Creating custom namespaces in Kubernetes - Visual Walkthrough

Process Flow - Creating custom namespaces

Write YAML file for Namespace

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Run kubectl apply -f namespace.yaml

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Kubernetes API Server receives request

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Namespace resource created in cluster

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kubectl get namespaces shows new namespace

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Use namespace in pods/deployments

This flow shows how you create a custom namespace by writing a YAML file, applying it with kubectl, and then using it in your cluster.

Execution Sample

Kubernetes

apiVersion: v1
kind: Namespace
metadata:
  name: my-custom-namespace

This YAML defines a new Kubernetes namespace called 'my-custom-namespace'.

Process Table

Step	Command/Action	System Response	Resulting State
1	Create namespace.yaml file with namespace definition	File created locally	namespace.yaml exists with correct content
2	kubectl apply -f namespace.yaml	Namespace 'my-custom-namespace' created	Namespace resource added to cluster
3	kubectl get namespaces	Lists all namespaces including 'my-custom-namespace'	User sees new namespace in list
4	Use namespace in pod/deployment spec	Pods/deployments created in 'my-custom-namespace'	Resources scoped to custom namespace
5	kubectl delete namespace my-custom-namespace	Namespace and all resources inside deleted	Namespace removed from cluster

💡 Namespace creation completes after kubectl apply; visible in namespace list and usable for resource scoping.

Status Tracker

Variable	Start	After Step 2	After Step 3	Final
namespace.yaml	Not created	Created with namespace definition	Unchanged	Unchanged
Cluster Namespaces	Default namespaces only	Includes 'my-custom-namespace'	Includes 'my-custom-namespace'	Depends on deletion
Resources in 'my-custom-namespace'	None	None	None	Created after deployment

Key Moments - 3 Insights

Why doesn't the namespace appear immediately after creating the YAML file?

Creating the YAML file only saves the definition locally. The namespace appears in the cluster only after running 'kubectl apply -f namespace.yaml' as shown in execution_table step 2.

Can I create pods in a namespace before it exists?

No, pods must be created after the namespace exists in the cluster. The namespace resource must be applied first (step 2), then pods can be created inside it (step 4).

What happens if I delete a namespace?

Deleting a namespace removes it and all resources inside it from the cluster, as shown in step 5 of the execution_table.

Visual Quiz - 3 Questions

Look at the execution table, what command creates the namespace resource in the cluster?

A kubectl get namespaces

B kubectl apply -f namespace.yaml

C kubectl delete namespace my-custom-namespace

D Creating the YAML file

💡 Hint

Check step 2 in the execution_table where the namespace is created.

At which step does the new namespace become visible when listing namespaces?

A Step 3

B Step 2

C Step 1

D Step 4

💡 Hint

Look at the system response in step 3 of the execution_table.

If you delete the namespace, what happens to the resources inside it?

A They remain in the cluster

B They move to the default namespace

C They are deleted along with the namespace

D They become inactive but stay allocated

💡 Hint

Refer to step 5 in the execution_table about namespace deletion.

Concept Snapshot

Creating a custom namespace:
- Write a YAML file with kind: Namespace and metadata.name
- Run 'kubectl apply -f filename.yaml' to create it
- Verify with 'kubectl get namespaces'
- Use the namespace in pod/deployment specs
- Deleting the namespace removes all contained resources

Full Transcript

To create a custom namespace in Kubernetes, first write a YAML file defining the namespace with kind: Namespace and a unique name. Then apply this file using 'kubectl apply -f'. This sends the request to the Kubernetes API server, which creates the namespace resource in the cluster. You can verify the namespace exists by listing namespaces with 'kubectl get namespaces'. After creation, you can create pods or deployments inside this namespace by specifying it in their specs. If you delete the namespace, all resources inside it are also deleted. This process helps organize and isolate resources in your cluster.