Kubernetes: A Beginner’s Guide to Container Orchestration

What is Kubernetes?

Kubernetes (also known as k8s or “kube”) is an open source container orchestration platform that automates many of the manual processes involved in deploying, managing, and scaling containerized applications.

To understand Kubernetes, let’s first understand two things — Container and Orchestration.

What are containers?

Containers are completely isolated environments, as in they can have their own processes or services, their own network interfaces, their own mounts, just like Virtual machines, except that they all share the same OS kernel.

Why we need a containers?

Imagine you’re building a complex application with many parts like a web server, a database, and more. It’s a headache to make sure all these parts work well together on different computers. Sometimes, they don’t like the same operating system, or they want different versions of helper tools.

With containerization technique, it’s like putting each part of your application in its own box (container). These boxes have everything the part needs to run — no matter what computer they’re on. So, you don’t worry about compatibility issues between the parts and the computer.

When a new person joins your team, instead of them spending hours setting up their computer just right, they can use Docker to create the same boxes you’re using. It’s like giving them a pre-packaged kit that works the same for everyone.

Docker makes sure your app runs the same way in development, testing, and when it’s live. It takes away the headaches of dealing with compatibility problems and makes the whole process of building and sharing applications much simpler and smoother.

What docker can do?

Docker provides a containerization platform that packages applications and their dependencies, ensuring consistency across different environments. Containers enable developers to package an application along with its dependencies, libraries, and configuration settings in a standardized unit. This eliminates compatibility issues, simplifies the setup process, and ensures that the application runs consistently across various environments. With Docker, developers can create reproducible and isolated environments, making it easier to develop, build, and ship applications.

How docker works?

Docker works by leveraging the shared kernel of the host operating system. Imagine an operating system like Ubuntu — it consists of an OS kernel responsible for hardware interaction and additional software that makes it unique. Docker containers utilize this shared kernel concept. If you have Ubuntu with Docker, you can run containers based on different Linux distributions like Debian or Fedora, as long as they share the same kernel. Unlike hypervisors that virtualize entire operating systems, Docker is designed for containerizing applications. Each Docker container includes only the specific software that makes an operating system unique.

How it’s actually done?

Containerizing applications with Docker is made easy by leveraging existing images available on public registries like Docker Hub. Many organizations already have their products containerized and accessible on these platforms. After installing Docker on your host, deploying an application stack becomes as simple as using the “docker run” command with the desired image name.

For instance, running “docker run ansible” launches an instance of Ansible on the Docker host. Similarly, you can run instances of MongoDB, Redis, and Node.js with their respective “docker run” commands. To run a web service, you just point to the location of the code repository on the host. Scaling is straightforward — add more instances as needed and set up a load balancer for distribution. If an instance fails, it can be easily replaced by destroying and launching a new one. Additional solutions for handling such scenarios can be explored further in this course. Docker’s simplicity and versatility streamline the process of managing and scaling applications.

What is container orchestration?

After packaging your application into a Docker container, the next step is to run it in production efficiently. When your application depends on other containers, like databases or messaging services, and you need to handle scaling based on varying user loads, you require a robust platform with adequate resources. This platform should orchestrate the connections between containers and automatically scale the application up or down depending on the demand. This entire process of automating the deployment and management of containers is termed Container Orchestration. It ensures seamless coordination between containers and facilitates automatic scaling to handle fluctuations in usage, making it a crucial aspect of running applications in a production environment.

Different Orchestration Technologies:

Kubernetes is thus a container orchestration technology. There are multiple such technologies available today — Docker has its own tool called Docker Swarm. Kubernetes from Google and Mesos from Apache. While Docker Swarm is really easy to setup and get started, it lacks some of the advanced autoscaling features required for complex applications. Mesos on the other hand is quite difficult to setup and get started, but supports many advanced features. Kubernetes — arguably the most popular of it all — is a bit difficult to setup and get started but provides a lot of options to customize deployments and supports deployment of complex architectures. Kubernetes is now supported on all public cloud service providers like GCP, Azure and AWS and the kubernetes project is one of the top ranked projects in Github.

Various advantages of Using Kubernetes:

1. High Availability: Multiple instances of your application run on different nodes, ensuring resilience against hardware failures.
2. Load Balancing: User traffic is evenly distributed across containers, optimizing performance.
3. Seamless Scaling: Kubernetes allows for effortless scaling of instances based on demand, ensuring quick response to varying workloads.
4. Resource Management: Scale nodes up or down without application downtime, efficiently managing hardware resources.
5. Declarative Configuration: Kubernetes simplifies complex processes through declarative object configuration files, providing a standardized and customizable approach to deployment.

Exploring Kubernetes opens the door to a more efficient and scalable approach to building and deploying applications.

Thanks for reading! Until next time happy cloud computing!