Computer cluster

As explained in Road to Kubernetes

A cluster is a group of machines coordinated to run workloads as a shared computing system.

A computer cluster is a group of machines coordinated to run workloads as one shared computing system. In Kubernetes, the machines run Kubernetes and containers; each machine is a node. section 8.1 section 8.1.3

A Kubernetes cluster organizes application execution through related components:

• Container runtimes execute portable application bundles in isolation. section 8.1.3
• Pods provide the smallest running unit, including container configuration and optionally multiple resource-sharing containers. section 8.1.3
• Deployments declare container images and desired Pod replicas, while Services expose Pods internally or externally. section 8.0 section 8.1.3
• Namespaces organize resources by project, environment, organization, or team. section 8.1.3

From machines to an application

Start with virtual machines, install or select Kubernetes, and place them in a cluster. Kubernetes then schedules containers across the nodes, maintains the requested number of instances, and exposes them through a Service; managed Kubernetes avoids maintaining the Kubernetes installation and updates yourself. section 8.0 section 1.6

Figure 8.3 Kubernetes concepts

Use the component map to connect clusters, nodes, containers, Pods, Deployments, Services, and related Kubernetes resources. section 8.1.3

How Road to Kubernetes covers it

How deep it goes

Defines clusters, nodes, Pods, Deployments, and Services, then stops short of exhaustive Kubernetes internals.

Examples

Uses cloud virtual machines, on-premises servers, Raspberry Pis, and repurposed desktops as possible cluster machines.

What it assumes

Assumes containerized applications and introduces cluster components at a high level before practical Kubernetes use.

What you can do after

Operate containerized applications across nodes using Kubernetes clusters, Deployments, and Services.

How it connects

Connects Kubernetes with virtual machines, nodes, containers, Pods, Deployments, Services, namespaces, and container runtimes.

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Also explained in

• 

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  Elasticsearch in Action, Second EditionA cluster is a group of connected computing nodes that operates as a coordinated Elasticsearch system for distributed processing and storage.
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  Kubernetes for DevelopersA cluster is a group of machines managed together as a shared computing resource.
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  ASP.NET Core in Action, 3eClustering is a coordination technique in which multiple application instances distribute work so that a task is executed by only one instance.
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  Starting Data Analytics with Generative AI and PythonA cluster is a group of interconnected computers that operates as a unified system for computational tasks.
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  Effective Data AnalysisA computing cluster is a group of networked computers that jointly execute computational tasks.
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  Build and Orchestrator in Go (From Scratch)A cluster is a coordinated collection of manager and worker machines operated together by an orchestration system.
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  Distributed Machine Learning PatternsA cluster is a group of connected computing machines managed to execute workloads as a coordinated resource.

Compare how 8 books explain computer cluster →

Related concepts

• Kubernetes worker nodehas part · A Kubernetes worker node is a physical or virtual machine in a cluster that provides compute resources and runs scheduled Pods and node-level services.
• kubectlused by · kubectl is the Kubernetes command-line client for communicating with the Kubernetes API and managing cluster resources.
• autoscalingconfigured by · Autoscaling is the automatic adjustment of computing resource capacity or running instances in response to workload demand or measured system conditions.
• nodehas part · A node is a discrete element in a structured system, such as a graph, tree, network, or distributed system, representing an entity, state, component, or computational unit and potentially connected to other elements.
• single-node clusterincludes · A single-node cluster is an Elasticsearch cluster containing one node.

This explainer was generated by Manning's knowledge graph from the text of Road to Kubernetes. The section links point to the parts of the book it draws on.