> ## 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 Imperative Commands optional
> This article provides an overview of imperative commands in Kubernetes for creating and managing pods, services, deployments, and namespaces.
In this lesson, we guide you through imperative commands in Kubernetes. Gain practical experience creating pods, services, deployments, and namespaces imperatively—an invaluable exercise for exam preparation and day-to-day operations.
─────────────────────────────
## Deploying Pods Imperatively
### Deploying an Nginx Pod
Start by deploying an Nginx pod named "nginx-pod" using the `nginx:alpine` image. Run the following command:
```bash theme={null}
kubectl run nginx-pod --image=nginx:alpine
```
You should see output similar to:
```bash theme={null}
pod/nginx-pod created
```
─────────────────────────────
### Deploying a Redis Pod with Labels
Next, deploy a Redis pod using the `redis:alpine` image and assign it the label `tier=db`. The `--labels` option accepts key-value pairs and supports multiple labels separated by commas. The image below illustrates deploying a Redis pod with the specified label:
Execute this command:
```bash theme={null}
kubectl run redis --image=redis:alpine --labels="tier=db"
```
─────────────────────────────
## Creating Services
### Exposing the Redis Application
To expose the Redis pod on port 6379, create a ClusterIP service named "redis-service". Although the command `kubectl create service clusterip` exists, it does not support specifying selectors. Instead, use the `kubectl expose` command, which automatically uses the pod’s labels as selectors.
For example, run:
```bash theme={null}
kubectl expose pod redis --port=6379 --name=redis-service
```
Afterwards, verify the service with:
```bash theme={null}
kubectl get svc redis-service
```
Expected output:
```text theme={null}
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
redis-service ClusterIP 10.43.56.187 6379/TCP 12s
```
Below are additional examples showcasing various usages of the `kubectl expose` command:
```bash theme={null}
kubectl expose rc nginx --port=80 --target-port=8000
kubectl expose -f nginx-controller.yaml --port=80 --target-port=8000
kubectl expose pod valid-pod --port=444 --name=frontend
kubectl expose service nginx --port=443 --target-port=8443 --name=nginx-https
kubectl expose rc streamer --port=4100 --protocol=UDP --name=video-stream
kubectl expose rs nginx --port=80 --target-port=8000
kubectl expose deployment nginx --port=80 --target-port=8000
```
### Understanding `kubectl create service clusterip`
Running the following command without providing a name will result in an error:
```bash theme={null}
kubectl create service clusterip
```
Output:
```bash theme={null}
error: exactly one NAME is required, got 0
See 'kubectl create service clusterip --help' for help and examples
```
To create a ClusterIP service named "my-cs" mapping port 5678 to target port 8080, use:
```bash theme={null}
kubectl create service clusterip my-cs --tcp=5678:8080
```
For a headless service, specify:
```bash theme={null}
kubectl create service clusterip my-cs --clusterip='None'
```
Since the `kubectl create service clusterip` command does not allow specifying selectors, using `kubectl expose` is the recommended approach.
For more details on exposing the Redis application, refer to the image below:
─────────────────────────────
## Creating a Deployment
Create a deployment named "webapp" using the `kodekloud/webapp-color` image and then scale it to three replicas. Execute the following commands:
```bash theme={null}
kubectl create deployment webapp --image=kodekloud/webapp-color
kubectl scale deployment webapp --replicas=3
```
You should see:
```bash theme={null}
deployment.apps/webapp created
```
Use the command below to check that all three replicas are running:
```bash theme={null}
kubectl get deployments
```
─────────────────────────────
## Creating a Pod with a Specific Container Port
Next, create a pod called "custom-nginx" using the nginx image and configure it to expose container port 8080:
```bash theme={null}
kubectl run custom-nginx --image=nginx --port=8080
```
This configures the pod so that the container listens on port 8080.
─────────────────────────────
## Managing Namespaces and Deployments
### Creating a Namespace
To organize your resources, create a new namespace called "dev-ns":
```bash theme={null}
kubectl create namespace dev-ns
```
### Deploying in a Specific Namespace
Within the "dev-ns" namespace, deploy a new deployment named "redis-deploy" using the Redis image, scaled to two replicas:
```bash theme={null}
kubectl create deployment redis-deploy --image=redis --replicas=2 -n dev-ns
```
Verify the deployment using:
```bash theme={null}
kubectl get deployment -n dev-ns
```
Expected output:
```text theme={null}
NAME READY UP-TO-DATE AVAILABLE AGE
redis-deploy 2/2 2 2 12s
```
─────────────────────────────
## Creating a Pod and Exposing It as a Service in One Step
In this task, create a pod named "httpd" using the `httpd:alpine` image in the default namespace and simultaneously expose it as a ClusterIP service on port 80. The `kubectl run` command supports the `--expose` option to automatically create a service.
Run the command below:
```bash theme={null}
kubectl run httpd --image=httpd:alpine --port=80 --expose=true
```
You should see:
```bash theme={null}
pod/httpd created
```
Then, verify that both the pod and its corresponding service have been created:
```bash theme={null}
kubectl get pod httpd
kubectl get svc httpd
```
To view detailed service information, run:
```bash theme={null}
kubectl describe svc httpd
```
This confirms that the service has the correct selector (e.g., `run=httpd`), target port (80/TCP), and that endpoints are automatically discovered.
For a visual outline of the creation process, refer to the diagram below:
─────────────────────────────
## Final Verification
Verify your Kubernetes resources by listing all pods:
```bash theme={null}
kubectl get pod
```
Sample output:
```text theme={null}
NAME READY STATUS RESTARTS AGE
nginx-pod 1/1 Running 0 12m
redis 1/1 Running 0 10m
webapp-7b59bf687d-n7xxp 1/1 Running 0 5m49s
webapp-7b59bf687d-rds95 1/1 Running 0 5m4s
webapp-7b59bf687d-4gqmt 1/1 Running 0 5m4s
custom-nginx 1/1 Running 0 3m41s
httpd 1/1 Running 0 8s
```
Next, verify your services:
```bash theme={null}
kubectl get svc
```
Expected output:
```text theme={null}
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.43.0.1 443/TCP 20m
redis-service ClusterIP 10.43.56.187 6379/TCP 6m35s
httpd ClusterIP 10.43.112.233 80/TCP 15s
```
Finally, describe the "httpd" service for full configuration details:
```bash theme={null}
kubectl describe svc httpd
```
This command confirms the service's selector, ClusterIP, exposed ports, and endpoints.
─────────────────────────────\
This concludes our lesson on imperative commands in Kubernetes. By following these steps, you have practiced creating and managing pods, services, deployments, and namespaces using imperative commands. For more detailed information, consider exploring the [Kubernetes Documentation](https://kubernetes.io/docs/) to expand your knowledge further.
Imperative commands are great for quick testing and learning; however, for production deployments, consider using declarative configurations for better maintainability.