Kubernetes

Guide Kubernetes 2022

With containers you can utilize the true potential of servers, still, companies face some challenges. There is a myth that deploying more containers can help businesses grow, but it doesn’t always help.

Why?

When a business witnesses variation in traffic, it requires an automated way to adapt to the changes. But traditional ways to encounter such situations lead to either increase in cost (consistent server usage even in low traffic) or the application’s unavailability (sudden increase in traffic collapses server).

In simple words, containers help deploy and scale applications easily, but they also bring complexity and challenges unless you use container orchestration tools like Kubernetes.

What Is Kubernetes?

Kubernetes, or k8s, is an open-source platform that automates Linux container operations. It eliminates many of the manual processes involved in deploying and scaling containerized applications. - Click to Tweet.

In other words, you can cluster together groups of hosts running Linux containers, and Kubernetes helps you easily and efficiently manage those clusters.

How Does Kubernetes Work?

Cluster is the central component of the Kubernetes. In a cluster, among many virtual machines or physical machines, each machine either works as a master or as a node. While each node hosts groups of one or more containers, the master dictates conditions to nodes about creating or destroying the containers. Plus, the master tells the node how to re-route traffic based on new container alignments.

Components of Kubernetes:

• Kubernetes Master Components:
  1. etcd: The state and configuration data for the entire cluster is stored by the master in the etcd. It is a distributed key-value data store that each node accesses and uses to manage the configuration of the containers. However, etcd can be run on Kubernetes master or standalone configurations.
  2. Kube API Server: With the help of the Kube API server, the Master communicates with the rest of the cluster. It is the main access point to the control plane that ensures etcd configurations match with the configuration of the container in the cluster.
  3. Kube Controller Manager: It manages the control loop to manage the state of the cluster using the Kubernetes API server.
  4. Kube Scheduler: This service is responsible for tracking and managing the node workloads in the cluster. It monitors the capacity and resources of the nodes and based on this information assign the work to nodes.
  5. Cloud Controller Manager: It works as an abstraction layer between the APIs and tools of a Cloud provider and their representational counterparts in Kubernetes.
• Kubernetes Nodes Components:
  1. Kubelet: It’s an agent process that lets each Kubernetes node run. This process manages the state of the node like starting, stopping, and maintaining application containers based on the instruction received from the control plane. Kubelet gathers performance and health information from the nodes, pods, and containers to run and share the information with the control plane so that the control plane can make scheduling decisions.
  2. Kube Proxy: It’s a network proxy that runs on the cluster nodes. It functions as a load balancer for services running on the node.
  3. Pod: It’s the basic scheduling unit that comprises one or more containers to be co-located on a host machine to share resources. Each pod is assigned a unique IP address within the cluster, thus applications can use ports without conflict.

Kubernetes Tools:

• Kubectl: It’s a command-line tool that helps you run commands against Kubernetes clusters. With Kubectl you can deploy applications, inspect and manage cluster resources, and view logs.
• Minikube: Using Minikube you can run Kubernetes locally. It runs a single-node Kubernetes cluster on your personal computer ( Windows, macOS, and Linux) either to try out Kubernetes or to do daily development work.

Advantages of Kubernetes:

• Ensures 24/7 Availability of Applications and Services: A container orchestrator tool like Kubernetes helps you schedule processes across many machines multiple times and process your applications without any disruption even if you lose a node.
• Eases Deployment of Code Multiple Times a Day With No Downtime: Kubernetes helps system operators and developers to deploy code multiple times a day by incorporating smart processes and schemes to roll out updates with no downtime.
• Assures Efficient Use of Cloud Resources: Kubernetes offers elasticity to use your cloud resources efficiently. It recognizes the usage of cloud resources when they are idle and need to be spun down. Also, it lets you process many processes on a single cloud node rather than a single process on a single cloud node.
• Automates Horizontal Scaling in the Node and Container: Kubernetes brings new nodes and automatically adds them to your cluster when a single service seems resource-constrained. Kubernetes detects these instances and adds resources to handle such additional load.

How Did Kubernetes Help BlaBlaCar in Growing Its Services?

When BlaBlaCar, a ride-sharing company in France, experienced exponential growth the company needed to upgrade its servers. But they didn’t want to hire more people to manage servers and installations. However, they were reluctant to give a try to the virtual servers, and in the end, chose bare metal servers. Prior to using containers, in order to roll out a new service, they had to launch a new server.

To utilize containers in a better way, it needed an orchestration tool so they switched to Kubernetes. Now, to create a new service all they need is a few minutes compared to a day or sometimes two in the past. With the help of Kubernetes, they can take maximum advantage of containerization. For instance, if a server fails because of a hardware failure, containers can be moved to a new server by changing a line in the configuration file. And that too happens automatically. This process has not only increased the uptime but also has reduced the hassles.

Kubernetes vs. Docker: Differences

There is a common misconception among the people that Kubernetes and Docker are the adversaries. Well, they are not and there is no similarity between the two. However, you should know why there are such rumors prevailing.

Docker is a container-building tool.And Kubernetes is a container orchestration tool yet it’s not the only container orchestration tool available in the market. Docker Swarm is the rival of the Kubernetes.

Since Docker Swarm is built by Docker Inc., people get confused between Docker Swarm (container orchestration tool) and Docker(container builder tool). Nevertheless, if you’ve read so far, you would not want to miss the difference between the rivals that we have included in the following table.

Basis of Comparison	Kubernetes	Docker Swarm
Functioning	The basic unit of Kubernetes is the pod that is composed of one or more containers located on the host machine so they can share resources.	Cluster, the basic unit of Swarm, is a group of machines running Docker together.
Installation	Kubernetes installation is complex as it requires several steps to follow.	The installation process is simple as Swarm requires only two commands.
Container Setup	You can’t use Docker’s command-line interface to define Docker containers as it uses its language(YAML), API, and client definitions.	It offers a wide range of functions, still, its APL doesn’t let you explore all the Docker commands.
Load Balancing	To balance the load you will need to configure the pod manually.	With Swarm, automatic load balancing is possible if all nodes are connected to the group.

Conclusion

Containers have made the deployment of applications easier but they do not ensure optimum utilization of resources. Kubernetes is the perfect solution for those who want to make the best use of their available resources while keeping their applications up and running with lesser troubles. And the best part is that developers can roll out new features instead of worrying about the availability of resources.