容器编排系统K8s之APIService资源

　　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

　　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

　　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/apiserver@v0.19.2/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/apiserver@v0.19.2/pkg/server/mux/pathrecorder.go:173 +0x84

k8s.io/apiserver/pkg/server/routes.MetricsWithReset.Install(0xc00028afc0)

        /go/pkg/mod/k8s.io/apiserver@v0.19.2/pkg/server/routes/metrics.go:43 +0x5d

k8s.io/apiserver/pkg/server.installAPI(0xc00000a1e0, 0xc000589b00)

        /go/pkg/mod/k8s.io/apiserver@v0.19.2/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/apiserver@v0.19.2/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/cobra@v1.0.0/command.go:842 +0x453

github.com/spf13/cobra.(*Command).ExecuteC(0xc0000d9340, 0xc00013a180, 0x0, 0x0)

        /go/pkg/mod/github.com/spf13/cobra@v1.0.0/command.go:950 +0x349

github.com/spf13/cobra.(*Command).Execute(...)

        /go/pkg/mod/github.com/spf13/cobra@v1.0.0/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；

巴特西

容器编排系统K8s之APIService资源

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