5

Kubernetes API 资源使用

 2 years ago
source link: https://www.qikqiak.com/post/k8s-api-resources-group-and-version/
Go to the source link to view the article. You can view the picture content, updated content and better typesetting reading experience. If the link is broken, please click the button below to view the snapshot at that time.
neoserver,ios ssh client

Kubernetes API 资源使用-阳明的博客|Kubernetes|Istio|Prometheus|Python|Golang|云原生

API Resource

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：<APIGROUP>/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   <string>
     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 <object>
     Data contains the configuration data. Each key must consist of alphanumeric
     characters, '-', '_' or '.'.

   kind <string>
     Kind is a string value representing the REST resource this object
     represents. Servers may infer this from the endpoint the client submits
     requests to. Cannot be updated. In CamelCase. More info:
     https://git.k8s.io/community/contributors/devel/api-conventions.md#types-kinds

   metadata <Object>
     Standard object's metadata. More info:
     https://git.k8s.io/community/contributors/devel/api-conventions.md#metadata

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/v1

API 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 <API_RESOURCE_NAME>.<API_VERSION>.<API_GROUP>，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"

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。

Kubernetes进阶训练营

微信公众号

扫描下面的二维码关注我们的微信公众帐号，在微信公众帐号中回复◉加群◉即可加入到我们的 kubernetes 讨论群里面共同学习。

wechat-account-qrcode

「真诚赞赏，手留余香」


report

Recommend

About Joyk


Aggregate valuable and interesting links.
Joyk means Joy of geeK