OperatorHub for community operators in Kubernetes - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is OperatorHub in Kubernetes?

OperatorHub is a central place where you can find and install Kubernetes Operators, which help automate managing applications and services on your cluster.

beginner

What is a community operator in OperatorHub?

A community operator is an Operator created and maintained by the Kubernetes community, not by Red Hat or other vendors. It is shared openly for anyone to use.

intermediate

How do you install an Operator from OperatorHub?

You can install an Operator from OperatorHub using the OpenShift Console or by running commands with the Operator Lifecycle Manager (OLM) in your Kubernetes cluster.

beginner

Why use community operators from OperatorHub?

Community operators provide easy access to useful tools and applications that automate tasks in Kubernetes, helping you save time and reduce errors.

intermediate

What is the role of the Operator Lifecycle Manager (OLM) with OperatorHub?

OLM helps manage the installation, updates, and lifecycle of Operators from OperatorHub, making sure they run smoothly on your Kubernetes cluster.

What does OperatorHub provide for Kubernetes users?

A A place to store container images

B A service to deploy virtual machines

C A tool to monitor cluster health

D A catalog of Operators to automate app management

OperatorHub offers a catalog of Operators that help automate managing applications on Kubernetes.

Who typically creates community operators?

A Kubernetes community members

B Only Red Hat employees

C Cloud service providers exclusively

D Hardware manufacturers

Community operators are created by members of the Kubernetes community, not limited to any single company.

Which tool manages Operator installation and updates in Kubernetes?

A Docker

B kubectl

C Operator Lifecycle Manager (OLM)

D Helm

OLM manages the lifecycle of Operators including installation and updates.

How can you access Operators from OperatorHub?

A Through the OpenShift Console or OLM commands

B Only by downloading from GitHub

C Using Docker Hub

D Via Kubernetes Dashboard only

Operators can be installed via the OpenShift Console UI or using OLM commands in Kubernetes.

What is a key benefit of using community operators?

A Replace Kubernetes itself

B Automate tasks and save time managing Kubernetes apps

C Increase cluster hardware capacity

D Manage virtual machines

Community operators automate application management tasks, helping users save time and reduce errors.

Explain what OperatorHub is and why community operators are important.

Think about how Operators help manage apps and who makes community operators.

Describe how the Operator Lifecycle Manager (OLM) works with OperatorHub.

Focus on OLM's role in managing Operators from start to finish.

Practice

1. What is OperatorHub in Kubernetes?

easy

A. A tool to monitor Kubernetes cluster health

B. A marketplace for community-made Kubernetes operators

C. A command to deploy pods automatically

D. A storage solution for Kubernetes volumes

Solution

1. Step 1: Understand the purpose of OperatorHub

   OperatorHub is designed as a marketplace where community developers share Kubernetes operators.

2. Step 2: Compare options with the definition

   Only A marketplace for community-made Kubernetes operators correctly describes OperatorHub as a marketplace for community-made operators.

3. Final Answer:

   A marketplace for community-made Kubernetes operators -> Option B

4. Quick Check:

   OperatorHub = Marketplace for operators [OK]

Hint: Remember: OperatorHub = community operator marketplace [OK]

Common Mistakes:

• Confusing OperatorHub with monitoring tools
• Thinking OperatorHub manages storage
• Assuming OperatorHub deploys pods directly

2. Which command lists available operators from OperatorHub?

easy

A. kubectl show operatorhub

B. kubectl list operators

C. kubectl get packagemanifests

D. kubectl get operators

Solution

1. Step 1: Recall the command to view OperatorHub operators

   The correct command is 'kubectl get packagemanifests' to list available operators.

2. Step 2: Eliminate incorrect commands

   Other options are not valid kubectl commands for this purpose.

3. Final Answer:

   kubectl get packagemanifests -> Option C

4. Quick Check:

   List operators = kubectl get packagemanifests [OK]

Hint: Use 'kubectl get packagemanifests' to list operators [OK]

Common Mistakes:

• Using 'kubectl get operators' which is invalid
• Trying 'kubectl list operators' which does not exist
• Confusing with 'kubectl show operatorhub'

3. What happens when you create a Subscription resource pointing to an OperatorHub operator?

medium

A. The cluster restarts immediately

B. The operator is listed but not installed

C. The operator is removed from the cluster

D. The operator is installed and updates are managed automatically

Solution

1. Step 1: Understand Subscription resource role

   Creating a Subscription tells Kubernetes to install the operator and manage updates.

2. Step 2: Analyze each option

   Only The operator is installed and updates are managed automatically correctly describes installation and update management. Others describe unrelated or incorrect effects.

3. Final Answer:

   The operator is installed and updates are managed automatically -> Option D

4. Quick Check:

   Subscription = install + auto-update operator [OK]

Hint: Subscription resource installs and updates operators [OK]

Common Mistakes:

• Thinking Subscription only lists operators
• Assuming Subscription removes operators
• Believing Subscription causes cluster restart

4. You tried to install an operator by creating a Subscription but it did not install. What is a likely cause?

medium

A. The Subscription resource is missing the correct channel or package name

B. The Kubernetes cluster is offline

C. OperatorHub is not installed on the cluster

D. You used 'kubectl get packagemanifests' instead of 'kubectl apply'

Solution

1. Step 1: Check Subscription resource correctness

   If the Subscription lacks the right channel or package name, the operator won't install.

2. Step 2: Evaluate other options

   Cluster offline would prevent all commands; OperatorHub is a service, not installed; wrong command usage is unrelated to Subscription creation.

3. Final Answer:

   The Subscription resource is missing the correct channel or package name -> Option A

4. Quick Check:

   Subscription details must be correct to install operator [OK]

Hint: Check Subscription fields: channel and package name [OK]

Common Mistakes:

• Assuming OperatorHub must be installed separately
• Confusing command usage with resource correctness
• Ignoring Subscription spec details

5. You want to install a community operator from OperatorHub that requires a specific namespace and approval strategy. How do you ensure this during installation?

hard

A. Create a Subscription with 'installPlanApproval' set to 'Manual' and specify the target namespace

B. Run 'kubectl install operator --namespace target' directly

C. Modify the OperatorHub source code to add namespace and approval

D. Use 'kubectl get packagemanifests' with flags for namespace and approval

Solution

1. Step 1: Understand Subscription customization

   Subscription resource supports 'installPlanApproval' to control approval and allows specifying target namespace.

2. Step 2: Evaluate other options

   Direct kubectl install command does not exist; modifying OperatorHub source is unnecessary; 'kubectl get packagemanifests' only lists operators.

3. Final Answer:

   Create a Subscription with 'installPlanApproval' set to 'Manual' and specify the target namespace -> Option A

4. Quick Check:

   Subscription controls approval and namespace settings [OK]

Hint: Set 'installPlanApproval' and namespace in Subscription YAML [OK]

Common Mistakes:

• Trying to install operators with non-existent kubectl commands
• Editing OperatorHub code instead of Subscription
• Using 'kubectl get' commands to install