容器编排系统K8s之APIService资源

  • A+
所属分类:linux技术
摘要

  前文我们聊到了k8s上crd资源的使用和相关说明,回顾请参考:https://www.cnblogs.com/qiuhom-1874/p/14267400.html;今天我们来了解下k8s的第二种扩展机制自定义apiserver,以及apiservice资源的相关话题;

  前文我们聊到了k8s上crd资源的使用和相关说明,回顾请参考:https://www.cnblogs.com/qiuhom-1874/p/14267400.html;今天我们来了解下k8s的第二种扩展机制自定义apiserver,以及apiservice资源的相关话题;

  在开始聊自定义apiserver前,我们先来了解下k8s原生的apiserver;其实apiserver就是一个https服务器,我们可以使用kubectl工具通过https协议请求apiserver创建资源,删除资源,查看资源等等操作;每个请求都对应着RESTful api中的请求方法,对应资源就是http协议中的url路径;比如我们要创建一个pod,其kubectl请求apiserver 使用post方法将资源定义提交给apiserver;pod资源就是对应群组中的某个版本下某个名称空间下的某个pod资源;

  apiserver资源组织逻辑

容器编排系统K8s之APIService资源

  提示:客户端访问apiserver,对应资源类似上图中的组织方式;比如访问default名称空间下某个pod,其路径就为/apis/core/v1/namespace/default/pod/mypod;对应resource包含名称空间以及对应资源类型;

  k8s原生apiserver组成

  k8s原生apiserver主要有两个组件组成,第一个组件aggregator,其功能类似web代理服务器,第二个组件就是真正的apiserver;其工作逻辑是,用户请求首先送达给aggregator,由aggregator根据用户请求的资源,将对应请求路由至apiserver;简单讲aggregator这个组件主要作用就是用来路由用户请求;默认情况aggregator会把所有请求都路由至原生的apiserver上进行响应;如果我们需要自定义apiserver,就需要在默认的aggregator上使用apiservice资源将自定义apiserver注册到原生的apiserver上,让其用户请求能够被路由至自定义apiserver进行响应;如下图

容器编排系统K8s之APIService资源

  提示:apiserver是k8s的唯一访问入口,默认客户端的所有操作都是发送给apiserver进行响应,我们自定义的apiserver要想能够被客户端访问,就必须通过内建apiserver中的aggregator组件中的路由信息,把对应路径的访问路由至对应apiserver进行访问;对应aggregator中的路由信息,由k8s内建apiservice资源定义;简单讲apiservice资源就是用来定义原生apiserver中aggregator组件上的路由信息;该路由就是将某某端点的访问路由至对应apiserver;

  查看原生apiserver中的群组/版本信息

[root@master01 ~]# kubectl api-versions admissionregistration.k8s.io/v1 admissionregistration.k8s.io/v1beta1 apiextensions.k8s.io/v1 apiextensions.k8s.io/v1beta1 apiregistration.k8s.io/v1 apiregistration.k8s.io/v1beta1 apps/v1 authentication.k8s.io/v1 authentication.k8s.io/v1beta1 authorization.k8s.io/v1 authorization.k8s.io/v1beta1 autoscaling/v1 autoscaling/v2beta1 autoscaling/v2beta2 batch/v1 batch/v1beta1 certificates.k8s.io/v1 certificates.k8s.io/v1beta1 coordination.k8s.io/v1 coordination.k8s.io/v1beta1 crd.projectcalico.org/v1 discovery.k8s.io/v1beta1 events.k8s.io/v1 events.k8s.io/v1beta1 extensions/v1beta1 flowcontrol.apiserver.k8s.io/v1beta1 mongodb.com/v1 networking.k8s.io/v1 networking.k8s.io/v1beta1 node.k8s.io/v1 node.k8s.io/v1beta1 policy/v1beta1 rbac.authorization.k8s.io/v1 rbac.authorization.k8s.io/v1beta1 scheduling.k8s.io/v1 scheduling.k8s.io/v1beta1 stable.example.com/v1 storage.k8s.io/v1 storage.k8s.io/v1beta1 v1 [root@master01 ~]# 

  提示:只有上面列出的群组版本才能够被客户端访问,即客户端只能访问上述列表中群组版本中的资源,没有出现群组版本是一定不会被客户端访问到;

  apiservice资源的使用

  示例:创建apiservice资源

[root@master01 ~]# cat apiservice-demo.yaml apiVersion: apiregistration.k8s.io/v1 kind: APIService metadata:   name: v2beta1.auth.ilinux.io spec:   insecureSkipTLSVerify: true   group: auth.ilinux.io   groupPriorityMinimum: 1000   versionPriority: 15   service:     name: auth-api     namespace: default   version: v2beta1 [root@master01 ~]#  

  提示:apiservice资源属于apiregistration.k8s.io/v1群组,其类型为APIService,其中spec.insecureSkipTLSVerify字段用来描述是否忽略安全验证,即不验证https证书;true表示不验证,false表示要验证;group字段用来描述对应自定义apiserver的群组;groupPriorityMinimum字段用来描述对应群组的优先级;versionPriority字段用来描述对应群组版本的优先级;service字段是用来描述把对应群组版本的请求路由至某个service;该service就是对应自定义apiserver关联的service;version字段用来描述对应apiserver属于对应群组中的某个版本;上述资源清单表示在aggregator上注册auth.ilinux.io/v2beta1这个端点,该端点对应的后端apiserver的service是default名称空间下的auth-api service;即客户端访问auth.ilinux.io/v2beta1下的资源都会被路由至default名称空间下的auth-api service进行响应;

  应用清单

[root@master01 ~]# kubectl apply -f apiservice-demo.yaml apiservice.apiregistration.k8s.io/v2beta1.auth.ilinux.io created [root@master01 ~]# kubectl get apiservice |grep auth.ilinux.io v2beta1.auth.ilinux.io                 default/auth-api   False (ServiceNotFound)   16s [root@master01 ~]# kubectl api-versions |grep auth.ilinux.io auth.ilinux.io/v2beta1 [root@master01 ~]#  

  提示:可以看到应用清单以后,对应的端点信息就出现在api-versions中;

  上述清单只是用来说明对应apiservice资源的使用;其实应用上述清单创建apiservice资源没有实质的作用,其原因是我们对应名称空间下并没有对应的服务,也没有对应自定义apiserver;所以通常自定义apiserver,我们会用到apiservice资源来把自定义apiserver整合进原生apiserver中;接下来我们部署一个真正意义上的自定义apiserver

  部署metrics-server

  metrics-server是用来扩展k8s的第三方apiserver,其主要作用是收集pod或node上的cpu,内存,磁盘等指标数据,并提供一个api接口供kubectl top命令访问;默认情况kubectl top 命令是没法正常使用,其原因是默认apiserver上没有对应的接口提供收集pod或node的cpu,内存,磁盘等核心指标数据;kubectl top命令主要用来显示pod/node资源的cpu,内存,磁盘的占用比例;该命令能够正常使用必须依赖Metrics API;

  默认没有部署metrics server使用kubectl top pod/node查看pod或节点的cpu,内存占用比例

[root@master01 ~]# kubectl top Display Resource (CPU/Memory/Storage) usage.   The top command allows you to see the resource consumption for nodes or pods.   This command requires Metrics Server to be correctly configured and working on the server.  Available Commands:   node        Display Resource (CPU/Memory/Storage) usage of nodes   pod         Display Resource (CPU/Memory/Storage) usage of pods  Usage:   kubectl top [flags] [options]  Use "kubectl <command> --help" for more information about a given command. Use "kubectl options" for a list of global command-line options (applies to all commands). [root@master01 ~]# kubectl top pod error: Metrics API not available [root@master01 ~]# kubectl top node error: Metrics API not available [root@master01 ~]#  

  提示:默认没有部署metrics server,使用kubectl top pod/node命令,它会告诉我们没有可用的metrics api;

  部署metrics server

  下载部署清单

[root@master01 ~]# mkdir metrics-server [root@master01 ~]# cd metrics-server [root@master01 metrics-server]# wget https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.4.0/components.yaml --2021-01-14 23:54:30--  https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.4.0/components.yaml Resolving github.com (github.com)... 52.74.223.119 Connecting to github.com (github.com)|52.74.223.119|:443... connected. HTTP request sent, awaiting response... 302 Found Location: https://github-production-release-asset-2e65be.s3.amazonaws.com/92132038/c700f080-1f7e-11eb-9e30-864a63f442f4?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F20210114%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20210114T155432Z&X-Amz-Expires=300&X-Amz-Signature=fc5a6f41ca50ec22e87074a778d2cb35e716ae6c3231afad17dfaf8a02203e35&X-Amz-SignedHeaders=host&actor_id=0&key_id=0&repo_id=92132038&response-content-disposition=attachment%3B%20filename%3Dcomponents.yaml&response-content-type=application%2Foctet-stream [following] --2021-01-14 23:54:32--  https://github-production-release-asset-2e65be.s3.amazonaws.com/92132038/c700f080-1f7e-11eb-9e30-864a63f442f4?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F20210114%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20210114T155432Z&X-Amz-Expires=300&X-Amz-Signature=fc5a6f41ca50ec22e87074a778d2cb35e716ae6c3231afad17dfaf8a02203e35&X-Amz-SignedHeaders=host&actor_id=0&key_id=0&repo_id=92132038&response-content-disposition=attachment%3B%20filename%3Dcomponents.yaml&response-content-type=application%2Foctet-stream Resolving github-production-release-asset-2e65be.s3.amazonaws.com (github-production-release-asset-2e65be.s3.amazonaws.com)... 52.217.39.44 Connecting to github-production-release-asset-2e65be.s3.amazonaws.com (github-production-release-asset-2e65be.s3.amazonaws.com)|52.217.39.44|:443... connected. HTTP request sent, awaiting response... 200 OK Length: 3962 (3.9K) [application/octet-stream] Saving to: ‘components.yaml’  100%[===========================================================================================>] 3,962       11.0KB/s   in 0.4s     2021-01-14 23:54:35 (11.0 KB/s) - ‘components.yaml’ saved [3962/3962]  [root@master01 metrics-server]# ls components.yaml [root@master01 metrics-server]#  

  修改部署清单内容

[root@master01 metrics-server]# cat components.yaml apiVersion: v1 kind: ServiceAccount metadata:   labels:     k8s-app: metrics-server   name: metrics-server   namespace: kube-system --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRole metadata:   labels:     k8s-app: metrics-server     rbac.authorization.k8s.io/aggregate-to-admin: "true"     rbac.authorization.k8s.io/aggregate-to-edit: "true"     rbac.authorization.k8s.io/aggregate-to-view: "true"   name: system:aggregated-metrics-reader rules: - apiGroups:   - metrics.k8s.io   resources:   - pods   - nodes   verbs:   - get   - list   - watch --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRole metadata:   labels:     k8s-app: metrics-server   name: system:metrics-server rules: - apiGroups:   - ""   resources:   - pods   - nodes   - nodes/stats   - namespaces   - configmaps   verbs:   - get   - list   - watch --- apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata:   labels:     k8s-app: metrics-server   name: metrics-server-auth-reader   namespace: kube-system roleRef:   apiGroup: rbac.authorization.k8s.io   kind: Role   name: extension-apiserver-authentication-reader subjects: - kind: ServiceAccount   name: metrics-server   namespace: kube-system --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata:   labels:     k8s-app: metrics-server   name: metrics-server:system:auth-delegator roleRef:   apiGroup: rbac.authorization.k8s.io   kind: ClusterRole   name: system:auth-delegator subjects: - kind: ServiceAccount   name: metrics-server   namespace: kube-system --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata:   labels:     k8s-app: metrics-server   name: system:metrics-server roleRef:   apiGroup: rbac.authorization.k8s.io   kind: ClusterRole   name: system:metrics-server subjects: - kind: ServiceAccount   name: metrics-server   namespace: kube-system --- apiVersion: v1 kind: Service metadata:   labels:     k8s-app: metrics-server   name: metrics-server   namespace: kube-system spec:   ports:   - name: https     port: 443     protocol: TCP     targetPort: https   selector:     k8s-app: metrics-server --- apiVersion: apps/v1 kind: Deployment metadata:   labels:     k8s-app: metrics-server   name: metrics-server   namespace: kube-system spec:   selector:     matchLabels:       k8s-app: metrics-server   strategy:     rollingUpdate:       maxUnavailable: 0   template:     metadata:       labels:         k8s-app: metrics-server     spec:       containers:       - args:         - --cert-dir=/tmp         - --secure-port=4443         - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname         - --kubelet-use-node-status-port         - --kubelet-insecure-tls         image: k8s.gcr.io/metrics-server/metrics-server:v0.4.0         imagePullPolicy: IfNotPresent         livenessProbe:           failureThreshold: 3           httpGet:             path: /livez             port: https             scheme: HTTPS           periodSeconds: 10         name: metrics-server         ports:         - containerPort: 4443           name: https           protocol: TCP         readinessProbe:           failureThreshold: 3           httpGet:             path: /readyz             port: https             scheme: HTTPS           periodSeconds: 10         securityContext:           readOnlyRootFilesystem: true           runAsNonRoot: true           runAsUser: 1000         volumeMounts:         - mountPath: /tmp           name: tmp-dir       nodeSelector:         kubernetes.io/os: linux       priorityClassName: system-cluster-critical       serviceAccountName: metrics-server       volumes:       - emptyDir: {}         name: tmp-dir --- apiVersion: apiregistration.k8s.io/v1 kind: APIService metadata:   labels:     k8s-app: metrics-server   name: v1beta1.metrics.k8s.io spec:   group: metrics.k8s.io   groupPriorityMinimum: 100   insecureSkipTLSVerify: true   service:     name: metrics-server     namespace: kube-system   version: v1beta1   versionPriority: 100 [root@master01 metrics-server]#  

  提示:在deploy中,spec.template.containers.args字段中加上--kubelet-insecure-tls选项,表示不验证客户端证书;上述清单主要用deploy控制器将metrics server运行为一个pod,然后授权metrics-server用户能够对pod/node资源进行只读权限;然后把metrics.k8s.io/v1beta1注册到原生apiserver上,让其客户端访问metrics.k8s.io下的资源能够被路由至metrics-server这个服务上进行响应;

  应用资源清单

[root@master01 metrics-server]# kubectl apply -f components.yaml serviceaccount/metrics-server created clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader created clusterrole.rbac.authorization.k8s.io/system:metrics-server created rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader created clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator created clusterrolebinding.rbac.authorization.k8s.io/system:metrics-server created service/metrics-server created deployment.apps/metrics-server created apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io created [root@master01 metrics-server]#  

  验证:查看原生apiserver是否有metrics.k8s.io/v1beta1?

[root@master01 metrics-server]# kubectl api-versions|grep metrics metrics.k8s.io/v1beta1 [root@master01 metrics-server]#  

  提示:可以看到metrics.k8s.io/v1beta1群组已经注册到原生apiserver上;

  查看metrics server pod是否运行正常?

[root@master01 metrics-server]# kubectl get pods -n kube-system NAME                                       READY   STATUS    RESTARTS   AGE calico-kube-controllers-744cfdf676-kh6rm   1/1     Running   4          5d7h canal-5bt88                                2/2     Running   20         11d canal-9ldhl                                2/2     Running   22         11d canal-fvts7                                2/2     Running   20         11d canal-mwtg4                                2/2     Running   23         11d canal-rt8nn                                2/2     Running   21         11d coredns-7f89b7bc75-k9gdt                   1/1     Running   32         37d coredns-7f89b7bc75-kp855                   1/1     Running   31         37d etcd-master01.k8s.org                      1/1     Running   36         37d kube-apiserver-master01.k8s.org            1/1     Running   14         13d kube-controller-manager-master01.k8s.org   1/1     Running   43         37d kube-flannel-ds-fnd2w                      1/1     Running   5          5d5h kube-flannel-ds-k9l4k                      1/1     Running   7          5d5h kube-flannel-ds-s7w2j                      1/1     Running   4          5d5h kube-flannel-ds-vm4mr                      1/1     Running   6          5d5h kube-flannel-ds-zgq92                      1/1     Running   37         37d kube-proxy-74fxn                           1/1     Running   10         10d kube-proxy-fbl6c                           1/1     Running   8          10d kube-proxy-n82sf                           1/1     Running   10         10d kube-proxy-ndww5                           1/1     Running   11         10d kube-proxy-v8dhk                           1/1     Running   11         10d kube-scheduler-master01.k8s.org            1/1     Running   39         37d metrics-server-58fcfcc9d-drbw2             1/1     Running   0          32s [root@master01 metrics-server]#  

  提示:可以看到对应pod已经正常运行;

  查看pod里的日志是否正常?

[root@master01 metrics-server]# kubectl logs metrics-server-58fcfcc9d-drbw2 -n kube-system I0114 17:52:03.601493       1 serving.go:325] Generated self-signed cert (/tmp/apiserver.crt, /tmp/apiserver.key) E0114 17:52:04.140587       1 pathrecorder.go:107] registered "/metrics" from goroutine 1 [running]: runtime/debug.Stack(0x1942e80, 0xc00069aed0, 0x1bb58b5)         /usr/local/go/src/runtime/debug/stack.go:24 +0x9d k8s.io/apiserver/pkg/server/mux.(*PathRecorderMux).trackCallers(0xc00028afc0, 0x1bb58b5, 0x8)         /go/pkg/mod/k8s.io/[email protected]/pkg/server/mux/pathrecorder.go:109 +0x86 k8s.io/apiserver/pkg/server/mux.(*PathRecorderMux).Handle(0xc00028afc0, 0x1bb58b5, 0x8, 0x1e96f00, 0xc0006d88d0)         /go/pkg/mod/k8s.io/[email protected]/pkg/server/mux/pathrecorder.go:173 +0x84 k8s.io/apiserver/pkg/server/routes.MetricsWithReset.Install(0xc00028afc0)         /go/pkg/mod/k8s.io/[email protected]/pkg/server/routes/metrics.go:43 +0x5d k8s.io/apiserver/pkg/server.installAPI(0xc00000a1e0, 0xc000589b00)         /go/pkg/mod/k8s.io/[email protected]/pkg/server/config.go:711 +0x6c k8s.io/apiserver/pkg/server.completedConfig.New(0xc000589b00, 0x1f099c0, 0xc0001449b0, 0x1bbdb5a, 0xe, 0x1ef29e0, 0x2cef248, 0x0, 0x0, 0x0)         /go/pkg/mod/k8s.io/[email protected]/pkg/server/config.go:657 +0xb45 sigs.k8s.io/metrics-server/pkg/server.Config.Complete(0xc000589b00, 0xc000599440, 0xc000599b00, 0xdf8475800, 0xc92a69c00, 0x0, 0x0, 0xdf8475800)         /go/src/sigs.k8s.io/metrics-server/pkg/server/config.go:52 +0x312 sigs.k8s.io/metrics-server/cmd/metrics-server/app.runCommand(0xc00001c6e0, 0xc000114600, 0x0, 0x0)         /go/src/sigs.k8s.io/metrics-server/cmd/metrics-server/app/start.go:66 +0x157 sigs.k8s.io/metrics-server/cmd/metrics-server/app.NewMetricsServerCommand.func1(0xc0000d9340, 0xc0005a4cd0, 0x0, 0x5, 0x0, 0x0)         /go/src/sigs.k8s.io/metrics-server/cmd/metrics-server/app/start.go:37 +0x33 github.com/spf13/cobra.(*Command).execute(0xc0000d9340, 0xc00013a130, 0x5, 0x5, 0xc0000d9340, 0xc00013a130)         /go/pkg/mod/github.com/spf13/[email protected]/command.go:842 +0x453 github.com/spf13/cobra.(*Command).ExecuteC(0xc0000d9340, 0xc00013a180, 0x0, 0x0)         /go/pkg/mod/github.com/spf13/[email protected]/command.go:950 +0x349 github.com/spf13/cobra.(*Command).Execute(...)         /go/pkg/mod/github.com/spf13/[email protected]/command.go:887 main.main()         /go/src/sigs.k8s.io/metrics-server/cmd/metrics-server/metrics-server.go:38 +0xae I0114 17:52:04.266492       1 requestheader_controller.go:169] Starting RequestHeaderAuthRequestController I0114 17:52:04.267021       1 shared_informer.go:240] Waiting for caches to sync for RequestHeaderAuthRequestController I0114 17:52:04.266641       1 secure_serving.go:197] Serving securely on [::]:4443 I0114 17:52:04.266670       1 tlsconfig.go:240] Starting DynamicServingCertificateController I0114 17:52:04.266682       1 dynamic_serving_content.go:130] Starting serving-cert::/tmp/apiserver.crt::/tmp/apiserver.key I0114 17:52:04.266688       1 configmap_cafile_content.go:202] Starting client-ca::kube-system::extension-apiserver-authentication::client-ca-file I0114 17:52:04.267120       1 shared_informer.go:240] Waiting for caches to sync for client-ca::kube-system::extension-apiserver-authentication::client-ca-file I0114 17:52:04.266692       1 configmap_cafile_content.go:202] Starting client-ca::kube-system::extension-apiserver-authentication::requestheader-client-ca-file I0114 17:52:04.267301       1 shared_informer.go:240] Waiting for caches to sync for client-ca::kube-system::extension-apiserver-authentication::requestheader-client-ca-file I0114 17:52:04.367448       1 shared_informer.go:247] Caches are synced for client-ca::kube-system::extension-apiserver-authentication::requestheader-client-ca-file  I0114 17:52:04.367472       1 shared_informer.go:247] Caches are synced for client-ca::kube-system::extension-apiserver-authentication::client-ca-file  I0114 17:52:04.367462       1 shared_informer.go:247] Caches are synced for RequestHeaderAuthRequestController  [root@master01 metrics-server]#  

  提示:只要metrics server pod没有出现错误日志,或者无法注册等信息,就表示pod里的容器运行正常;

  验证:使用kubectl top 命令查看pod的cpu ,内存占比,看看对应命令是否可以正常执行?

[root@master01 metrics-server]# kubectl top node NAME               CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%    master01.k8s.org   235m         11%    1216Mi          70%        node01.k8s.org     140m         3%     747Mi           20%        node02.k8s.org     120m         3%     625Mi           17%        node03.k8s.org     133m         3%     594Mi           16%        node04.k8s.org     125m         3%     700Mi           19%        [root@master01 metrics-server]# kubectl top pods -n kube-system NAME                                       CPU(cores)   MEMORY(bytes)    calico-kube-controllers-744cfdf676-kh6rm   2m           23Mi             canal-5bt88                                50m          118Mi            canal-9ldhl                                22m          86Mi             canal-fvts7                                49m          106Mi            canal-mwtg4                                57m          113Mi            canal-rt8nn                                56m          113Mi            coredns-7f89b7bc75-k9gdt                   3m           12Mi             coredns-7f89b7bc75-kp855                   3m           15Mi             etcd-master01.k8s.org                      25m          72Mi             kube-apiserver-master01.k8s.org            99m          410Mi            kube-controller-manager-master01.k8s.org   14m          88Mi             kube-flannel-ds-fnd2w                      3m           45Mi             kube-flannel-ds-k9l4k                      3m           27Mi             kube-flannel-ds-s7w2j                      4m           46Mi             kube-flannel-ds-vm4mr                      3m           45Mi             kube-flannel-ds-zgq92                      2m           19Mi             kube-proxy-74fxn                           1m           27Mi             kube-proxy-fbl6c                           1m           23Mi             kube-proxy-n82sf                           1m           25Mi             kube-proxy-ndww5                           1m           25Mi             kube-proxy-v8dhk                           2m           23Mi             kube-scheduler-master01.k8s.org            3m           33Mi             metrics-server-58fcfcc9d-drbw2             6m           23Mi             [root@master01 metrics-server]#  

  提示:可以看到kubectl top命令可以正常执行,说明metrics server 部署成功没有问题;

  以上就是使用apiservice资源结合自定义apiserver扩展k8s功能的示例,简单总结apiservice资源的主要作用就是在aggregator上创建对应的路由信息,该路由信息的主要作用是将对应端点访问路由至自定义apiserver所对应的service进行响应;