metrics Server in a Kubernetes cluster?

easy

A. kubectl run metrics-server --image=metrics-server:latest

B. kubectl create deployment metrics-server

C. kubectl install metrics-server

D. kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml

Solution

1. Step 1: Identify official installation method

   The Metrics Server is installed by applying the official components.yaml manifest from the Kubernetes SIGs GitHub repository using kubectl apply.

2. Step 2: Check command correctness

   Only kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml uses kubectl apply with the correct URL. Other options use incorrect commands or methods.

3. Final Answer:

   kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml -> Option D

4. Quick Check:

   Install Metrics Server = kubectl apply official manifest [OK]

Hint: Use kubectl apply with official components.yaml URL [OK]

Common Mistakes:

• Using kubectl create or run instead of apply
• Missing the full URL to the manifest
• Trying to install with a non-existent command

3. After installing Metrics Server, what is the expected output of kubectl top nodes?

medium

A. A list showing CPU and memory usage for each node

B. An error saying Metrics Server is not found

C. A list of pods running on each node

D. No output, command does nothing

Solution

1. Step 1: Understand kubectl top nodes command

   This command shows current CPU and memory usage metrics for each node in the cluster, provided Metrics Server is installed and working.

2. Step 2: Identify expected output

   With Metrics Server installed, it returns a table listing nodes with their CPU and memory usage. Errors or empty output indicate installation or connectivity issues.

3. Final Answer:

   A list showing CPU and memory usage for each node -> Option A

4. Quick Check:

   kubectl top nodes = node resource usage list [OK]

Hint: kubectl top nodes shows node CPU/memory usage [OK]

Common Mistakes:

• Expecting pod lists instead of metrics
• Assuming command fails after installation
• Confusing with other kubectl commands

4. You installed Metrics Server but kubectl top pods returns an error. What is the most likely cause?

medium

A. Metrics Server is not running or has permission issues

B. kubectl top pods command is deprecated

C. You need to restart the Kubernetes cluster

D. Pods do not have resource limits set

Solution

1. Step 1: Analyze error cause

   If kubectl top pods fails, it usually means Metrics Server is not running properly or lacks permissions to gather metrics.

2. Step 2: Rule out other options

   The command is not deprecated, cluster restart is rarely needed, and missing resource limits does not cause this error.

3. Final Answer:

   Metrics Server is not running or has permission issues -> Option A

4. Quick Check:

   kubectl top pods error = Metrics Server problem [OK]

Hint: Check Metrics Server pod status and permissions first [OK]

Common Mistakes:

• Assuming kubectl top pods is deprecated
• Restarting cluster unnecessarily
• Thinking resource limits cause command failure

5. You want to install Metrics Server but your cluster nodes use self-signed certificates causing TLS errors. What is the best way to fix this during installation?

hard

A. Disable TLS on all cluster nodes

B. Install Metrics Server without any changes; it will auto-fix TLS

C. Edit the Metrics Server deployment to add --kubelet-insecure-tls argument

D. Use a different monitoring tool that does not require TLS

Solution

1. Step 1: Identify TLS issue cause

   Self-signed certificates cause TLS verification errors when Metrics Server connects to kubelets.

2. Step 2: Apply correct fix

   Adding the --kubelet-insecure-tls flag to Metrics Server deployment disables strict TLS verification, allowing it to work with self-signed certs.

3. Step 3: Rule out unsafe or incorrect options

   Disabling TLS cluster-wide is unsafe, Metrics Server does not auto-fix TLS, and switching tools is unnecessary.

4. Final Answer:

   Edit the Metrics Server deployment to add --kubelet-insecure-tls argument -> Option C

5. Quick Check:

   Self-signed certs fix = add --kubelet-insecure-tls [OK]

Hint: Add --kubelet-insecure-tls flag for self-signed certs [OK]

Common Mistakes:

• Disabling TLS on nodes (unsafe)
• Expecting Metrics Server to auto-fix TLS
• Ignoring TLS errors and proceeding