In this article, we will take a look at Kubernetes, the difference between Kubernetes and Docker, and how to deploy Spring boot application in Kubernetes.
Kubernetes is an open-source container orchestration and management tool.
Kubernetes can manage the container’s lifecycle.
Furthermore, it can perform operations like container deployment, scaling-up & scaling-down the containers along with container load balancing for you.
Before taking a look at Kubernetes, let’s understand what is docker and container.
What is docker?
The idea behind Docker is to create lightweight and portable containers for software applications that can run on any machine with Docker installed.
When you work on real-world enterprise applications, your application might have dependencies on third-party applications and libraries.
Therefore, the deployment of the application on the customer site is always challenging.
You may have to install the latest java, tomcat, maven, etc.
The docker allows you to put all dependencies which are required by your application in the container (box).
And you can take that container to any machine that has Docker installed and run your application without worrying about those dependencies.
What is Kubernetes?
Containers are becoming the standard in packaging and deploying application code.
But when we work on complex applications like microservices-based architecture, there could be numerous containers interconnected with each other.
Imagine using Docker and creating an infrastructure made up of numerous containers.
Once a certain degree of complexity has been reached, Docker struggles to manage the activation and deactivation of the containers and all the other management operations.
Here Kubernetes or K8s is useful.
Kubernetes is undoubtedly one of the most successful concepts or technologies around dockers/containers.
Initially created by Google, Kubernetes is an opensource platform to automate the deployment, scaling of applications, as managing the application containers.
In simple words, Kubernets allows you to focus on solving the business problem and forget about the infrastructure and deployment problems.
Before we get to work, we have to understand a few concepts:
Cluster: Set of physical or virtual machines and other resources used by Kubernetes.
Pods: They are the smallest deployable unit (set of containers and volumes) that can be created, managed by Kubernetes.
Replica: A replica is an exact copy of a Pod.
Replication Controllers: Pod Manager ensures that replicas are up and allows for easy scaling. It allows easy scaling of systems and handles the re-creation of a pod when a fault occurs.
Service: Defines how to access a group of Pods.
Difference between Docker and Kubernetes
Docker is a container management platform that makes it easier to create, deploy and run applications through the use of containers.
Additionally, Docker guarantees us that the container (application) will run in the same way on any computer or server.
On the other hand, Kubernetes is the tool to manage and organize the containers.
Therefore we can conclude that Docker and Kubernetes are not directly comparable products.
Docker has one more product that is called as Docker Swarm that can be comparable to Kubernetes.
Docker Swarm is the container orchestration tool developed by Docker. You can read about the docker swarm here.