What is Kubernetes?

Kubernetes is an open-source container orchestration platform originally developed by Google. It provides a framework for automating the deployment, scaling, and management of containerized applications. Kubernetes allows users to manage and coordinate containers across a cluster of machines, providing a highly scalable and resilient infrastructure for running distributed applications.

Developed for in-house use by Google engineers, it was offered outside the company as an open-source system in 2014. Since then, it has experienced widespread adoption and has become an essential part of the cloud-native ecosystem. Kubernetes, along with containers, is widely recognized as the fundamental building block of contemporary cloud applications and infrastructure.

Kubernetes runs on a wide range of infrastructure - including hybrid cloud environments, public cloud, private clouds, virtual machines, and bare metal servers - giving IT teams excellent flexibility.

How does Kubernetes work?

Several main components make up the Kubernetes architecture. They are:

Clusters and nodes

As the building blocks of Kubernetes, clusters are made up of physical or virtual compute machines called nodes. A single master node operates as the cluster’s control plane and manages, for example, which applications are running at any one time and which container images are used. It does this by running a scheduler service that automates container deployment based on developer-defined requirements and other factors.

Multiple worker nodes are responsible for running, deploying, and managing workloads and containerized applications. The worker nodes include the container management tools the organization has chosen, such as Docker, as well as a Kubelet, which is a software agent that receives orders from the master node and executes them.

Clusters can include nodes that span an organization’s entire architecture, from on-premise to public and private clouds to hybrid cloud environments. This is part of the reason Kubernetes can be such an integral component in cloud-native architectures. The system is ideal for hosting cloud-native apps that need to scale rapidly.

Containers

Containers are a lightweight and portable software packaging technology used for deploying and running applications consistently across different computing environments. A container is a standalone executable unit that encapsulates an application along with all its dependencies, including libraries, frameworks, and runtime environments.

Containers provide a way to isolate applications from the underlying infrastructure, ensuring that they run consistently regardless of the host system. This isolation is achieved through containerization technologies like Docker, which use operating system-level virtualization to create isolated environments called containers.

Pods

Pods are the smallest unit of scalability in Kubernetes. They are groups of containers that share the same network and compute resources. Grouping containers together is beneficial because if a specific container is receiving too much traffic, Kubernetes automatically creates a replica of that pod in other nodes in the cluster to spread out the workload.

How it all works together

The Kubernetes platform runs on top of the system’s OS (typically Linux) and communicates with pods operating on the nodes. Using a command-line interface called kubectl, an admin or DevOps user enters the desired state of a cluster, which can include which apps should be running, with which images and resources, and other details.

The cluster’s master node receives these commands and transmits them to the worker nodes. The platform is able to determine automatically which node in the cluster is the best option to carry out the command. The platform then assigns resources and the specific pods in the node that will complete the requested operation.

Kubernetes doesn’t change the basic processes of managing containers, it simply automates them and takes over part of the work so admin and DevOps teams can achieve a high level of control without having to manage every node or container separately. Human teams simply configure the Kubernetes system and define the elements within them. Kubernetes takes on all the actual container orchestration work.

Features and capabilities of Kubernetes

Kubernetes has a good range of features and capabilities that simplify container orchestration across multiple nodes, enable automation of cluster management, and optimize resource utilization. These include:

• Automatic scaling – scale containers and their resources up or down as needed based on usage
• Lifecycle management – allows admin to pause and continue deployments as well as roll back to previous versions
• Desired state declaration – admins define what they need and Kubernetes makes it happen
• Self-healing and resiliency – includes automatic restarts, placements, replication, and scaling
• Scalable storage – admins can dynamically add storage as needed
• Load balancing – the system uses a number of tools to balance loads internally and externally
• Support for DevSecOps – helps simplify container operations security across the container lifecycle and clouds and allows teams to get secure apps to market faster

What is Kubernetes used for?

Kubernetes helps organizations better manage their most complex applications and make the most of existing resources. It also helps ensure application availability and greatly reduces downtime. Through container orchestration, the platform automates many tasks, including application deployment, rollouts, service discovery, storage provisioning, load balancing, auto-scaling, and self-healing. This takes a lot of the management burden off the shoulders of IT or DevOps teams.

Here’s an example: Say a container fails. To keep downtime to a minimum (or eliminate it altogether), Kubernetes can detect the container failure and automatically execute a changeover by restarting, replacing, and/or deleting failed containers. The system also oversees all clusters and determines where to best run containers depending on where and how resources are already being consumed. All of this work happens automatically and within milliseconds – no human team can match that.

What is Kubernetes as a Service?

Kubernetes as a Service (KaaS) is a cloud-based offering that provides managed Kubernetes clusters to users. It allows organizations to leverage the power of Kubernetes without the need for extensive setup and maintenance of the underlying infrastructure. With KaaS, users can focus more on deploying and managing their applications rather than dealing with the complexities of Kubernetes cluster management.

KaaS providers handle tasks such as cluster provisioning, scaling, upgrades, and monitoring, relieving users from the operational burden. They offer user-friendly interfaces or APIs to interact with the Kubernetes clusters and often provide additional features like load balancing, automatic scaling, and integrated logging and monitoring.

By offering Kubernetes as a Service, cloud providers and managed service providers enable developers and organizations to quickly and easily deploy and manage containerized applications at scale, leveraging the benefits of Kubernetes without the need for extensive Kubernetes expertise or infrastructure management skills.

What is Docker?

Like Kubernetes, Docker is an open-source solution that allows users to automate application deployment. Unlike Kubernetes, it’s also a container file format, and has become the de facto file format for Linux containers. Using the Docker Engine, you can build and run containers in a development environment. A container registry such as Docker Hub allows you to share and store container images. The Docker suite of solutions is really good at helping you deploy and run individual containers.

Kubernetes vs Docker

Kubernetes and Docker are two distinct but complementary technologies that are often used together in modern container-based application deployments. Here's a comparison of Kubernetes and Docker:

Docker:

• Docker is a platform and toolset for building and running containers. It provides the ability to package applications and their dependencies into lightweight, isolated containers.

• With Docker, developers can create container images that include everything needed to run an application, such as code, libraries, and runtime environments.

• Docker enables consistent application deployment across different environments, ensuring that applications run reliably regardless of the host system.

• Docker provides an easy-to-use command-line interface (CLI) and a robust ecosystem of tools and services to manage containers.

Kubernetes:

• Kubernetes, often referred to as K8s, is an open-source container orchestration platform that automates the deployment, scaling, and management of containerized applications.

• Kubernetes provides a framework for running and coordinating containers across a cluster of machines.

• It offers features like automatic scaling, load balancing, service discovery, and self-healing capabilities.

• Kubernetes allows for declarative configuration and scaling, making it easier to manage complex application deployments.

• It provides a high level of fault tolerance and resilience by ensuring that applications are always running and available, even in the event of failures.

In summary, Docker is primarily focused on building and packaging containers, while Kubernetes focuses on orchestrating and managing containers at scale. Docker provides the tools to create and run containers, while Kubernetes provides the infrastructure to deploy and manage containerized applications in a distributed environment. It's common to use Docker to build container images and then use Kubernetes to manage and orchestrate those containers across a cluster of machines.

Benefits of Kubernetes

Kubernetes offers a wide range of benefits, especially to those organizations that are focusing on cloud-native applications. The following benefits are just part of the reason Kubernetes is far and away the most popular container management system available today: 

• Move workloads wherever they operate best – the platform’s ability to run on-premises and in the cloud make it simple.
• Simplify monitoring, managing, deploying, and configuring containerized apps of any size or scale.
• Integrate Kubernetes easily into existing architecture with its high extensibility.
• Keep IT spending under control through Kubernetes’ built-in resource optimization, ability to run workloads anywhere, and automatic scalability based on demand.
• Free up IT and DevOps teams to focus on more critical tasks instead of managing and orchestrating containerized apps.
• Optimize hardware resource usage, including network bandwidth, memory, and storage I/O, with the ability to define usage limits.
• Increase application efficiency and uptime with Kubernetes’ self-healing features.
• Schedule software updates without causing downtime.
• Future-proof your infrastructure with Kubernetes’ ability to run on decoupled architectures and handle quick and massive growth.