As apps grew bigger, product development became complex. Companies began adopting approaches like microservice architecture for developing bigger applications. However, deploying apps faster was still a challenge. So, companies had to look for ways to streamline the deployment process so they could deploy their applications faster. Hence, the concept of containers was introduced. In this blog, we are going to learn about containers and their orchestration using Docker & Kubernetes.
What are Containers?
Containers are virtual spaces in which we pack and isolate a piece of software with all the code, libraries, and dependencies it needs to run. The process is called containerization.
The idea behind containers and the containerization process is to create a virtual environment that is independent and free from what’s happening outside the container. For this reason, we decouple each container from the host operating system as well as other containers.
The concept of containers is derived from virtualization wherein we had multiple applications running on the same virtual machine. The problem with this approach was that any changes to the shared dependencies could affect all the applications.
To avoid this shared dependency conflict, businesses had to ensure they are only running one application per machine. While the approach could solve a major problem, it could lead to a lot of resource wastage.
Now, in order to resolve this conflict, the concept of containers is introduced. Here, applications are no longer dependent on the host operating system. Instead, they run in containers which are independent of what dependency changes are occurring in the operating system. This resources in lower resource utilization and less cost.
Structure of a Container
A container is made of two components:
1. Container Image: A package of an application and its dependency.
2. Container Engine: A program that runs applications in a container and isolates it from other applications running on the host operating system.
Advantages
1. Easy to deploy.
2. Capable of running on any device or any operating system.
3. Flexibility to create easily interchangeable application stack components.
4. Easily release security patches or roll back updates in container-based apps is easy.
5. Easily scale a containerized application to handle the additional load or conserve resources during less time.
Docker and Kubernetes are the tools we use to containerize apps and then manage & maintain those containers.
What is Docker?
A popular containerization platform that offers a toolset to create container images of applications. This way, Docker makes it easier to create, deploy, and run applications with the help of containers. It can be beneficial for both developers and system administrators who can use it as a part of many DevOps (Developers + Operations) toolchains.
Docker consists of the following components:
- Dockerd, a runtime container
- BuildKit, a container image builder
- Docker – CLI used to work with the builder, containers, and the engine
You can learn about Docker from here.
What is Kubernetes?
An open-source container orchestration tool using which we can deploy, scale, de-scale, and load balance containers.
Kubernetes offers facilities like automatic container scheduling, self-healing, horizontal scaling, automatic rollouts & rollbacks, configuration management, etc.
Orchestrating Docker Containers using Kubernetes
Kubernetes uses the master-slave communication model for orchestration where we have a master node and several worker nodes.
Master Node
The master node is responsible for controlling the container cluster. It has the following components:
1. API Server
The Kubernetes API server is responsible for managing the container cluster. This is where the Kubernetes APIs process and validate REST operations and update the corresponding objects.
2. Control manager
Controller manager keeps track of the container cluster objects & resources, thus ensuring that the container’s desired state is consistent.
3. Scheduler
The scheduler schedules the compute request on the cluster. It also looks for unscheduled pods and binds to nodes so that they don’t remain idle.
4. etcd
An open-source distributed key-value store in which Kubernetes holds the cluster data. It is used for configuration management, service discovery, and coordinating distributed work.
Worker node
The worker node provides the container runtime for your app and has the following components:
1. Kubelet
Kubelet communicates with the master and ensures that containers are running on the node.
2. Kube-proxy
Kube-proxy allows the container cluster to forward traffic to execute containers.
3. Docker (container runtime)
Docker offers the runtime environment for containers.
Kubernetes Objects
Pod: A group of one or more containers.
Service: Service works with a set of pods and directs traffic towards them.
Deployment: Ensures that the desired state and scale are maintained.
How containerization using Docker & Kubernetes helps?
Containerization using Docker and Kubernetes helps Softobiz deliver products faster, consistently, and in a predictable manner. We no longer have to worry about the shared dependency conflict. Instead, we pack an app and its dependencies in a container and launch it right away.
This leaves us with a lot of time to focus on developing new features for your product and fixing bugs faster. Releasing new updates and deploying features also become a lot easier.
This way, with tools like Docker and Kubernetes, we can help you deliver a refined product that effectively meets your needs.
Get familiar with different ways to use Kubernetes for enterprise application development.
