What is a Kubernetes Cluster?

As the name implies, a Kubernetes cluster is an open-source tool for controlling, launching, and growing containerized apps. The containerized applications can be managed across multiple computers, and the underlying infrastructure is flexible and scalable, making it easy to build, launch, and handle modern apps. You can run container based applications using Kubernetes on both physical machines and virtual machines. Organizations of all sizes widely adopt Kubernetes, which has become the de facto standard for container orchestration.

Read more about Docker vs Kubernetes, and which one is right for you.

Individual components of an application, including code snippets and the dependencies connected to them, are often packaged inside these containers. For example, suppose inconsistencies are discovered inside a container. 

In this case, it is Kubernetes’ duty to remedy the situation as soon as possible by exchanging the problematic components with ones that are operational. Or, if a certain application sees severe traffic surges that are above its ability to handle, Kubernetes will take the necessary steps to deploy and manage more containers in a seamless manner. 

The Key Components of the Kubernetes Cluster

Kubernetes’ flexibility is attributed to the three components that make up the platform; the Master node, the Worker node, and Addons. For you to successfully deploy a cluster on Kubernetes, these components need to work together harmoniously.

The Master Components

Let’s start by looking at the Master component. The Master component runs a subset of applications on the Master node, and they are the backbone of the cluster, making decisions on server arrangements and more. These applications are the API server, etcd, scheduler, controller manager, and cloud controller manager.

API Servers: API Servers are installed applications that expose Kubernetes through the use of APIs. The Kubernetes CLI, also known as “kubectl,” communicates with containers running the Kubernetes cluster management software and allows you to connect to data through the API Server.

The ETCD: The ETCD is an integral key-value store database where all of the Kubernetes data is kept.

The Scheduler: The Scheduler is one of the node machines responsible for keeping an eye out for pods and assigning them to nodes with sufficient resources to support their operation.

Controller Manager: This component is a single binary that is made up of the four different sub processes below:

  • The node controller is in charge of ensuring that all of the cluster’s nodes are in good health.
  • The replication controller is the component that is accountable for ensuring that each replication maintains the specified number of pods.
  • The endpoints controller is responsible for managing the Endpoints object, which is what connects pods and services.
  • Handling both default account management and API access for namespaces is the responsibility of the service account and token controller.

Worker Node Components

Unlike the Master node component, the worker node component runs with only three sub components. The worker node file system depends on the Kubelet, the proxy, and the container runtime.

The Kubelet: The Kubelet is an agent that operates inside each node controller to guarantee that pods are operating correctly and in a manner that facilitates communication between the Master and the nodes.

The Proxy: The proxy works and runs every node inside a cluster. It is responsible for managing the networking rules within the node.

The Container Runtime: The Container Runtime manages all the standalone containers, including retrieving container images, configuration files from repositories or registries, building blocks, unpacking them, and running the application.

The Addons

To get Kubernetes up and running, you will inevitably require some add-ons. With Kubernetes services, these addons and cluster levels can be deployed using the Kubernetes resources, which are DaemonSet and Deployments. These components cover areas like networking, DNS, metrics, logging, and more.

The Difference Between Cluster and Node Controllers in Kubernetes

Nodes (also known as dedicated servers or virtual machines) usually work together in groups. These groups are called clusters. A Kubernetes cluster contains a set of nodes and the Kubernetes application automatically distributes workloads among these nodes, enabling seamless scaling and resource utilization.

A Kubernetes node is either a virtual or physical machine on which one or more Kubernetes pods runs. It is a worker machine containing the necessary services to run pods, including the CPU and memory resources they need.

Key Points

Kubernetes cluster hosting helps server administrators manage and organize an entire cluster of computer applications. It ensures these applications run smoothly, even if some crash or need more resources.

The ServerMania Cloud supports Kubernetes clusters, among other containerized applications. If this solution is something you require, or if you need more information about cloud deployments or containerization, we’re here to help.

Visit our Knowledge Base for detailed tutorials an guides on how best to deploy your servers or applications. We want to ensure you have the best server cluster hosting infrastructure for your Kubernetes Cluster. Get in touch with us today for a free consultation.