An Introduction to Kubernetes | Developer.com

In light of the widespread adoption of DevOps philosophy, infrastructures that can be rapidly developed, scaled, and secured are becoming increasingly crucial and a norm. Known as k8s, Kubernetes was initially created by Google and has grown to become the de facto standard for controlling applications deployed in containers.

Increasingly, developers are using Kubernetes to improve their workflow and minimize the time spent managing their infrastructure. This software development tutorial talks about Kubernetes, its features and benefits, the control plane, and its components.

You can read more about DevOps and DevSecOps tools by reading our article: Best DevOps and DevSecOps Tools.

What is Kubernetes?

The Kubernetes platform automates container deployments, scalability, and management. You can package your code and dependencies in a container for easy horizontal scaling, portability, and resiliency.

However, managing containers manually can be difficult, as they are ephemeral by nature – once you start one up it will automatically go away when your program crashes or someone kills it. Kubernetes solves this problem by running your application on its own cluster in order to make sure that it always stays up even if there is an error somewhere along the way.

Kubernetes, commonly known as K8s, is an open-source, de facto container orchestration engine and a cloud-agnostic platform for orchestrating containers. It automates container scaling, deployment, and administration containers, which are systems that execute virtualized applications.

You can use Kubernetes not only with Docker, but also with other container runtimes. It abstracts containerized applications’ scheduling, control, and management over cluster resources. Kubernetes allows you to install, execute, and manage cloud-native applications such as Node.js, web services, and mobile apps.

Interested in learning more about Docker? Our sister site, TechRepublic, has a great Docker Cheat Sheet that covers the topic nicely.

What are Containers?

A container allows developers and programmers to separate each application into its process, allowing you to run them more efficiently. Containerized workloads consist of application code, libraries, services, and databases that can execute independently. Kubernetes enables coders to run and manage containerized workloads by automating application containers’ deployment, scaling, and administration.

The use of containers aids in the packaging and distribution of software. A container is just a packaged version of your application; programmers will need a management unit to scale these containers. It is also necessary to manage updates and rollbacks on these containers to ensure they are always up-to-date.

What are the Features and Benefits of Kubernetes?

Below is a list of the features and benefits of Kubernetes for developers and software development teams:

• Automated Deployment: Kubernetes enables consistent, declarative automation across the lifecycle of your application. It allows you to automate deployment, scaling, management, and administration of containerized apps. It also helps improve the efficiency of your operations and development teams.
• Load Balancing: One of the most common applications of Kubernetes is to uniformly distribute the incoming traffic load to all containers and services. This helps to lessen the strain on individual containers while at the same time effortlessly handling massive volumes of traffic.
• Simplified DevOps: Kubernetes embraces the concept of GitOps, in which a git repository serves as the main source of truth for application deployment. If the current deployment and the git history differ, Kubernetes will immediately update the deployment to reflect the current git status.
  You merely need to update the git history with the required modifications, and Kubernetes will automatically update your application. With Kubernetes, it is straightforward to allocate and deallocate resources; you do not need to set up another computer manually. All you have to do now is provide one more node using the Kubernetes interface, and you are all together.
• Simplified Deployment: Kubernetes significantly simplifies the development, release, and deployment processes: it allows container integration and streamlines the management of access to storage resources from several providers.
• Improved Productivity: One of the most significant benefits of using Kubernetes is the ability to build applications faster. Kubernetes enables you to quickly build self-service Platform-as-a-Service apps that incorporate a layer of hardware abstraction. This layer allows developers to roll out changes quickly and manage all nodes as one entity using the Kubernetes engine.
• Lower Costs: In addition, Kubernetes can help you reduce your infrastructure costs. Kubernetes can help enterprises save time and money while maintaining scalability via dynamic and intelligent container administration across many environments.
  Resource allocation can be automatically adjusted to meet the application’s needs. Low-level manual operations on the infrastructure are reduced, thanks to native autoscaling logics (HPA, VPA), and integrations with cloud vendors that allow for dynamic provisioning of resources.
• Scalability: Kubernetes is inherently scalable – it can handle millions of requests and hundreds of thousands of containers across dozens of nodes with ease.
• Security: Kubernetes is built with security in mind and has built-in security features such as logging, access control, and auditing.
• Continuous delivery: Continuous delivery deals with delivering applications to be available 24/7, with minimal downtime. With continuous delivery, you can deploy new versions of your application with little to no human intervention and then automatically scale these applications when required. Kubernetes can quickly host modern distributed cloud-hosted applications and solve many CI/CD issues.

Read: Continuous Testing for DevOps

What is The Kubernetes Control Plane?

Kubernetes Control Plane is also called Master Node, and it is responsible for governing the worker nodes. It ensures that the system is operational and functioning correctly. For administrators and users, it is a primary point of contact for managing cluster nodes.

The Control Plane manages a cluster of machines and ensures that each node is healthy, in communication with its peers, and has the latest information about workloads running on top of it. The Kubernetes control plane is the core of any Kubernetes cluster that handles the scheduling and management of resources in the cluster and is responsible for maintaining the state of objects (e.g., pods, services).

The core functions of the control plane include:

• Scheduling: determining which nodes should run which containers
• Replication controllers: coordinating automatic scaling up or down of pods as necessary based on resource demand from other pods or outside requests (such as from an API)
• StatefulSet controller: manages persistent volumes and persistent volume claims (PVCs)

The Kubernetes control plane consists of the following components:

• etcd – In a Kubernetes cluster, this component stores configuration data and makes it accessible to all nodes.
• kube-controller-manager – This is a component that monitors the state of a cluster.
• kube-apiserver – This represents a REST-based interface that manages and controls all administration and operational activities. The API server is responsible for accepting incoming requests from the clients and then forwarding those requests to the relevant service endpoints. It also acts as an intermediary between client requests and worker nodes for workload scheduling purposes.
• kube-scheduler – The scheduler is responsible for scheduling cluster workloads and determining which pods should run on which nodes at any given time based on resource availability, priorities, or other factors.
• Kubelet – The Kubelet receives instructions from its master via a command-line interface (CLI), such as when new pods are launched or terminated; then relays those instructions into action by communicating with Docker containers directly.

Final Thoughts on Kubernetes and Containerized Programming

In recent years, the use of containers has increased rapidly, requiring an efficient and standardized method of managing these types of applications. Kubernetes was developed as a framework for automating containerized application deployment, scaling, administration, and maintenance.

It has rapidly emerged as the preferred solution for delivering and managing containerized workloads and services. Kubernetes has a vast and fast expanding ecosystem and offers a wealth of functionality for deploying, scaling, and managing containerized applications and services. With Kubernetes, you can declaratively build, deploy, and scale complicated applications much faster than with traditional methods.

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