Understanding Kubernetes – A Guide to Modernizing Your Cloud Infrastructure 2025

Kubernetes allows developers of containerized applications—like those created with Docker—to develop more reliable infrastructure, a critical need for applications and platforms that need to respond to events like rapid spikes in traffic or the need to restart failed services.

Nowadays, all Server SDKs(face recognition, face liveness detection, ID card recognition, ID document liveness, etc) released by KBY-AI are compatible with Kubernetes clusters, including EKS.

Kubernetes is quickly becoming the new industry-standard tool for running cloud-native applications. As more developers and organizations move away from on-premises infrastructure to take advantage of the cloud, advanced management is needed to ensure high availability and scalability for containerized applications. To build and maintain applications, you need to coordinate resources across different machine types, networks, and environments.

Kubernetes allows developers of containerized applications—like those created with Docker—to develop more reliable infrastructure, a critical need for applications and platforms that need to respond to events like rapid spikes in traffic or the need to restart failed services. With Kubernetes, you can now delegate events that would require the manual intervention of an on-call developer.

Kubernetes (K8s) optimizes container orchestration deployment and management for cloud infrastructure by creating groups, or Pods, of containers that scale without writing additional lines of code and responding to the needs of the application. Key benefits of moving to container-centric infrastructure with Kubernetes is knowing that infrastructure will self-heal and that there will be environmental consistency from development through to production.

What is Kubernetes

Kubernetes is a container orchestration system that was initially designed by Google to help scale containerized applications in the cloud. Kubernetes can manage the lifecycle of containers, creating and destroying them depending on the needs of the application, as well as providing a host of other features.

Kubernetes has become one of the most discussed concepts in cloud-based application development, and the rise of Kubernetes signals a shift in the way that applications are developed and deployed.

In general, Kubernetes is formed by a cluster of servers, called Nodes, each running Kubernetes agent processes and communicating with one another. The Master Node contains a collection of processes called the control plane that helps enact and maintain the desired state of the Kubernetes cluster, while Worker Nodes are responsible for running the containers that form your applications and services.

CONTAINERS

Kubernetes is a container orchestration tool and, therefore, needs a container runtime installed to work. In practice, the default container runtime for Kubernetes is Docker, though other runtimes like rkt, and LXD will also work. With the advent of the Container Runtime Interface (CRI), which hopes to standardize the way Kubernetes interacts with containers, other options like containerd, cri-o, and Frakti are also available. Examples throughout this guide will use Docker as the container runtime.

• Containers are similar to virtual machines. They are light-weight isolated runtimes that share resources of the operating system without having to run a full operating system themselves. Containers consume few resources but contain a complete set of information needed to execute their contained application images such as files, environment variables, and libraries.
• Containerization is a virtualization method to run distributed applications in containers using microservices. Containerizing an application requires a base image to create an instance of a container. Once an application’s image exists, you can push it to a centralized container registry that Kubernetes can use to deploy container instances in a cluster’s pods, which you can learn more about in “Beginner’s Guide to Kubernetes: Objects“.
• Orchestration is the automated configuration, coordination, and management of computer systems, software, middleware, and services. It takes advantage of automated tasks to execute
  processes. For Kubernetes, container orchestration automates all the provisioning, deployment, and availability of containers; load balancing; resource allocation between containers; and health monitoring of the cluster.

KUBERNETES API

Kubernetes is built around a robust RESTful API. Every action taken in Kubernetes—be it inter-component communication or user command—interacts in some fashion with the Kubernetes API. The goal of the API is to help facilitate the desired state of the Kubernetes cluster. The Kubernetes API is a “declarative model,” meaning that it focuses on the what, not the how. You tell it what you want to accomplish, and it does it. This might involve creating or destroying resources, but you don’t have to worry about those details. To create this desired state, you create objects, which are normally represented by YAML files called manifests, and apply them through the command line with the kubectl tool.

KUBECTL

kubectl is a command line tool used to interact with the Kubernetes cluster. It offers a host of features, including the ability to create, stop, and delete resources; describe active resources; and auto scale resources. For more information on the types of commands and resources, you can use with kubectl, consult the Kubernetes kubectl documentation.

Master, Nodes, and the Control Plane

At the highest level of Kubernetes, there exist two kinds of servers, a Master and a Node. These servers can be Linodes, VMs, or physical servers. Together, these servers form a cluster controlled by the services that make up the Control Plane.

For your Kuberentes cluster to maintain homeostasis for your application, it requires a central source of communications and commands. Your Kubernetes Master, Nodes, and Control Plane are the essential components that run and maintain your cluster. The Control Plane refers to the functions that make decisions about cluster maintenance, whereas the Master is what you interact with on the command-line interface to assess your cluster’s state.

KUBERNETES MASTER

The Kubernetes Master is normally a separate server responsible for maintaining the desired state of the cluster. It does this by telling the Nodes how many instances of your application it should run and where.

NODES

Kubernetes Nodes are worker servers that run your application(s). The user creates and determines the number of Nodes. In addition to running your application, each Node runs two processes:

• kubelet receives descriptions of the desired state of a Pod from the API server, and ensures the Pod is healthy, and running on the Node.
• kube-proxy is a networking proxy that proxies the UDP, TCP, and SCTP networking of each Node, and provides load balancing. kube-proxy is only used to connect to Services.

THE CONTROL PLANE

Together, kube-apiserver, kube-controller-manager, kube-scheduler, and etcd form what is known as the control plane. The control plane is responsible for making decisions about the cluster and pushing it toward the desired state. kube-apiserver, kube-controller-manager, and kube-scheduler are processes, and etcd is a database; the Kubernetes Master runs all four.

• kube-apiserver is the front end for the Kubernetes API server.
• kube-controller-manager is a daemon that manages the Kubernetes control loop. For more on Controllers, see the Beginner’s Guide to Kubernetes: Controllers.
• kube-scheduler is a function that looks for newly created Pods that have no Nodes, and assigns them a Node based on a host of requirements. For more information on kube-scheduler, consult the Kubernetes kube-scheduler documentation.
• Etcd is a highly available key-value store that provides the backend database for Kubernetes. It stores and replicates the entirety of the Kubernetes cluster state. It’s written in Go and uses the Raft protocol, which means it maintains identical logs of state-changing commands across nodes and coordinates the order in which these state changes occur.

Objects

In Kubernetes, there are a number of objects that are abstractions of your Kubernetes system’s desired state. These objects represent your application, its networking, and disk resources–all of which together form your application. In the Kubernetes API, four basic Kubernetes objects: Pods, Services, Volumes, and Namespaces represent the abstractions that communicate what your cluster is doing. These objects describe what containerized applications are running, the nodes they are running on, available resources, and more.

PODS

In Kubernetes, all containers exist within Pods. Pods are the smallest unit of the Kubernetes architecture. You can view them as a kind of wrapper for your container. Each Pod gets its own IP address with which it can interact with other Pods within the cluster. Usually, a Pod contains only one container, but a Pod can contain multiple containers if those containers need to share resources.

If there is more than one container in a Pod, these containers can communicate with one another via localhost. Pods in Kubernetes are “mortal,” which means they are created and destroyed depending on the needs of the application. For instance, you might have a web app backend that sees a spike in CPU usage.

This situation might cause the cluster to scale up the number of backend Pods from two to ten, in which case eight new Pods would be created. Once the traffic subsides, the Pods might scale back to two, in which case eight pods would be destroyed. It is important to note that Pods get destroyed without respect to which Pod was created first. And, while each Pod has its own IP address, this IP address will only be available for the lifecycle of the Pod.KUBERNETES MASTER

Here is an example of a Pod manifest:

SERVICES

Services group identical Pods together to provide a consistent means of accessing them. For instance, you might have three Pods that are all serving a website, and all of those Pods need to be accessible on port 80. A Service can ensure that all of the Pods are accessible at that port, and can load balance traffic between those Pods.
Additionally, a Service can allow your application to be accessible from the internet. Each Service gets an IP address and a corresponding local DNS entry. Additionally, Services exist across Nodes. If you have two replica Pods on one Node and an additional replica Pod on another Node, the Service can include all three Pods.

There are four types of Services:

• ClusterIP: Exposes the Service internally to the cluster. This is the default setting for a Service.
• NodePort: Exposes the Service to the internet from the IP address of the Node at the specified port number. You can only use ports in the 30000-32767 range.
• LoadBalancer: This will create a load balancer assigned to a fixed IP address in the cloud, so long as the cloud provider supports it. In the case of Linode, this is the responsibility of the Linode Cloud Controller Manager, which will create a NodeBalancer for the cluster. This is the best way to expose your cluster to the internet.
• ExternalName: Maps the service to a DNS name by returning a CNAME record redirect. ExternalName is good for directing traffic to outside resources, such as a database that is hosted on another cloud.

Here is an example of a Service manifest that uses the v1 API:

Like the Pod example in the previous section, this manifest has a name and a label. Unlike the Pod example, this spec uses the ports field to define the exposed port on the container (port), and the target port on the Pod (targetPort). The type NodePort unlocks the use of nodePort field, which allows traffic on the host Node at that port. Lastly, the selector field targets only the Pods assigned the app: web label.

VOLUMES

A Volume in Kubernetes is a way to share file storage between containers in a Pod. Kubernetes Volumes differ from Docker volumes because they exist inside the Pod rather than inside the container. When a container gets restarted, the Volume persists. Note, however, that these Volumes are still tied to the lifecycle of the Pod, so if the Pod gets destroyed, the Volume gets destroyed with it. Linode also offers a Container Storage Interface (CSI) driver that allows the cluster to persist data on a Block Storage volume.

Here is an example of how to create and use a Volume by creating a Pod manifest:

A Volume has two unique aspects to its definition. In this example, the first aspect is the volumes block that defines the type of Volume you want to create, which in this case is a simple empty directory (emptyDir). The second aspect is the volumeMounts field within the container’s spec. This field is given the name of the Volume you are creating and a mount path within the container. There are a number of different Volume types you could create in addition to emptyDir depending on your cloud host.

NAMESPACES

Namespaces are virtual clusters that exist within the Kubernetes cluster that help to group and organize objects. Every cluster has at least three namespaces: default, kube-system, and kube-public. When interacting with the cluster it is important to know which Namespace the object you are looking for is in as many commands will default to only showing you what exists in the default namespace. Resources created without an explicit namespace will be added to the default namespace.

A Controller is a control loop that continuously watches the Kubernetes API and tries to manage the desired state of certain aspects of the cluster. Here are short references of the most popular controllers.

DEPLOYMENTS

A Deployment can keep a defined number of replica Pods up and running. A Deployment can also update those Pods to resemble the desired state by means of rolling updates. For example, if you want to update a container image to a newer version, you would create a Deployment. The controller would update the container images one by one until the desired state is achieved, ensuring that there is no downtime when updating or altering your Pods.

Here is an example of a Deployment:

Namespaces consist of alphanumeric characters, dashes (-), and periods (.).

In this example, the number of replica Pods is set to five, meaning the Deployment will attempt to maintain five of a certain Pod at any given time. A Deployment chooses which Pods to include by use of the selector field. In this example, the selector mode is matchLabels, which instructs the Deployment to look for Pods defined with the app: web label.

As you will see, the only noticeable difference between a Deployment’s manifest and that of a ReplicaSet is the kind.

Controllers

REPLICASETS

Note: Kubernetes now recommends the use of Deployments instead of ReplicaSets. Deployments provide declarative updates to Pods, among other features, that allow you to define your application in the spec section. In this way, ReplicaSets have essentially become deprecated.

Kubernetes allows an application to scale horizontally. A ReplicaSet is one of the controllers responsible for keeping a given number of replica Pods running. If one Pod goes down in a ReplicaSet, another gets created to replace it. In this way, Kubernetes is self-healing. However, for most use cases, it is recommended to use a Deployment instead of a ReplicaSet.

There are three important considerations regarding this ReplicaSet. First, the apiVersion (apps/v1) differs from the previous examples, which were apiVersion: v, because ReplicaSets do not exist in the v1 core. They instead reside in the apps group of v1. Also, note the replicas field and the selector field. The replicas field defines how many replica Pods you want to be running at any given time. The selector field defines which Pods, matched by their label, will be controlled by the ReplicaSet.

JOBS

A Job is a controller that manages a Pod created for a single or set of tasks. This is handy if you need to create a Pod that performs a single function or calculates a value. The deletion of the Job will delete the Pod.

Here is an example of a Job that simply prints “Hello World!” and ends:

Networking

Networking in Kubernetes makes it simple to port existing apps from VMs to containers, and subsequently, Pods. The basic requirements of the Kubernetes networking model are:

• Pods can communicate with each other across Nodes without the use of NAT.
• Agents on a Node, like kubelet, can communicate with all of a Node’s Pods.
• In the case of Linux, Pods in a Node’s host network can communicate to all other Pods without NAT.

Though the rules of the Kubernetes networking model are simple, the implementation of those rules is an advanced topic. Because Kubernetes does not come with its own implementation, it is up to the user to provide a networking model.

Two of the most popular options are Flannel and Calico.

• Flannel is a networking overlay that meets the functionality of the Kubernetes networking model by supplying a layer 3 network fabric and is relatively easy to set up.
• Calico enables networking and networking policy through the NetworkPolicy API to provide simple virtual networking.

Our Take

Over the past decade, developers have used containers to both deploy and maintain applications more efficiently. As the use of container engines like Docker continued to grow, it was only a matter of time before developers would need to simplify this process even further. Kubernetes is the result of several years of innovation and advancing best practices to build an orchestrator that streamlines the complexity of containers.

Kubernetes is rapidly evolving. The true impact of Kubernetes as an open source project increases as managed Kubernetes services become more affordable, widely available, and as more third-party integrations give developers the ability to customize their Kubernetes experiences. As the ecosystem continues to advance, developers will expand their use cases for production workloads. Kubernetes is here to stay, and Kubernetes skills will become even more in-demand.

With the emergence of Kubernetes as a widely used tool in cloud computing, it’s critical for developers to find sustainable and affordable managed Kubernetes services. Linode Kubernetes Engine (LKE) is designed to work for developers who are ready to use Kubernetes for production workloads with efficient and affordable resources, as well as developers who are simply exploring how Kubernetes will work for them.

About KBY-AI

KBY-AI‘s mission is to accelerate innovation by providing identity verification server SDKs making cloud computing simple, affordable, and accessible to all.

KBY-AI has uploaded all their server SDKs to Docker Hub to streamline the identity verification process for customers by enabling easier deployment of Kubernetes systems using Docker containers, as previously discussed.

Currently, SDKs for face liveness detection, face recognition, face search, ID document recognition, ID document liveness detection, vehicle license plate recognition, and palmprint recognition are available on Docker Hub. This allows users to easily pull these products and achieve robust back-end performance with Kubernetes deployments.

KBY-AI offers on-premises identity verification solutions with a perpetual license, providing a cost-effective option to help you significantly reduce costs.

Frequently Asked Questions

What is Kubernates?

Kubernetes is a container orchestration system that was initially designed by Google to help scale containerized applications in the cloud.

Can KBY-AI’s identity verification SDK operate on a Kubernetes system?

Yes, their server SDKs can be easily deployed on a Kubernetes system to handle multiple threads simultaneously, enhancing performance.

Where can I find the ideal solution for configuring an EKS cluster for a digital onboarding process?

Simply contact the KBY-AI technical team, which provides free support to all customers, enabling you to innovate your business with powerful solutions.

Why Kubernetes?

Kubernetes is a powerful tool for managing containerized applications. It ensures high availability, scalability, and reliability by automating tasks like deployment, scaling, and self-healing. It also provides consistent environments from development to production, making it easier to handle traffic spikes, failures, and complex cloud infrastructure without writing extra code.

Where can I get powerful customer onboarding solutions?

Just reach out to KBY-AI company, which is powerful identity verification SDK provider.

Conclusion

Kubernetes has become the industry standard for managing containerized applications, offering high availability, scalability, and reliability. By automating the orchestration of containers, Kubernetes ensures self-healing infrastructure and consistent environments across development and production.

This makes it an ideal choice for cloud-native applications, such as KBY-AI’s advanced server SDKs, which are fully compatible with Kubernetes clusters like EKS. For organizations transitioning to the cloud, Kubernetes provides the advanced resource management needed to meet modern application demands efficiently.