BLOG02a: Understanding Kubernetes Contexts

When you start working with Kubernetes, one of the first tools you use is kubectl. But did you know that kubectl can talk to multiple clusters, with different users and namespaces—all from one file? This magical piece of configuration is called a context.

In this blog, we’ll break down:

• What exactly a Kubernetes context is

• Why it is important

• How kubectl chooses which cluster you talk to

• How to create your own contexts

• How to map contexts to specific clusters, users, and namespaces

This is an essential concept for every DevOps and Kubernetes student.

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🔹 What is a Kubernetes Context?

A context in Kubernetes is a shortcut that tells kubectl:

“Which cluster should I connect to?” “Who am I when I connect?” “Which namespace should I work in?”

A context is made of three things:

Part	Meaning
cluster	The Kubernetes API server you talk to
user	The identity (cert/token) you authenticate with
namespace	The default namespace for commands

Think of a context like a profile for using kubectl.

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🔹 Where Are Contexts Stored?

In the kubeconfig file:

~/.kube/config

Run this to see all contexts:

kubectl config get-contexts

Example output:

CURRENT   NAME               CLUSTER      AUTHINFO      NAMESPACE
*         dev-context        dev-cluster  dev-user      dev
          prod-context       prod-cluster prod-user     production

The * indicates the current context kubectl is using.

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🔹 Why Are Contexts Important?

❗ Prevent mistakes

Imagine running a delete command in production by accident!

kubectl delete pod myapp

If your current context is production… that's a disaster.

Contexts help you separate environments like:

• development

• staging

• production

• testing

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🔹 Check Your Current Context

kubectl config current-context

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🔹 How kubectl Uses Context

Every kubectl command automatically uses the current context.

Example:

kubectl get pods

This gets pods in:

• the cluster of the current context

• the namespace of the current context

Unless you override it with:

-n <namespace>
--context <context>

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🔹 Creating a New Context (Step-by-Step)

Let’s create a context manually.

Step 1: Create a cluster entry

This points to an API server.

kubectl config set-cluster my-cluster \
  --server=https://10.0.0.1:6443 \
  --certificate-authority=/path/to/ca.crt

Step 2: Create a user entry

This defines authentication.

kubectl config set-credentials my-user \
  --client-certificate=/path/to/user.crt \
  --client-key=/path/to/user.key

Step 3: Create the context

Combine cluster + user + namespace:

kubectl config set-context my-context \
  --cluster=my-cluster \
  --user=my-user \
  --namespace=my-namespace

Step 4: Switch to that context

kubectl config use-context my-context

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🔹 Create Context Mapping to a Specific Namespace

You can set default namespace:

kubectl config set-context dev-context \
  --cluster=dev-cluster \
  --user=dev-user \
  --namespace=dev

Now running:

kubectl get pods

is equal to:

kubectl get pods -n dev

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🔹 How to Change Namespace Only (Without Creating New Context)

kubectl config set-context --current --namespace=my-namespace

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🔹 How to Rename a Context

kubectl config rename-context old-name new-name

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🔹 How to Delete a Context

kubectl config delete-context my-context

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🔹 Real-Life Example (Best Practice for DevOps)

A common setup:

Environment	Context Name	Namespace
Development	dev-context	dev
Staging	stg-context	staging
Production	prod-context	prod

You switch safely:

kubectl config use-context prod-context

And double-check:

kubectl config current-context

This prevents mistakes in production.

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🔹 Quick Cheat Sheet

# Show contexts
kubectl config get-contexts

# Show current context
kubectl config current-context

# Switch context
kubectl config use-context <context>

# Set namespace for current context
kubectl config set-context --current --namespace <ns>

# Create new context
kubectl config set-context <name> --cluster=<c> --user=<u> --namespace=<ns>

# Delete context
kubectl config delete-context <name>

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🎓 Conclusion

Kubernetes contexts are one of the simplest but most powerful concepts in cluster administration.

They help you:

• Organize access to multiple clusters

• Map namespaces to default views

• Prevent production mistakes

• Switch environments effortlessly

Every DevOps engineer must understand and use them daily.