kind

Documentation

Overview

Package kind provide utilities for CAPD interoperability with kindest/node images.

CAPD doesn't have direct dependencies from Kind, however, it is using kindest/node images.

As a consequence CAPD must stay in sync with Kind with regards to how kindest/node images are run when creating a new DockerMachine.

kindest/node images are created using a specific Kind version, and thus it is required to keep into account the mapping between the Kubernetes version for a kindest/node and the Kind version that created that image, so we can run it properly.

NOTE: This is the same reason why in the Kind release documentation there is a specific list of kindest/node images - uniquely identified by a sha - to be used with a Kind release.

For sake of simplification, we are grouping a set of Kind versions that runs kindest/node images in the same way into Kind mode.

Index

• type Mapping
  • func GetMapping(k8sVersion semver.Version, customImage string) Mapping
• type Mode

Types

type Mapping

type Mapping struct {
	KubernetesVersion semver.Version
	Mode              Mode
	Image             string
}

Mapping defines a mapping between a Kubernetes version, a Mode, and a pre-built Image sha.

func GetMapping

func GetMapping(k8sVersion semver.Version, customImage string) Mapping

GetMapping return the Mapping for a given Kubernetes version/custom image. If a custom image is provided, return the corresponding Mapping if defined, otherwise return the mapping for target K8sVersion if defined; if there is no exact match for a given Kubernetes version/custom image, a best effort mapping is returned. NOTE: returning a best guess mapping is a way to try to make things to work when new images are published and either CAPD code in this file is not yet updated or users/CI are using older versions of CAPD. Even if this can lead to CAPD failing in not obvious ways, we consider this an acceptable trade off given that this is a provider to be used for development only and this approach allow us bit more of flexibility in using Kindest/node images published after CAPD version is cut (without doing code changes in the list above and/or cherry-picks).

type Mode

type Mode string

Mode defines a set of Kind versions that are running images in a consistent way.

const (
	// ModeNone defined a Mode to be used when creating the CAPD load balancer, which doesn't
	// use a kindest/node image.
	ModeNone Mode = "None"

	// Mode0_19 is a Mode that identifies kind v0.19 and older; all those versions
	// are running images in a consistent way (or are too old at the time of this implementation).
	Mode0_19 Mode = "kind 0.19"

	// Mode0_20 is a Mode that identifies kind v0.20 and newer; all those versions
	// are running images in a consistent way, that differs from Mode0_19 because
	// of the adoption of CgroupnsMode = "private" when running images.
	Mode0_20 Mode = "kind 0.20"
)