What is Kubernetes?
Kubernetes is an open-source container management tool hosted by Cloud Native Computing Foundation (CNCF). Kubernetes is a platform that eliminates the manual processes involved in deploying containerized applications. It is also known as ‘k8s’. Kubernetes is an extensible, portable, and open-source platform designed by Google in 2014.
As the definition says, Kubernetes or k8s is an open-source orchestration and cluster management for container-based applications maintained by the Cloud Native Computing Foundation.
The official Kubernetes (k8s) website says,
Kubernetes is an open-source system for automating deployment, scaling, and management of containerized applications. It groups containers that make up an application into logical units for easy management and discovery. Kubernetes builds upon 15 years of experience of running production workloads at Google, combined with best-of-breed ideas and practices from the community.
In simple words, Kubernetes makes it easy to manage containers on multiple hosts. Also, it makes the container deployment so easy using a declarative YAML file.
You specify how you want the container to be deployed, and Kubernetes takes care of it by reading the information provided in the YAML.
As per the state of Kubernetes report by Splunk 96% of organizations are either using or evaluating Kubernetes and 5.6 million developers are using kubernetes today. Also, there has been a more than 300% increase in container production usage in the past 5 years.
Now, before moving forward in this tutorial, let me just quickly brief you about containerization.
What is Containers?
Containers create a virtualization environment that allows us to run multiple applications or operating systems without interrupting each other. Containers are lightweight because they don’t need the extra load of a hypervisor. They can directly run within the host machine.
Before containers came into existence, the developers and the testers always had arguments between them. This usually happened because what worked on the developer’s side would not work on the testing side. Actually, both of them existed in different environments.
To avoid such scenarios, containers were introduced to keep both the Developers and Testers on the same page.
But handling a large number of containers altogether was also a problem. Sometimes, while running containers, few issues were raised on the product side, which was not present at the development stage. This kind of scenario introduced the Container Orchestration System.
Challenges Without Container Orchestration
As you can see in the above diagram, when multiple services run inside containers, you may want to scale these containers. In large scale industries, this is really tough to do. That’s because it would increase the cost of maintaining services and the complexity of running them side-by-side.
So to avoid setting up services manually & overcome the challenges, something big was needed. This is where Container Orchestration Engine comes into the picture.
This container orchestration lets us organize multiple containers to launch all the underlying machines, and containers are healthy and distributed in a clustered environment. In today’s world, there are mainly two such engines: Kubernetes & Docker Swarm.
Kubernetes vs Docker Swarm
Kubernetes and Docker Swarm are leading container orchestration tools in today’s market. So before using them in production, we should know what exactly they are and how they work.
I would also like to remind you that people misunderstand Docker Swarm and Docker. Docker is just a containerization platform. Docker Swarm is a container orchestration platform, the same as Kubernetes.
The differences between Kubernetes vs Docker Swarm are briefly summarized in the below table.
If I could choose my pick between the two, it would have to be Kubernetes since containers need to be managed and connected to the outside world for scheduling, load balancing, and distribution.
But, if you think logically, Docker Swarm would make a better option, as it runs on top of Docker, right? If I were you, I would have definitely got confused about which tool to use. But hey, Kubernetes is an undisputed leader in the market and runs on top of Docker containers with better functionalities.
Why do we need Kubernetes?
The first question when it comes to Kubernetes or a container orchestrator is why we need it. Let’s understand it from two real-world examples.
Container Deployments
Let’s say you have a couple of Java applications. You can package it into a container and run it on a server containing a Docker engine or any container engine. For this scenario, there is no complexity.
You package your application into a Docker image using Dockerfile and expose a port on a host for the external world to access it.
However, the downside is that it can be a single point of failure, as it is only running on a single server. To handle the single point of failure, you need an efficient mechanism.
This is why you need a container orchestration tool like Kubernetes to scale applications on-demand and withstand single-node failures.
Kubernetes helps in scaling applications, self-healing, and rolling updates, making it well-suited for running containers.
Microservices Deployment/Orchestration
Now, let’s say, you have a big application that is composed of microservices (APIs, UI, user management, credit card transaction system, etc). All these microservice components have to talk to each other using REST APIs or other protocols.
As the application has many components or microservices, we cannot deploy all the services in one server or a container. The applications have to be decoupled and each microservice should be deployed and scaled on its own. This makes application development and deployment easier and faster.
In this scenario, the complexity lies in networking, shared file systems, load balancing, and service discovery. Here is where Kubernetes comes into the picture. It helps in orchestrating complex processes in a manageable way.
Using Kubernetes, you just have to worry about your application development and deployments.
All heavy lifting like networking, service-to-service communication across nodes, load balancing, service discovery, resource scheduling, scalability, and high availability are taken care of by Kubernetes.
Overall Kubernetes helps you achieve the following.
- Self Healing
- Automatic Container Scheduling
- Horizontal and Vertical Scaling
- Rolling application upgrades and downgrades with zero downtime
That’s all about the What is Kubernetes and why do we need Kubernetes. If you have any queries or feedback, please write us email at contact@waytoeasylearn.com. Enjoy learning, Enjoy Kubernetes.!!