> ## 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.

# Solution Namespace

> This article explains how to manage Kubernetes namespaces, including listing, counting, and deploying resources, as well as using DNS-based service discovery.

In this solution walkthrough, we’ll explore how to list and count namespaces, inspect pods within them, deploy resources, and leverage DNS-based service discovery both within the same namespace and across namespaces.

## 1. List and Count Namespaces

You can view all namespaces in your cluster using:

```bash theme={null}
kubectl get namespaces
# or shorthand
kubectl get ns
```

| Command                  | Description                      |
| ------------------------ | -------------------------------- |
| `kubectl get namespaces` | List all namespaces (full form)  |
| `kubectl get ns`         | List all namespaces (short form) |

Example output:

```txt theme={null}
NAME              STATUS   AGE
default           Active   6m55s
kube-system       Active   6m54s
kube-public       Active   6m54s
kube-node-lease   Active   6m54s
finance           Active   32s
marketing         Active   32s
dev               Active   32s
prod              Active   32s
manufacturing     Active   32s
research          Active   32s
```

There are **10** namespaces in total.

<Callout icon="lightbulb" color="#1CB2FE">
  You can add `-o wide` or use `-o jsonpath` to customize the output format.
</Callout>

## 2. Count Pods in the `research` Namespace

To see how many pods are running in `research`:

```bash theme={null}
kubectl get pods -n research
```

Example:

```txt theme={null}
NAME   READY  STATUS             RESTARTS   AGE
dna-2  0/1    CrashLoopBackOff   3          76s
dna-1  0/1    CrashLoopBackOff   3          76s
```

There are **2** pods in this namespace.

## 3. Create a Pod in the `finance` Namespace

Deploy a Redis pod into `finance`:

```bash theme={null}
kubectl run redis --image=redis -n finance
```

Verify the pod:

```bash theme={null}
kubectl get pods -n finance
```

Example:

```txt theme={null}
NAME     READY  STATUS              RESTARTS   AGE
payroll  1/1    Running             0          2m20s
redis    0/1    ContainerCreating   0          8s
```

## 4. Locate the `blue` Pod Across All Namespaces

To identify which namespace hosts the `blue` pod:

```bash theme={null}
kubectl get pods --all-namespaces
# or shorthand
kubectl get pods -A
```

Sample output shows `blue` in `marketing`:

```txt theme={null}
NAMESPACE    NAME   READY  STATUS           RESTARTS   AGE
marketing    blue   1/1    CrashLoopBackOff 4          3m3s
...
```

## 5. Service DNS Within the Same Namespace

Services in the same namespace can be reached by `<service-name>:<port>`. In `marketing`:

```bash theme={null}
kubectl get svc -n marketing
```

Example:

```txt theme={null}
NAME           TYPE       CLUSTER-IP      PORT(S)
blue-service   NodePort   10.43.82.162    8080:30082/TCP
db-service     NodePort   10.43.134.33    6379:30758/TCP
```

The `blue` app connects to `db-service` on:

* **Host**: `db-service`
* **Port**: `6379`

<Frame>
  ![The image shows a "Connectivity Test" interface with fields for "Host Name" and "Host Port," and a "TEST" button. The result indicates "Success!" for the connection test.](https://kodekloud.com/kk-media/image/upload/v1752880798/notes-assets/images/Kubernetes-and-Cloud-Native-Security-Associate-KCSA-Solution-Namespace/connectivity-test-interface-success.jpg)
</Frame>

## 6. Service DNS Across Namespaces

Accessing a service in a different namespace (e.g., `dev`) requires the full DNS name:

```text theme={null}
db-service.dev.svc.cluster.local:6379
```

Verify the service definition:

```bash theme={null}
kubectl get svc -n dev
```

Example:

```txt theme={null}
NAME        TYPE        CLUSTER-IP      PORT(S)
db-service  ClusterIP   10.43.252.9     6379/TCP
```

<Callout icon="triangle-alert" color="#FF6B6B">
  Always use the full DNS (`<svc>.<namespace>.svc.cluster.local`) when connecting across namespaces to avoid resolution errors.
</Callout>

***

## Links and References

* [Kubernetes Namespaces](https://kubernetes.io/docs/concepts/overview/working-with-objects/namespaces/)
* [kubectl Cheat Sheet](https://kubernetes.io/docs/reference/kubectl/cheatsheet/)
* [Service DNS in Kubernetes](https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/)

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