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Version: 0.12

Glossary

Table of Contents​

A | B | C | F | I | K | M | N | O | P | R | S | T | W

A​

Add-ons​

Services beyond the fundamental components required to deploy a Kubernetes-conformant cluster and categorized into two types:

  • Core Add-ons: Addons that are required to deploy a Kubernetes-conformant cluster: DNS, kube-proxy, CNI.
  • Additional Add-ons: Addons that are not required for a Kubernetes-conformant cluster (e.g. metrics/Heapster, Dashboard).

Air-gapped environment​

Setting up and running Kubernetes clusters without direct access to the internet.

B​

Bootstrap​

The process of turning a server into a Kubernetes node. This may involve assembling data to provide when creating the server that backs the Machine, as well as runtime configuration of the software running on that server.

Bootstrap cluster​

A temporary cluster that is used to provision a Target Management cluster.

Bootstrap provider​

Refers to a provider that implements a solution for the bootstrap process.

C​

CAPI​

Core Cluster API

CAPA​

Cluster API Provider AWS

CAPD​

Cluster API Provider Docker

CAPG​

Cluster API Google Cloud Provider

CAPIO​

Cluster API Operator

CAPRKE2​

Cluster API Provider RKE2

CAPV​

Cluster API Provider vSphere

CAPZ​

Cluster API Provider Azure

CAPI Provider​

A public API that facilitates provisioning and operations over the CAPI Operator and Cluster API resources.

Child Cluster​

Term commonly used interchangeably with the workload cluster.

Cluster​

A full Kubernetes deployment. See Management Cluster and Workload Cluster.

ClusterClass​

A collection of templates that define a topology (control plane and workers) to be used to continuously reconcile one or more Clusters. See ClusterClass

Cluster API​

Or Cluster API project

The Cluster API is a sub-project of the SIG-cluster-lifecycle. It is also used to refer to the software components, APIs, and community that produce them.

See core provider

Cluster API Operator​

Or Cluster API Operator project

The Cluster API Operator is a sub-project of the SIG-cluster-lifecycle. It is designed to empower cluster administrators to handle the lifecycle of Cluster API providers within a management cluster using a declarative approach.

Cluster API Provider RKE2​

Cluster API Provider RKE2 is a combination of two provider types: a Cluster API Control Plane Provider for provisioning Kubernetes control plane nodes and a Cluster API Bootstrap Provider for bootstrapping Kubernetes on a machine where RKE2 is used as the Kubernetes distro.

Control plane​

The set of Kubernetes services that form the basis of a cluster. See also https://kubernetes.io/docs/concepts/#kubernetes-control-plane There are two variants:

  • Self-provisioned: A Kubernetes control plane consisting of pods or machines wholly managed by a single Cluster API deployment.
  • External or Managed: A control plane offered and controlled by some system other than Cluster API (e.g., GKE, AKS, EKS, IKS).

Control plane provider​

Refers to a provider that implements a solution for the management of a Kubernetes control plane.

See CAPRRKE2, KCP.

Core provider​

Refers to a provider that implements Cluster API core controllers; if you consider that the first project that must be deployed in a management Cluster is Cluster API itself, it should be clear why the Cluster API project is also referred to as the core provider.

See CAPI.

F​

Fleet​

A container management and deployment engine designed to offer users more control on the local cluster and constant monitoring through GitOps. Take a look at fleet documentation to know more about Fleet.

I​

Infrastructure provider​

Refers to a provider that implements provisioning of infrastructure/computational resources required by the Cluster or by Machines (e.g. VMs, networking, etc.). Clouds infrastructure providers include AWS, Azure, or Google; while VMware, MAAS, or metal3.io can be defined as bare metal providers.

IPAM provider​

Refers to a provider that allows Cluster API to interact with IPAM solutions. IPAM provider's interaction with Cluster API is based on the IPAddressClaim and IPAddress API types.

K​

Kubernetes-conformant​

Or Kubernetes-compliant

A cluster that passes the Kubernetes conformance tests.

Kubernetes Operator​

A Kubernetes Operator is a method of packaging, deploying, and managing a Kubernetes application. See also https://kubernetes.io/docs/concepts/extend-kubernetes/operator/ for more information.

k/k​

Refers to the main Kubernetes git repository or the main Kubernetes project.

KCP​

Kubeadm Control plane Provider

M​

Machine​

Or Machine Resource

The Custom Resource for Kubernetes that represents an infrastructure component that hosts a Kubernetes node.

Manage a cluster​

Perform create, scale, upgrade, or destroy operations on the cluster.

Managed Kubernetes​

Managed Kubernetes refers to any Kubernetes cluster provisioning and maintenance abstraction, usually exposed as an API, that is natively available in a Cloud provider. For example: EKS, OKE, AKS, GKE, IBM Cloud Kubernetes Service, DOKS, and many more throughout the Kubernetes Cloud Native ecosystem.

Managed Topology​

See Topology

Management cluster​

The cluster where one or more Infrastructure Providers run, and where resources (e.g. Machines) are stored. Typically referred to when you are provisioning multiple workload clusters.

N​

Node pools​

A node pool is a group of nodes within a cluster that all have the same configuration.

O​

Operating system​

Or OS

A generically understood combination of a kernel and system-level userspace interface, such as Linux or Windows, as opposed to a particular distribution.

P​

Pivot​

Pivot is a process for moving the provider components and declared cluster-api resources from a Source Management cluster to a Target Management cluster.

The pivot process is also used for deleting a management cluster and could also be used during an upgrade of the management cluster.

Provider​

Or Cluster API provider

This term was originally used as abbreviation for Infrastructure provider, but currently it is used to refer to any project that can be deployed and provides functionality to the Cluster API management Cluster.

See Bootstrap provider, Control plane provider, Core provider, Infrastructure provider, IPAM provider, Runtime extension provider.

Provider components​

Refers to the YAML artifact published as part of the release process for providers; it usually includes Custom Resource Definitions (CRDs), Deployments (to run the controller manager), RBAC, etc.

In some cases, the same expression is used to refer to the instances of above components deployed in a management cluster.

See Provider repository

Provider repository​

Refers to the location where the YAML for provider components are hosted; usually a provider repository hosts many version of provider components, one for each released version.

R​

Rancher​

An open-source platform designed to simplify the deployment and management of Kubernetes clusters.

Rancher Cluster Agent​

A component deployed by Rancher in each Kubernetes cluster it manages. Its primary role is to establish a secure communication channel between the Rancher server and the Kubernetes cluster, enabling Rancher to manage and interact with the cluster.

Rancher Manager​

The Rancher Manager (or Rancher Server) is where the Rancher UI and API are hosted, and it communicates with managed clusters through components like the Rancher Cluster Agent. It allows users to manage their Kubernetes clusters, applications, and Rancher-specific resources such as Catalogs, Users, Global Roles, and more.

Rancher Turtles​

A Kubernetes operator that provides integration between Rancher Manager and Cluster API (CAPI) with the aim of bringing full CAPI support to Rancher.

RKE2​

Rancher's next-generation, fully conformant Kubernetes distribution that focuses on security and compliance within the U.S. Federal Government sector. See documentation for more details.

Runtime Extension​

An external component which is part of a system built on top of Cluster API that can handle requests for a specific Runtime Hook.

Runtime Extension provider​

Refers to a provider that implements one or more runtime extensions.

S​

Scaling​

Unless otherwise specified, this refers to horizontal scaling.

Stacked control plane​

A control plane node where etcd is colocated with the Kubernetes API server, and is running as a static pod.

Server​

The infrastructure that backs a Machine Resource, typically either a cloud instance, virtual machine, or physical host.

T​

Topology​

A field in the Cluster object spec that allows defining and managing the shape of the Cluster's control plane and worker machines from a single point of control. The Cluster's topology is based on a ClusterClass. Sometimes it is also referred as a managed topology.

See ClusterClass

Turtles​

Refers to Rancher Turtles

W​

Workload Cluster​

A cluster created by a ClusterAPI controller, which is not a bootstrap cluster, and is meant to be used by end-users, as opposed to by CAPI tooling.

WorkerClass​

A collection of templates that define a set of worker nodes in the cluster. A ClusterClass contains zero or more WorkerClass definitions.

See ClusterClass