> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Exploring Kubernetes Cluster

> This guide covers inspecting a GKE cluster, listing nodes, viewing namespaces, deploying an NGINX app, and preparing namespaces for GitLab CI/CD.

This guide walks you through inspecting a Google Kubernetes Engine (GKE) cluster. You’ll learn how to list nodes, view namespaces, deploy a sample NGINX app with Ingress, verify your kubeconfig, and prepare namespaces for GitLab CI/CD.

## Inspecting Cluster Nodes on GKE

<Callout icon="lightbulb" color="#1CB2FE">
  Make sure you’ve authenticated with GKE and set up `kubectl` (or aliased as `k`) using:

  ```bash theme={null}
  gcloud container clusters get-credentials <CLUSTER_NAME> --zone <ZONE> --project <PROJECT_ID>
  ```
</Callout>

List your cluster’s worker nodes:

```bash theme={null}
k get nodes
```

Example output:

```bash theme={null}
NAME                                         STATUS   ROLES     AGE   VERSION
gke-cluster-1-default-pool-36b5f551-hzvn     Ready    <none>    20m   v1.29.0-gke.1381000
gke-cluster-1-default-pool-36b5f551-rsc0     Ready    <none>    20m   v1.29.0-gke.1381000
```

These nodes are running Kubernetes v1.29.0.

## Viewing Namespaces and the NGINX Ingress Controller

Show all namespaces:

```bash theme={null}
k get namespaces
```

Locate the `ingress-nginx` namespace and inspect its resources:

```bash theme={null}
k -n ingress-nginx get all
```

You should see:

* A Deployment managing the Ingress Controller pod
* A `LoadBalancer` Service exposing a public IP

## Deploying a Sample NGINX Application

In the `default` namespace, the following resources route traffic through the Ingress Controller:

```bash theme={null}
k -n default get all
k -n default get ingress
```

Sample output:

```bash theme={null}
# Pods, Services, Deployments
pod/nginx-deploy-d845cc945-hnj2v          1/1 Running   0        8m
service/nginx-deploy                     ClusterIP    10.96.14.252   80/TCP    8m
deployment.apps/nginx-deploy             1/1          1              8m

# Ingress
nginx-demo   <none>   nginx-default.34.82.207.123.nip.io   34.82.207.123   80,443   7m
```

Copy the Ingress host into your browser. You may encounter a security warning due to a self-signed certificate:

<Callout icon="triangle-alert" color="#FF6B6B">
  The default Ingress TLS certificate is self-signed. Browsers will warn before displaying the NGINX welcome page.
</Callout>

<Frame>
  ![The image shows a browser displaying the default "Welcome to nginx!" page, indicating that the nginx web server is successfully installed and running.](https://kodekloud.com/kk-media/image/upload/v1752877198/notes-assets/images/GitLab-CICD-Architecting-Deploying-and-Optimizing-Pipelines-Exploring-Kubernetes-Cluster/nginx-welcome-page-browser-display.jpg)
</Frame>

This confirms external traffic is routed correctly.

## Configuring kubectl and kubeconfig for CI/CD

To automate deployments in GitLab CI, ensure `kubectl` is installed and authenticated via kubeconfig.

Check client and server versions:

```bash theme={null}
kubectl version --short
```

```bash theme={null}
Client Version: v1.29.1
Server Version: v1.29.0-gke.1381000
```

View the active kubeconfig context:

```bash theme={null}
kubectl config view --minify
```

```yaml theme={null}
apiVersion: v1
clusters:
- cluster:
    server: https://35.230.61.213
    certificate-authority-data: DATA+OMITTED
  name: gke_clgcporg8-090_us-west1-a_cluster-1
contexts:
- context:
    cluster: gke_clgcporg8-090_us-west1-a_cluster-1
    namespace: kube-system
    user: gitlab-cluster-admin
  name: gke_clgcporg8-090_us-west1-a_cluster-1
users:
- name: gitlab-cluster-admin
  user:
    token: REDACTED
```

A dedicated user or service account (e.g., `gitlab-cluster-admin`) should authenticate your GitLab CI jobs.

## Creating Namespaces for Environments

Instead of separate clusters, use dedicated namespaces to isolate **development** and **staging** workloads:

```bash theme={null}
k create namespace development
k create namespace staging
```

```bash theme={null}
namespace/development created
namespace/staging created
```

Verify all namespaces:

```bash theme={null}
k get namespaces
```

```bash theme={null}
NAME                  STATUS   AGE
default               Active   30m
development           Active   1m
staging               Active   1m
ingress-nginx         Active   25m
kube-system           Active   30m
```

Your cluster is now prepared for GitLab CI pipelines targeting **development** and **staging**.

## Kubernetes CLI Command Reference

| Command                            | Description                          |
| ---------------------------------- | ------------------------------------ |
| `kubectl get nodes`                | List all cluster nodes               |
| `kubectl get namespaces`           | Show active namespaces               |
| `kubectl -n ingress-nginx get all` | Inspect Ingress Controller resources |
| `kubectl get ingress`              | Display all Ingress resources        |
| `kubectl config view --minify`     | Show current kubeconfig context      |
| `kubectl create namespace <name>`  | Create a new namespace               |

## Links and References

* [Google Kubernetes Engine (GKE)](https://cloud.google.com/kubernetes-engine)
* [Kubernetes Ingress NGINX Controller](https://kubernetes.github.io/ingress-nginx/)
* [kubectl CLI Reference](https://kubernetes.io/docs/reference/kubectl/)
* [GitLab CI/CD Pipeline Configuration](https://docs.gitlab.com/ee/ci/)

<CardGroup>
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