Cluster API 용어집

1 개요

Table of Contents

2 A

Add-ons

애드온

Kubernetes의 기본 컴포넌트 이상의 서비스

• 코어 애드온: Kubernetes 호환 클러스터를 배포하는 데 필수적인 애드온: DNS, kube-proxy, CNI.
• 추가 애드온: Kubernetes 호환 클러스터에 필수적이지 않은 애드온 (예: 메트릭/힙스터, 대시보드).

3 B

Bootstrap

부트스트랩

서버를 Kubernetes 노드로 전환하는 과정. 여기에는 머신을 지원하는 서버를 생성할 때 제공할 데이터 수집과, 해당 서버에서 실행되는 소프트웨어의 런타임 설정이 포함될 수 있습니다.

Bootstrap cluster

부트스트랩 클러스터

대상 관리 클러스터를 프로비저닝하는 데 사용되는 임시 클러스터.

Bootstrap provider

부트스트랩 제공자

부트스트랩 프로세스에 대한 솔루션을 구현하는 제공자. Bootstrap 제공자와 Cluster API의 상호작용은 Cluster API 계약에 정의된 내용을 기반으로 합니다.

CABPK 참조.

4 C

CAEP

Cluster API Enhancement Proposal - patterned after KEP. See template

CAPI

Core Cluster API

CAPA

Cluster API Provider AWS

CABPK

Cluster API Bootstrap Provider Kubeadm

CABPOCNE

Cluster API Bootstrap Provider Oracle Cloud Native Environment (OCNE)

CACPOCNE

Cluster API Control Plane Provider Oracle Cloud Native Environment (OCNE)

CAPC

Cluster API Provider CloudStack

CAPD

Cluster API Provider Docker

CAPDO

Cluster API Provider DigitalOcean

CAPG

Cluster API Google Cloud Provider

CAPH

Cluster API Provider Hetzner

CAPHV

Cluster API Provider Hivelocity

CAPIBM

Cluster API Provider IBM Cloud

CAPIO

Cluster API Operator

CAPM3

Cluster API Provider Metal3

CAPN

Cluster API Provider Nested

CAPX

Cluster API Provider Nutanix

CAPKK

Cluster API Provider KubeKey

CAPK

Cluster API Provider Kubevirt

CAPO

Cluster API Provider OpenStack

CAPOSC

Cluster API Provider Outscale

CAPOCI

Cluster API Provider Oracle Cloud Infrastructure (OCI)

CAPV

Cluster API Provider vSphere

CAPVC

Cluster API Provider vcluster

CAPVCD

Cluster API Provider VMware Cloud Director

CAPZ

Cluster API Provider Azure

CAIPAMIC

Cluster API IPAM Provider In Cluster

Cloud provider

Or Cloud service provider

Refers to an information technology (IT) company that provides computing resources (e.g. AWS, Azure, Google, etc.).

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 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 Runtime

The Cluster API execution model, a set of controllers cooperating in managing the Kubernetes cluster lifecycle.

Cluster Infrastructure

or Kubernetes Cluster Infrastructure

Defines the infrastructure that supports a Kubernetes cluster, like e.g. VPC, security groups, load balancers, etc. Please note that in the context of managed Kubernetes some of those components are going to be provided by the corresponding abstraction for a specific Cloud provider (EKS, OKE, AKS etc), and thus Cluster API should not take care of managing a subset or all those components.

Contract

Or Cluster API contract

Defines a set of rules a provider is expected to comply with in order to interact with Cluster API. Those rules can be in the form of CustomResourceDefinition (CRD) fields and/or expected behaviors to be implemented.

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. Control plane provider’s interaction with Cluster API is based on what is defined in the Cluster API contract.

See 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.

5 D

Default implementation

A feature implementation offered as part of the Cluster API project and maintained by the CAPI core team; For example KCP is a default implementation for a control plane provider.

6 E

External patch

Patch generated by an external component using Runtime SDK. Alternative to inline patch.

External patch extension

A runtime extension that implements a topology mutation hook.

7 H

Horizontal Scaling

The ability to add more machines based on policy and well-defined metrics. For example, add a machine to a cluster when CPU load average > (X) for a period of time (Y).

Host

see Server

8 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.). Infrastructure provider’s interaction with Cluster API is based on what is defined in the Cluster API contract.

Clouds infrastructure providers include AWS, Azure, or Google; while VMware, MAAS, or metal3.io can be defined as bare metal providers. When there is more than one way to obtain resources from the same infrastructure provider (e.g. EC2 vs. EKS in AWS) each way is referred to as a variant.

For a complete list of providers see Provider Implementations.

Inline patch

A patch defined inline in a ClusterClass. An alternative to an external patch.

In-place mutable fields

Fields which changes would only impact Kubernetes objects or/and controller behaviour but they won’t mutate in any way provider infrastructure nor the software running on it. In-place mutable fields are propagated in place by CAPI controllers to avoid the more elaborated mechanics of a replace rollout. They include metadata, MinReadySeconds, NodeDrainTimeout, NodeVolumeDetachTimeout and NodeDeletionTimeout but are not limited to be expanded in the future.

Instance

see Server

Immutability

A resource that does not mutate. In Kubernetes we often state the instance of a running pod is immutable or does not change once it is run. In order to make a change, a new pod is run. In the context of Cluster API we often refer to a running instance of a Machine as being immutable, from a Cluster API perspective.

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.

9 K

Kubernetes-conformant

Or Kubernetes-compliant

A cluster that passes the Kubernetes conformance tests.

k/k

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

KCP

Kubeadm Control plane Provider

10 L

Lifecycle hook

A Runtime Hook that allows external components to interact with the lifecycle of a Cluster.

See Implementing Lifecycle Hooks

11 M

Machine

Or Machine Resource

The Custom Resource for Kubernetes that represents a request to have a place to run kubelet.

See also: Server

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.

Multi-tenancy

Multi tenancy in Cluster API defines the capability of an infrastructure provider to manage different credentials, each one of them corresponding to an infrastructure tenant.

Please note that up until v1alpha3 this concept had a different meaning, referring to the capability to run multiple instances of the same provider, each one with its own credentials; starting from v1alpha4 we are disambiguating the two concepts.

See Multi-tenancy and Support multiple instances.

12 N

Node pools

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

13 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.

14 P

Patch

A set of instructions describing modifications to a Kubernetes object. Examples include JSON Patch and JSON Merge Patch.

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.

15 R

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.

See Runtime SDK

Runtime Extension provider

Refers to a provider that implements one or more runtime extensions. Runtime Extension provider’s interaction with Cluster API are based on the Open API spec for runtime hooks.

Runtime Hook

A single, well identified, extension point allowing applications built on top of Cluster API to hook into specific moments of the Cluster API Runtime, e.g. BeforeClusterUpgrade, TopologyMutationHook.

See Runtime SDK

Runtime SDK

A developer toolkit required to build Runtime Hooks and Runtime Extensions.

See Runtime SDK

16 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.

17 T

Topology

토폴로지

단일 제어 지점에서 클러스터의 컨트롤 플레인과 워커 머신의 형태를 정의하고 관리할 수 있는 클러스터 객체 사양의 필드. 클러스터의 토폴로지는 ClusterClass를 기반으로 합니다. 관리형 토폴로지라고도 합니다.

ClusterClass 참조

Topology Mutation Hook

토폴로지 변이 훅

클러스터 토폴로지의 일부인 Kubernetes 객체를 커스터마이징하기 위한 패치를 생성하기 위해 외부 컴포넌트를 허용하는 런타임 훅입니다.

토폴로지 변형 참조.

18 W

Workload Cluster

워크로드 클러스터

ClusterAPI 컨트롤러에 의해 생성된 클러스터. 이 클러스터는 부트스트랩 클러스터가 아니며 CAPI 도구가 아닌 최종 사용자가 사용하도록 되어 있다.

WorkerClass

워커 클래스

클러스터의 워커 노드 집합을 정의하는 템플릿 컬렉션. ClusterClass에는 0개 이상의 WorkerClass 정의가 포함되어 있다.

ClusterClass 참고

19 참고

• https://cluster-api.sigs.k8s.io/reference/glossary