In the world of container orchestration, Kubernetes has emerged as the go-to tool for managing and deploying containerized applications. Kubernetes, also known as K8s, is an open-source platform that automates the deployment, scaling, and management of containerized applications.
It was originally developed by Google and is now maintained by the Cloud Native Computing Foundation (CNCF).
In this article, we will introduce you to Kubernetes and explore its core concepts, architecture, and basic commands. By the end of this article, you will have a good understanding of Kubernetes and be ready to start using it.
Kubernetes Architecture
Kubernetes follows a client-server architecture where the user interacts with the Kubernetes API server to deploy, manage and monitor the containers. The Kubernetes cluster comprises the following components:
Master Node: The master node is responsible for managing the Kubernetes cluster. It includes the API server, etcd, scheduler, and controller manager.
Worker Node: The worker node is where the containers are deployed and run. It includes the kubelet, container runtime, and kube-proxy.
etcd: etcd is a distributed key-value store used by the Kubernetes master nodes to store configuration data.
Basic Kubernetes Commands
Before we dive into the architecture and concepts of Kubernetes, let's explore some basic Kubernetes commands that you will need to know.
kubectl version: This command shows the version of kubectl, Kubernetes API, and Kubernetes client libraries.
kubectl get nodes: This command shows the list of nodes in the Kubernetes cluster.
kubectl get pods: This command shows the list of running pods in the Kubernetes cluster.
kubectl create deployment: This command is used to create a deployment in Kubernetes.
kubectl delete deployment: This command is used to delete a deployment in Kubernetes.
Kubernetes Concepts
Now that we have seen some basic Kubernetes commands, let's dive into the core concepts of Kubernetes.
Pods: A pod is the smallest unit of deployment in Kubernetes. It is a logical host for one or more containers. All containers in a pod share the same network namespace and can communicate with each other using localhost.
ReplicaSets: A ReplicaSet is used to ensure that a specified number of replicas of a pod are running at any given time. If a pod fails, the ReplicaSet creates a new pod to replace it.
Deployments: A Deployment manages the deployment and scaling of a set of ReplicaSets. It allows for rolling updates, rollbacks, and scaling of applications.
Services: A Service is an abstraction that defines a logical set of pods and a policy by which to access them.
Step-by-Step Guide to Deploying an Application on Kubernetes
Now that we have a good understanding of Kubernetes concepts and basic commands, let's walk through a step-by-step guide to deploying an application on Kubernetes.
Create a Docker Image: The first step is to create a Docker image of your application. You can use any language or framework to create your application.
Create a Kubernetes Deployment: Next, create a Kubernetes Deployment using the kubectl create deployment command. This command creates a deployment with a single replica.
Scale the Deployment: To scale the deployment, use the kubectl scale command. This command allows you to increase or decrease the number of replicas.
Expose the Deployment as a Service: To expose the deployment as a service, use the kubectl expose deployment command. This command creates a service that exposes the deployment to the outside world.
Access the Application: To access the application, use the IP address of the service created in the previous step.
Kubernetes is a powerful tool that simplifies the deployment, scaling, and management of containerized applications.
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That's it for this post. Keep practicing and have fun. Leave your comments if any.