Kubernetes - APIs

The /api endpoint is already legacy and used only for core resources (pods, secrets, configmaps, etc.). A more modern and generic /apis/<group-name> endpoint is used for the rest of resources, including user-defined custom resources.

k8s.io (in-tree): Core

code path k8s.io/api
REST Path: /api/v1
apiVersion: "core" is skipped, i.e. apiVersion: v1.
Source code: https://github.com/kubernetes/kubernetes/tree/master/pkg/api

e.g.

apiVersion: v1
kind: Pod

k8s.io (in-tree): Non-core

REST Path: /apis/$GROUP_NAME/$VERSION
apiVersion: $GROUP_NAME/$VERSION, e.g. apiVersion: batch/v1
Groups without k8s.io: apps/v1, batch/v1, policy/v1, autoscaling/v2
Groups with k8s.io: metrics.k8s.io, networking.k8s.io, node.k8s.io, storage.k8s.io, rbac.authorization.k8s.io
Source code: https://github.com/kubernetes/kubernetes/tree/master/pkg/apis

E.g.

apiVersion: apps/v1
kind: Deployment

k8s.io: sigs / extensions

Separate repos under https://github.com/kubernetes-sigs

kind.x-k8s.io: kind, import path sigs.k8s.io/kind.
- https://github.com/kubernetes-sigs/kind
cluster.x-k8s.io: Cluster api, import path sigs.k8s.io/cluster-api.
- https://github.com/kubernetes-sigs/cluster-api

E.g.

apiVersion: cluster.x-k8s.io/v1alpha3
kind: Cluster

Addons

other projects, e.g.

knative.dev
kubevirt.io
istio.io

Custom Resources

Add your own APIs.