How to Manage Kubernetes Containers

This post will cover topic related to ‘How to Manage Kubernetes Containers’ with multiple docker command examples and different scenerios. So this will help you to understand the command docker and options available in it. Also this post will explain you how to use docker command.

In Docker, managing containers is crucial for deploying and orchestrating applications. Kubernetes, a powerful container orchestration platform, plays a key role in managing these containers efficiently.

Let’s explore various commands related to managing Kubernetes containers:

1. Creating a Kubernetes Pod:
To create a pod named “nginx” with a single container running Nginx:

docker run --name nginx-pod --image nginx

This command creates a new pod with the Nginx container inside. Verify by checking the pod status:

kubectl get pods

Output example:

    NAME        READY   STATUS    RESTARTS   AGE
    nginx-pod   1/1     Running   0          30s
    

2. Inspecting a Pod:
To get detailed information about a specific pod:

kubectl describe pod nginx-pod

This command provides comprehensive details about the pod, including its IP address, status, and associated events.

3. Deleting a Pod:
To delete a pod named “nginx-pod”:

kubectl delete pod nginx-pod

Verify deletion by listing all pods:

kubectl get pods

Output example showing no pods:

    No resources found in default namespace.
    

4. Scaling Deployments:
To scale a deployment named “myapp” to 3 replicas:

kubectl scale --replicas=3 deployment/myapp

This scales the number of replicas of the “myapp” deployment to 3 instances.

5. Updating Container Image:
To update the image of a deployment “myapp” to a new version:

kubectl set image deployment/myapp nginx=nginx:1.19

This updates the Nginx container in the “myapp” deployment to version 1.19. Verify by checking deployment status:

kubectl rollout status deployment/myapp

Output example showing rollout complete:

    deployment "myapp" successfully rolled out
    

6. Executing Commands in Containers:
To execute a shell command inside a running container “nginx-pod”:

kubectl exec -it nginx-pod -- /bin/bash

This opens an interactive shell session inside the “nginx-pod” container, allowing command execution and verification of container state and logs.

7. Port Forwarding:
To forward a local port to a port in a pod “nginx-pod”:

kubectl port-forward nginx-pod 8080:80

This command forwards local port 8080 to port 80 of the “nginx-pod”, enabling direct access to the pod’s service.

8. Viewing Logs:
To view logs of a container “nginx” in pod “nginx-pod”:

kubectl logs nginx-pod -c nginx

This retrieves the logs generated by the “nginx” container within the “nginx-pod”, aiding in troubleshooting and monitoring.

9. Applying Resource Configuration:
To apply a YAML file defining a pod configuration:

kubectl apply -f pod.yaml

Where “pod.yaml” contains the pod configuration details. Verify by checking pod status:

kubectl get pods

Output example showing the newly created pod:

    NAME          READY   STATUS    RESTARTS   AGE
    nginx-pod     1/1     Running   0          1m
    

10. Monitoring Pod Resource Usage:
To view CPU and memory usage of pods:

kubectl top pod nginx-pod

This command displays resource usage metrics for the “nginx-pod”, helping in performance monitoring and capacity planning.

Also check similar articles.

How to Manage Kubernetes Container Checkpoints
How to Manage Kubernetes Build Processes
Search Kubernetes for Docker Images
Log out from Kubernetes Registry
Log in to Kubernetes Registry