Installing charts in Kubernetes - Quick Revision & Summary

Recall & Review

beginner

What is a Helm chart in Kubernetes?

A Helm chart is a package that contains all the resource definitions needed to run an application or service inside a Kubernetes cluster.

beginner

Which command installs a Helm chart into a Kubernetes cluster?

The command helm install <release-name> <chart-name> installs a Helm chart into the cluster.

intermediate

What does the --namespace flag do when installing a Helm chart?

The --namespace flag specifies the Kubernetes namespace where the chart resources will be installed.

intermediate

How do you update a Helm chart after it is installed?

Use helm upgrade <release-name> <chart-name> to update an installed Helm chart with new changes.

beginner

What is the purpose of the helm repo add command?

It adds a remote Helm chart repository so you can install charts from that source.

Which command installs a Helm chart named 'nginx' with release name 'webserver'?

A helm install webserver nginx

B kubectl install nginx webserver

C helm create webserver nginx

D kubectl apply -f nginx

The correct syntax to install a Helm chart is 'helm install '.

What does the helm repo update command do?

A Upgrades an installed chart

B Updates the local cache of chart repositories

C Installs a new chart

D Deletes a chart repository

It refreshes the local list of charts available from added repositories.

How do you specify a namespace when installing a Helm chart?

A helm install <release> <chart> --namespace <name>

B kubectl install <chart> --namespace <name>

C helm create <namespace>

D helm upgrade <release> --namespace <name>

The '--namespace' flag is used with 'helm install' to set the target namespace.

If you want to change the configuration of an installed chart, which command should you use?

A helm delete

B helm install

C helm upgrade

D kubectl apply

Use 'helm upgrade' to apply configuration changes to an existing release.

What is the first step before installing charts from a new Helm repository?

A Run 'kubectl create namespace'

B Run 'helm install' directly

C Delete existing charts

D Add the repository with 'helm repo add'

You must add the repository to Helm before installing charts from it.

Explain the steps to install a Helm chart into a Kubernetes cluster.

Think about preparing the source and then running the install command.

Describe how you would update an existing Helm chart installation with new settings.

Upgrading is like reinstalling but keeps the release name.

Practice

1. What is the primary purpose of using helm install in Kubernetes?

easy

A. To deploy an application packaged as a Helm chart

B. To delete a Kubernetes namespace

C. To update the Kubernetes cluster version

D. To create a new Kubernetes node

Solution

1. Step 1: Understand Helm's role

   Helm packages Kubernetes apps into charts for easy deployment.

2. Step 2: Purpose of helm install

   This command deploys the packaged app (chart) into the cluster.

3. Final Answer:

   To deploy an application packaged as a Helm chart -> Option A

4. Quick Check:

   Helm install = deploy app [OK]

Hint: Helm install means deploy app from chart [OK]

Common Mistakes:

• Confusing install with delete or update commands
• Thinking helm install creates nodes
• Assuming helm install manages cluster versions

2. Which of the following is the correct syntax to install a Helm chart named nginx with release name myweb?

easy

A. helm install nginx myweb

B. helm create myweb nginx

C. helm install myweb nginx

D. helm deploy myweb nginx

Solution

1. Step 1: Recall Helm install syntax

   The correct syntax is helm install [release-name] [chart-name].

2. Step 2: Match syntax to options

   helm install myweb nginx uses helm install myweb nginx, which matches the syntax.

3. Final Answer:

   helm install myweb nginx -> Option C

4. Quick Check:

   helm install release chart = helm install myweb nginx [OK]

Hint: Remember: helm install release-name chart-name [OK]

Common Mistakes:

• Swapping release name and chart name order
• Using helm create or helm deploy instead of install
• Omitting release name

3. What will be the output of the command helm install myapp bitnami/nginx --namespace web if the namespace web does not exist?

medium

A. Helm will prompt to create the namespace interactively

B. Helm will create the namespace web and install the chart

C. Helm will install the chart in the default namespace

D. Installation will fail with an error about missing namespace

Solution

1. Step 1: Understand namespace behavior

   Helm does not create namespaces automatically during install.

2. Step 2: Effect of missing namespace

   If the specified namespace web does not exist, Helm will error out.

3. Final Answer:

   Installation will fail with an error about missing namespace -> Option D

4. Quick Check:

   Missing namespace causes install error [OK]

Hint: Helm won't create namespaces automatically [OK]

Common Mistakes:

• Assuming Helm auto-creates namespaces
• Expecting install to default namespace silently
• Thinking Helm prompts for namespace creation

4. You run helm install myapp nginx --set replicaCount=3 but the app still runs with 1 replica. What is the likely cause?

medium

A. You must specify the namespace with --namespace

B. The chart does not support the replicaCount parameter

C. The --set flag syntax is incorrect

D. The Helm client version is outdated

Solution

1. Step 1: Check parameter support

   Not all charts support all parameters; replicaCount must be defined in the chart's values.

2. Step 2: Effect of unsupported parameter

   If unsupported, setting replicaCount has no effect, so default 1 replica remains.

3. Final Answer:

   The chart does not support the replicaCount parameter -> Option B

4. Quick Check:

   Unsupported param means no effect [OK]

Hint: Check if chart supports your --set keys [OK]

Common Mistakes:

• Assuming all charts accept replicaCount
• Thinking namespace affects replica count
• Believing --set syntax is always wrong
• Blaming Helm version without checking chart

5. You want to install a Helm chart myapp with a custom image tag v2.0 and in namespace production. Which command correctly does this in one step?

hard

A. helm install myapp ./myapp-chart --set image.tag=v2.0 --namespace production

B. helm install ./myapp-chart myapp --set image.tag=v2.0 --namespace production

C. helm install myapp ./myapp-chart --image.tag=v2.0 --namespace production

D. helm install myapp ./myapp-chart --set image=v2.0 --namespace production

Solution

1. Step 1: Confirm Helm install syntax

   The syntax is helm install [release-name] [chart-path] [flags].

2. Step 2: Correct use of --set and namespace

   Use --set image.tag=v2.0 to override image tag and --namespace production to specify namespace.

3. Final Answer:

   helm install myapp ./myapp-chart --set image.tag=v2.0 --namespace production -> Option A

4. Quick Check:

   Release, chart, --set key=value, --namespace [OK]

Hint: Use --set key=value and --namespace together [OK]

Common Mistakes:

• Swapping release name and chart path
• Using --image.tag instead of --set
• Setting wrong key like image=v2.0
• Omitting namespace flag