前文我們聊到了k8s上crd資源的使用和相關說明，回顧請參考：https://www.cnblogs.com/qiuhom-1874/p/14267400.html；今天我們來了解下k8s的第二種擴充套件機制自定義apiserver，以及apiservice資源的相關話題；
在開始聊自定義apiserver前，我們先來了解下k8s原生的apiserver；其實apiserver就是一個https伺服器，我們可以使用kubectl工具通過https協議請求apiserver建立資源，刪除資源，檢視資源等等操作；每個請求都對應著RESTful api中的請求方法，對應資源就是http協議中的url路徑；比如我們要建立一個pod，其kubectl請求apiserver 使用post方法將資源定義提交給apiserver；pod資源就是對應群組中的某個版本下某個名稱空間下的某個pod資源；
apiserver資源組織邏輯
提示：客戶端訪問apiserver，對應資源類似上圖中的組織方式；比如訪問default名稱空間下某個pod，其路徑就為/apis/core/v1/namespace/default/pod/mypod；對應resource包含名稱空間以及對應資源型別；
k8s原生apiserver組成
k8s原生apiserver主要有兩個元件組成，第一個元件aggregator，其功能類似web代理伺服器，第二個元件就是真正的apiserver；其工作邏輯是，使用者請求首先送達給aggregator，由aggregator根據使用者請求的資源，將對應請求路由至apiserver；簡單講aggregator這個元件主要作用就是用來路由使用者請求；預設情況aggregator會把所有請求都路由至原生的apiserver上進行響應；如果我們需要自定義apiserver，就需要在預設的aggregator上使用apiservice資源將自定義apiserver註冊到原生的apiserver上，讓其使用者請求能夠被路由至自定義apiserver進行響應；如下圖
提示：apiserver是k8s的唯一訪問入口，預設客戶端的所有操作都是傳送給apiserver進行響應，我們自定義的apiserver要想能夠被客戶端訪問，就必須通過內建apiserver中的aggregator元件中的路由資訊，把對應路徑的訪問路由至對應apiserver進行訪問；對應aggregator中的路由資訊，由k8s內建apiservice資源定義；簡單講apiservice資源就是用來定義原生apiserver中aggregator元件上的路由資訊；該路由就是將某某端點的訪問路由至對應apiserver；
檢視原生apiserver中的群組/版本資訊
[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：只有上面列出的群組版本才能夠被客戶端訪問，即客戶端只能訪問上述列表中群組版本中的資源，沒有出現群組版本是一定不會被客戶端訪問到；
apiservice資源的使用
示例：建立apiservice資源
[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資源屬於apiregistration.k8s.io/v1群組，其型別為APIService，其中spec.insecureSkipTLSVerify欄位用來描述是否忽略安全驗證，即不驗證https證書；true表示不驗證，false表示要驗證；group欄位用來描述對應自定義apiserver的群組；groupPriorityMinimum欄位用來描述對應群組的優先順序；versionPriority欄位用來描述對應群組版本的優先順序；service欄位是用來描述把對應群組版本的請求路由至某個service；該service就是對應自定義apiserver關聯的service；version欄位用來描述對應apiserver屬於對應群組中的某個版本；上述資源清單表示在aggregator上註冊auth.ilinux.io/v2beta1這個端點，該端點對應的後端apiserver的service是default名稱空間下的auth-api service；即客戶端訪問auth.ilinux.io/v2beta1下的資源都會被路由至default名稱空間下的auth-api service進行響應；
應用清單
[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：可以看到應用清單以後，對應的端點資訊就出現在api-versions中；
上述清單只是用來說明對應apiservice資源的使用；其實應用上述清單建立apiservice資源沒有實質的作用，其原因是我們對應名稱空間下並沒有對應的服務，也沒有對應自定義apiserver；所以通常自定義apiserver，我們會用到apiservice資源來把自定義apiserver整合進原生apiserver中；接下來我們部署一個真正意義上的自定義apiserver
部署metrics-server
metrics-server是用來擴充套件k8s的第三方apiserver，其主要作用是收集pod或node上的cpu，記憶體，磁碟等指標資料，並提供一個api介面供kubectl top命令訪問；預設情況kubectl top 命令是沒法正常使用，其原因是預設apiserver上沒有對應的介面提供收集pod或node的cpu，記憶體，磁碟等核心指標資料；kubectl top命令主要用來顯示pod/node資源的cpu，記憶體，磁碟的佔用比例；該命令能夠正常使用必須依賴Metrics API；
預設沒有部署metrics server使用kubectl top pod/node檢視pod或節點的cpu，記憶體佔用比例
[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：預設沒有部署metrics server，使用kubectl top pod/node命令，它會告訴我們沒有可用的metrics api；
部署metrics server
下載部署清單
[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]#
修改部署清單內容
[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欄位中加上--kubelet-insecure-tls選項，表示不驗證客戶端證書；上述清單主要用deploy控制器將metrics server執行為一個pod，然後授權metrics-server使用者能夠對pod/node資源進行只讀許可權；然後把metrics.k8s.io/v1beta1註冊到原生apiserver上，讓其客戶端訪問metrics.k8s.io下的資源能夠被路由至metrics-server這個服務上進行響應；
應用資源清單
[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]#
驗證：檢視原生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群組已經註冊到原生apiserver上；
檢視metrics server pod是否執行正常？
[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：可以看到對應pod已經正常執行；
檢視pod裡的日誌是否正常？
[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沒有出現錯誤日誌，或者無法註冊等資訊，就表示pod裡的容器執行正常；
驗證：使用kubectl top 命令檢視pod的cpu ，記憶體佔比，看看對應命令是否可以正常執行？
[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命令可以正常執行，說明metrics server 部署成功沒有問題；
以上就是使用apiservice資源結合自定義apiserver擴充套件k8s功能的示例，簡單總結apiservice資源的主要作用就是在aggregator上建立對應的路由資訊，該路由資訊的主要作用是將對應端點訪問路由至自定義apiserver所對應的service進行響應；