Kubernetes使用声明式的 API 让系统更加健壮。但是这样也就意味着我们想要系统执行某些操作就需要通过使用CLI或者REST API来创建一个资源对象，为此，我们需要定义 API 资源的名称、组和版本等信息。但是很多用户就会为此感到困惑了，因为有太多的资源、太多的版本、太多的组了，这些都非常容易产生混淆。如果我们通过 YAML 文件定义过 Deployment 这样的资源清单文件的话，那么你应该会看到apiVersion: apps/v1beta2、apiVersion: apps/v1等等这样的信息，那么我们到底应该使用哪一个呢？哪一个才是正确的呢？如何检查Kubernetes集群支持哪些？其实我们使用kubectl工具就可以来解决我们的这些疑惑。
原文链接：https://akomljen.com/kubernetes-api-resources-which-group-and-version-to-use/
API Resources
我们可以通过下面的命令来获取Kubernetes集群支持的所有 API 资源：
$ kubectl api-resources -o wide
NAME SHORTNAMES APIGROUP NAMESPACED KIND VERBS
bindings true Binding [create]
componentstatuses cs false ComponentStatus [get list]
configmaps cm true ConfigMap [create delete deletecollection get list patch update watch]
endpoints ep true Endpoints [create delete deletecollection get list patch update watch]
events ev true Event [create delete deletecollection get list patch update watch]
limitranges limits true LimitRange [create delete deletecollection get list patch update watch]
namespaces ns false Namespace [create delete get list patch update watch]
nodes no false Node [create delete deletecollection get list patch proxy update watch]
persistentvolumeclaims pvc true PersistentVolumeClaim [create delete deletecollection get list patch update watch]
persistentvolumes pv false PersistentVolume [create delete deletecollection get list patch update watch]
pods po true Pod [create delete deletecollection get list patch proxy update watch]
podtemplates true PodTemplate [create delete deletecollection get list patch update watch]
replicationcontrollers rc true ReplicationController [create delete deletecollection get list patch update watch]
resourcequotas quota true ResourceQuota [create delete deletecollection get list patch update watch]
secrets true Secret [create delete deletecollection get list patch update watch]
serviceaccounts sa true ServiceAccount [create delete deletecollection get list patch update watch]
services svc true Service [create delete get list patch proxy update watch]
mutatingwebhookconfigurations admissionregistration.k8s.io false MutatingWebhookConfiguration [create delete deletecollection get list patch update watch]
validatingwebhookconfigurations admissionregistration.k8s.io false ValidatingWebhookConfiguration [create delete deletecollection get list patch update watch]
customresourcedefinitions crd apiextensions.k8s.io false CustomResourceDefinition [create delete deletecollection get list patch update watch]
apiservices apiregistration.k8s.io false APIService [create delete deletecollection get list patch update watch]
controllerrevisions apps true ControllerRevision [create delete deletecollection get list patch update watch]
daemonsets ds apps true DaemonSet [create delete deletecollection get list patch update watch]
deployments deploy apps true Deployment [create delete deletecollection get list patch update watch]
replicasets rs apps true ReplicaSet [create delete deletecollection get list patch update watch]
statefulsets sts apps true StatefulSet [create delete deletecollection get list patch update watch]
...需要注意的是在
1.11.0以上版本的集群中kubectl才支持上面的api-resources命令。
上面的命令输出了很多有用的信息：
-
SHORTNAMES– 资源名称的简写，比如 deployments 简写就是 deploy，我们可以将这些快捷方式与kubectl一起使用 -
APIGROUP– 我们可以查看官方文档以了解更多信息，但简而言之，您将在yaml文件中使用它像apiVersion：/v1 -
KIND– 资源名称 -
VERBS– 可用的方法，在您想要定义ClusterRole RBAC规则时也很有用，您还可以选择获取特定 API 组的 API 资源，例如：
$ kubectl api-resources --api-group apps -o wide
NAME SHORTNAMES APIGROUP NAMESPACED KIND VERBS
controllerrevisions apps true ControllerRevision [create delete deletecollection get list patch update watch]
daemonsets ds apps true DaemonSet [create delete deletecollection get list patch update watch]
deployments deploy apps true Deployment [create delete deletecollection get list patch update watch]
replicasets rs apps true ReplicaSet [create delete deletecollection get list patch update watch]
statefulsets sts apps true StatefulSet对于上面的每种资源类型，我们都可以使用kubectl explain命令来获取有关的资源详细信息：
$ kubectl explain configmap
DESCRIPTION:
ConfigMap holds configuration data for pods to consume.
FIELDS:
apiVersion
APIVersion defines the versioned schema of this representation of an
object. Servers should convert recognized schemas to the latest internal
value, and may reject unrecognized values. More info:
https://git.k8s.io/community/contributors/devel/api-conventions.md#resources
data
kubectl explain命令非常有用，特别是在我们不知道该如何编写YAML文件的时候，就可以使用改命令来帮助我们获得更多提示信息。
需要注意的是explain命令可能会显示旧的group/version，我们可以通过--api-version参数显示设置它，比如：
请注意，explain可能会显示旧组/版本，但您可以使用–api-version显式设置它，例如：
kubectl explain replicaset --api-version apps/v1API Versions
我们也可以使用下面的命令来获取集群支持的所有 API 版本：
$ kubectl api-versions
admissionregistration.k8s.io/v1beta1
apiextensions.k8s.io/v1beta1
apiregistration.k8s.io/v1beta1
apps/v1
apps/v1beta1
apps/v1beta2
authentication.k8s.io/v1
authentication.k8s.io/v1beta1
authorization.k8s.io/v1
authorization.k8s.io/v1beta1
autoscaling/v1
autoscaling/v2beta1
batch/v1
batch/v1beta1
certificates.k8s.io/v1beta1
certmanager.k8s.io/v1alpha1
enterprises.upmc.com/v1
events.k8s.io/v1beta1
extensions/v1beta1
metrics.k8s.io/v1beta1
monitoring.coreos.com/v1
networking.k8s.io/v1
policy/v1beta1
rbac.authorization.k8s.io/v1
rbac.authorization.k8s.io/v1beta1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1输出结果是以group/version的方式呈现的，可以通过查看此页面了解更多有关Kubernetes中 API 版本控制的信息。
有的时候，我们只想检查特定的group/version是否可以用于某些资源即可，大多数的资源都有可用的GET方法，所以我们只需要尝试获取下资源，同时提供 API 的 version 和 group 即可验证，kubectl get ，例如：
$ kubectl get deployments.v1.apps -n kube-system
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
cert-manager 1 1 1 1 1d
heapster 1 1 1 1 183d
infra-wayne 1 1 1 1 17d
kube-dns 1 1 1 1 183d
kubernetes-dashboard 1 1 1 1 202d
monitoring-grafana 1 1 1 1 183d
monitoring-influxdb 1 1 1 1 183d
tiller-deploy 1 1 1 1 98d
traefik-ingress-controller 1 1 1 1 102d如果资源不存在指定的group/version组合或者资源根本不存在，我们将会收到错误信息：
$ kubectl get deployments.v1beta.apps -n kube-system
error: the server doesn't have a resource type "deployments"总结
本文将帮助您了解YAML文件中的kind和apiVersion这两个内容，如果你想了解更多关于Kubernetes设计的信息，我建议你查看下这篇文章，谢谢。
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