Helm charts concept in Kubernetes - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Helm chart in Kubernetes?

A Helm chart is a package that contains all the files needed to create a Kubernetes application. It helps you install, upgrade, and manage apps easily.

beginner

What are the main parts of a Helm chart?

A Helm chart has templates (YAML files), a Chart.yaml file (metadata), and values.yaml (default settings). These parts work together to define the app and its configuration.

beginner

How does Helm use values.yaml?

values.yaml holds default settings for the app. You can change these values when installing or upgrading to customize the app without changing the templates.

beginner

What command installs a Helm chart into a Kubernetes cluster?

The command is helm install RELEASE_NAME CHART_NAME. It deploys the app using the chart and creates Kubernetes resources.

beginner

Why use Helm charts instead of plain Kubernetes YAML files?

Helm charts let you reuse, share, and manage apps easily. They handle complex setups with templates and values, saving time and reducing errors.

What file in a Helm chart contains the app's metadata?

A templates/deployment.yaml

B values.yaml

C Chart.yaml

D README.md

Chart.yaml holds metadata like the chart name, version, and description.

Which Helm command installs a chart into your Kubernetes cluster?

A helm delete

B helm create

C helm update

D helm install

helm install deploys the chart as a release in the cluster.

What is the purpose of the values.yaml file in a Helm chart?

A To store default configuration values

B To define Kubernetes resource templates

C To list Helm chart dependencies

D To describe the chart metadata

values.yaml holds default settings that can be customized during install or upgrade.

How do Helm charts help manage Kubernetes apps?

A By monitoring cluster health

B By providing reusable templates and easy upgrades

C By storing container images

D By replacing Kubernetes entirely

Helm charts use templates and values to simplify app deployment and upgrades.

Which folder in a Helm chart contains Kubernetes resource templates?

A templates

B charts

C config

D bin

The templates folder holds YAML files that define Kubernetes resources.

Explain what a Helm chart is and why it is useful in Kubernetes.

Think about how Helm helps manage complex Kubernetes apps.

Describe the main files and folders inside a Helm chart and their roles.

Consider what each part controls in the app deployment.

Practice

1. What is the primary purpose of a Helm chart in Kubernetes?

easy

A. To replace kubectl commands

B. To monitor Kubernetes cluster health

C. To package and deploy Kubernetes applications easily

D. To create Docker images

Solution

1. Step 1: Understand Helm chart role

   A Helm chart bundles Kubernetes app resources for easy deployment and sharing.

2. Step 2: Compare options

   Options B, C, and D describe other tools or tasks unrelated to Helm charts.

3. Final Answer:

   To package and deploy Kubernetes applications easily -> Option C

4. Quick Check:

   Helm chart = package & deploy app [OK]

Hint: Helm charts bundle apps for easy deployment [OK]

Common Mistakes:

• Confusing Helm with monitoring tools
• Thinking Helm replaces kubectl entirely
• Assuming Helm builds Docker images

2. Which Helm command is used to create a new chart skeleton?

easy

A. helm rollback

B. helm install

C. helm upgrade

D. helm create

Solution

1. Step 1: Identify command purpose

   helm create generates a new chart directory with default files.

2. Step 2: Eliminate other commands

   helm install deploys charts, helm upgrade updates releases, helm rollback reverts upgrades.

3. Final Answer:

   helm create -> Option D

4. Quick Check:

   New chart skeleton = helm create [OK]

Hint: Use helm create to start a chart [OK]

Common Mistakes:

• Using helm install to create charts
• Confusing upgrade with create
• Trying rollback to create charts

3. Given the command helm install myapp ./mychart, what happens?

medium

A. Installs the release 'myapp' using the chart from the local directory './mychart'

B. Creates a new chart named 'myapp' in './mychart'

C. Upgrades the release 'myapp' with './mychart'

D. Rolls back the release 'myapp' to './mychart'

Solution

1. Step 1: Understand helm install syntax

   helm install [release-name] [chart-path] deploys the chart as a release.

2. Step 2: Analyze given command

   Here, 'myapp' is the release name, './mychart' is the chart directory to deploy.

3. Final Answer:

   Installs the release 'myapp' using the chart from the local directory './mychart' -> Option A

4. Quick Check:

   helm install = deploy chart [OK]

Hint: helm install deploys chart as release [OK]

Common Mistakes:

• Thinking install creates charts
• Confusing install with upgrade or rollback
• Misunderstanding release name vs chart path

4. You run helm upgrade myapp ./mychart but get an error: "release: not found". What is the likely cause?

medium

A. The release 'myapp' does not exist yet

B. The chart path './mychart' is invalid

C. You need to use helm install instead of upgrade

D. The Kubernetes cluster is down

Solution

1. Step 1: Understand helm upgrade error

   The error "release: not found" means the named release does not exist in the cluster.

2. Step 2: Identify correct cause

   Since upgrade updates existing releases, trying to upgrade a non-existent release causes this error.

3. Final Answer:

   The release 'myapp' does not exist yet -> Option A

4. Quick Check:

   Upgrade needs existing release [OK]

Hint: Upgrade fails if release not installed yet [OK]

Common Mistakes:

• Assuming chart path error causes this message
• Using upgrade instead of install for new release
• Blaming cluster status without checking release

5. You want to deploy a Helm chart and be able to easily revert to the previous version if needed. Which Helm commands should you use in order?

hard

A. helm create, helm install, helm rollback

B. helm install, helm upgrade, helm rollback

C. helm create, helm upgrade, helm rollback

D. helm install, helm create, helm rollback

Solution

1. Step 1: Understand deployment and version control

   First, use helm install to deploy the initial release.

2. Step 2: Manage updates and rollback

   Use helm upgrade to update the release, and helm rollback to revert if needed.

3. Step 3: Eliminate incorrect sequences

   helm create is for making charts, not deployment steps. It should not be in the deploy/rollback sequence.

4. Final Answer:

   helm install, helm upgrade, helm rollback -> Option B

5. Quick Check:

   Install -> Upgrade -> Rollback = C [OK]

Hint: Install first, then upgrade, rollback if needed [OK]

Common Mistakes:

• Using helm create in deployment sequence
• Skipping install before upgrade
• Confusing rollback with create