KUBERNETES CLUSTER MANAGEMENT

What is a Kubernetes Namespace?

A Kubernetes namespace is a way to divide cluster resources between multiple users or applications. Namespaces are a method for partitioning a single Kubernetes cluster into multiple virtual clusters, allowing you to organize and manage your resources more efficiently.

Why Use Namespaces?

1. Resource Management: Helps manage resources and prevent conflicts by isolating environments.
2. Access Control: Facilitates different levels of access and permissions for different teams or applications.
3. Environment Separation: Allows the separation of different environments like development, testing, and production within the same cluster.
4. Organization: Simplifies the organization of resources, making it easier to manage large clusters with many resources.

Simple Terms

Imagine a Kubernetes cluster as an apartment building, and namespaces are the individual apartments within the building:

• Apartment Building (Cluster): The whole building represents the Kubernetes cluster.
• Apartments (Namespaces): Each apartment is a separate namespace. Different people (teams or applications) live in different apartments, each with its own space and resources.
• Rooms (Resources): Within each apartment, there are rooms like the kitchen, bedroom, etc. These rooms represent Kubernetes resources (like pods, services, and deployments) within a namespace.

Key Points

1. Isolation: Just as each apartment is isolated from others, namespaces provide a scope for resources, preventing interference between resources in different namespaces.
2. Shared Resources: The apartment building’s common resources (like the lobby or gym) are analogous to cluster-wide resources that are not specific to any namespace.
3. Access Control: You can control who has access to which apartment, similar to how you manage access to different namespaces.

How Do Namespaces Work in Kubernetes?

Enough of theory. Let's see namespaces in action. The basic usage of namespaces is the same as with any other objects in Kubernetes. It means you can execute commands like kubectl create or kubectl get for namespaces. Let's try that.

Creation and deletion of namespaces are described in the Admin Guide documentation for namespaces.

Viewing namespaces

You can list the current namespaces in a cluster using:

kubectl get namespace

 

NAME              STATUS   AGE

default           Active   1d

kube-node-lease   Active   1d

kube-public       Active   1d

kube-system       Active   1d

Setting the namespace for a request

To set the namespace for a current request, use the --namespace flag.

For example:

first create a unique namepace with the below 

 kubectl create namespace dev

kubectl run nginx --image=nginx --namespace=<insert-namespace-name-here>

kubectl get pods --namespace=<insert-namespace-name-here>

Setting the namespace preference

You can permanently save the namespace for all subsequent kubectl commands in that context.

kubectl config set-context --current --namespace=<insert-namespace-name-here>

# Validate it

kubectl config view --minify | grep namespace: