Kubernetes Pod垂直自動伸縮（VPA）

時間 2020-10-02

標籤 kubernetes pod 垂直自動伸縮 vpa 简体版

原文原文鏈接

VPA 簡介

VPA 全稱 Vertical Pod Autoscaler，即垂直 Pod 自動擴縮容，它根據容器資源使用率自動設置 CPU 和內存的requests，從而容許在節點上進行適當的調度，以便爲每一個 Pod 提供適當的資源。
它既能夠縮小過分請求資源的容器，也能夠根據其使用狀況隨時提高資源不足的容量。
PS: VPA不會改變Pod的資源limits值。node

廢話很少說，直接上圖，看VPA工做流程

接下來開始實戰nginx

部署metrics-server

一、下載部署清單文件git

wget  https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.3.7/components.yaml

二、修改components.yaml文件github

修改了鏡像地址，gcr.io爲我本身的倉庫
修改了metrics-server啓動參數args，要否則會報錯unable to fully scrape metrics from source kubelet_summary...

- name: metrics-server
        image: scofield/metrics-server:v0.3.7
        imagePullPolicy: IfNotPresent
        args:
          - --cert-dir=/tmp
          - --secure-port=4443
          - /metrics-server
          - --kubelet-insecure-tls
          - --kubelet-preferred-address-types=InternalIP

三、執行部署web

kubectl  apply -f components.yaml

四、驗證docker

[root@k8s-node001 metrics-server]# kubectl  get po -n kube-system
NAME                                       READY   STATUS    RESTARTS   AGE
metrics-server-7947cb98b6-xw6b8            1/1     Running   0          10m

能獲取要top信息視爲成功
[root@k8s-node001 metrics-server]# kubectl  top nodes
NAME          CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%
k8s-node001   618m         7%       4796Mi           15%
k8s-node003   551m         6%       5522Mi           17%
k8s-node004   308m         3%       5830Mi           18%
k8s-node005   526m         6%       5997Mi           38%
k8s-node002   591m         7%       5306Mi           33%

部署vertical-pod-autoscaler

一、克隆autoscaler項目apache

git clone https://github.com/kubernetes/autoscaler.git

二、修改部署文件，將gcr倉庫該爲我本身的倉庫api

admission-controller-deployment.yaml
us.gcr.io/k8s-artifacts-prod/autoscaling/vpa-admission-controller:0.8.0
改成
scofield/vpa-admission-controller:0.8.0

recommender-deployment.yaml
us.gcr.io/k8s-artifacts-prod/autoscaling/vpa-recommender:0.8.0
改成
image: scofield/vpa-recommender:0.8.0

updater-deployment.yaml
us.gcr.io/k8s-artifacts-prod/autoscaling/vpa-updater:0.8.0
改成
scofield/vpa-updater:0.8.0

三、部署bash

[root@k8s-node001 vertical-pod-autoscaler]#  cd autoscaler/vertical-pod-autoscaler
[root@k8s-node001 vertical-pod-autoscaler]#  ./hack/vpa-up.sh
Warning: apiextensions.k8s.io/v1beta1 CustomResourceDefinition is deprecated in v1.16+, unavailable in v1.22+; use apiextensions.k8s.io/v1 CustomResourceDefinition
customresourcedefinition.apiextensions.k8s.io/verticalpodautoscalers.autoscaling.k8s.io created
customresourcedefinition.apiextensions.k8s.io/verticalpodautoscalercheckpoints.autoscaling.k8s.io created
clusterrole.rbac.authorization.k8s.io/system:metrics-reader created
clusterrole.rbac.authorization.k8s.io/system:vpa-actor created
clusterrole.rbac.authorization.k8s.io/system:vpa-checkpoint-actor created
clusterrole.rbac.authorization.k8s.io/system:evictioner created
clusterrolebinding.rbac.authorization.k8s.io/system:metrics-reader created
clusterrolebinding.rbac.authorization.k8s.io/system:vpa-actor created
clusterrolebinding.rbac.authorization.k8s.io/system:vpa-checkpoint-actor created
clusterrole.rbac.authorization.k8s.io/system:vpa-target-reader created
clusterrolebinding.rbac.authorization.k8s.io/system:vpa-target-reader-binding created
clusterrolebinding.rbac.authorization.k8s.io/system:vpa-evictionter-binding created
serviceaccount/vpa-admission-controller created
clusterrole.rbac.authorization.k8s.io/system:vpa-admission-controller created
clusterrolebinding.rbac.authorization.k8s.io/system:vpa-admission-controller created
clusterrole.rbac.authorization.k8s.io/system:vpa-status-reader created
clusterrolebinding.rbac.authorization.k8s.io/system:vpa-status-reader-binding created
serviceaccount/vpa-updater created
deployment.apps/vpa-updater created
serviceaccount/vpa-recommender created
deployment.apps/vpa-recommender created
Generating certs for the VPA Admission Controller in /tmp/vpa-certs.
Generating RSA private key, 2048 bit long modulus (2 primes)
............................................................................+++++
.+++++
e is 65537 (0x010001)
Generating RSA private key, 2048 bit long modulus (2 primes)
............+++++
...........................................................................+++++
e is 65537 (0x010001)
Signature ok
subject=CN = vpa-webhook.kube-system.svc
Getting CA Private Key
Uploading certs to the cluster.
secret/vpa-tls-certs created
Deleting /tmp/vpa-certs.
deployment.apps/vpa-admission-controller created
service/vpa-webhook created

四、查看結果，能夠看到metrics-server和vpa都已經正常運行了app

[root@k8s-node001 autoscaler-master]# kubectl  get po -n kube-system
NAME                                        READY   STATUS    RESTARTS   AGE
metrics-server-7947cb98b6-xw6b8             1/1     Running   0          46m
vpa-admission-controller-7d87559549-g77h9   1/1     Running   0          10m
vpa-recommender-84bf7fb9db-65669            1/1     Running   0          10m
vpa-updater-79cc46c7bb-5p889                1/1     Running   0          10m

示例1 updateMode: "Off"

一、首先咱們部署一個nginx服務,部署到namespace: vpa中

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx
  name: nginx
  namespace: vpa
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx
        name: nginx
        resources:
          requests:
            cpu: 100m
            memory: 250Mi

看下結果，正常運行了2個pod

[root@k8s-node001 examples]# kubectl  get po -n vpa
NAME                         READY   STATUS    RESTARTS   AGE
pod/nginx-6884b849f7-fswx5   1/1     Running   0          5m54s
pod/nginx-6884b849f7-wz6b8   1/1     Running   0          5m54s

二、爲了便宜壓測，咱們建立一個NodePort類型的service

[root@k8s-node001 examples]# cat  nginx-vpa-ingress.yaml
apiVersion: v1
kind: Service
metadata:
  name: nginx
  namespace: vpa
spec:
  type: NodePort
  ports:
  - port: 80
    targetPort: 80
  selector:
    app: nginx

[root@k8s-node001 examples]# kubectl  get svc -n vpa
NAME    TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
nginx   NodePort   10.97.250.131   <none>        80:32621/TCP   55s

[root@k8s-node001 examples]# curl -I   192.168.100.185:32621
HTTP/1.1 200 OK

三、建立VPA
這裏先使用updateMode: "Off"模式，這種模式僅獲取資源推薦不更新Pod

[root@k8s-node001 examples]# cat   nginx-vpa-demo.yaml
apiVersion: autoscaling.k8s.io/v1beta2
kind: VerticalPodAutoscaler
metadata:
  name: nginx-vpa
  namespace: vpa
spec:
  targetRef:
    apiVersion: "apps/v1"
    kind: Deployment
    name: nginx
  updatePolicy:
    updateMode: "Off"
  resourcePolicy:
    containerPolicies:
    - containerName: "nginx"
      minAllowed:
        cpu: "250m"
        memory: "100Mi"
      maxAllowed:
        cpu: "2000m"
        memory: "2048Mi"

四、查看部署結果

[root@k8s-node001 examples]# kubectl  get vpa -n vpa
NAME        AGE
nginx-vpa   2m34s

五、使用describe查看vpa詳情，主要關注Container Recommendations

[root@k8s-node001 examples]# kubectl  describe  vpa nginx-vpa   -n vpa
Name:         nginx-vpa
Namespace:    vpa
....略去10000字 哈哈......
  Update Policy:
    Update Mode:  Off
Status:
  Conditions:
    Last Transition Time:  2020-09-28T04:04:25Z
    Status:                True
    Type:                  RecommendationProvided
  Recommendation:
    Container Recommendations:
      Container Name:  nginx
      Lower Bound:
        Cpu:     250m
        Memory:  262144k
      Target:
        Cpu:     250m
        Memory:  262144k
      Uncapped Target:
        Cpu:     25m
        Memory:  262144k
      Upper Bound:
        Cpu:     803m
        Memory:  840190575
Events:          <none>

其中

Lower Bound:                 下限值
Target:                           推薦值
Upper Bound:                 上限值
Uncapped Target:           若是沒有爲VPA提供最小或最大邊界，則表示目標利用率
上述結果代表，推薦的 Pod 的 CPU 請求爲 25m，推薦的內存請求爲 262144k 字節。

六、如今咱們對nginx進行壓測
執行壓測命令

[root@k8s-node001 examples]# ab -c 100 -n 10000000 http://192.168.100.185:32621/
This is ApacheBench, Version 2.3 <$Revision: 1843412 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking 192.168.100.185 (be patient)
Completed 1000000 requests
Completed 2000000 requests
Completed 3000000 requests

七、幾分鐘後再觀察VPA Recommendation變化

[root@k8s-node001 ~]# kubectl  describe  vpa nginx-vpa   -n vpa |tail -n 20 
  Conditions:
    Last Transition Time:  2020-09-28T04:04:25Z
    Status:                True
    Type:                  RecommendationProvided
  Recommendation:
    Container Recommendations:
      Container Name:  nginx
      Lower Bound:
        Cpu:     250m
        Memory:  262144k
      Target:
        Cpu:     476m
        Memory:  262144k
      Uncapped Target:
        Cpu:     476m
        Memory:  262144k
      Upper Bound:
        Cpu:     2
        Memory:  387578728
Events:          <none>

從輸出信息能夠看出，VPA對Pod給出了推薦值：Cpu: 476m，由於咱們這裏設置了updateMode: "Off"，因此不會更新Pod

示例2 updateMode: "Auto"

一、如今我把updateMode: "Auto"，看看VPA會有什麼動做
這裏我把resources改成：memory: 50Mi，cpu: 100m

[root@k8s-node001 examples]# kubectl  apply -f nginx-vpa.yaml
deployment.apps/nginx created
[root@k8s-node001 examples]# cat nginx-vpa.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx
  name: nginx
  namespace: vpa
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx
        name: nginx
        resources:
          requests:
            cpu: 100m
            memory: 50Mi

[root@k8s-node001 examples]# kubectl  get po  -n vpa
NAME                     READY   STATUS    RESTARTS   AGE
nginx-7ff65f974c-f4vgl   1/1     Running   0          114s
nginx-7ff65f974c-v9ccx   1/1     Running   0          114s

二、再次部署vpa,這裏VPA部署文件nginx-vpa-demo.yaml只改了updateMode: "Auto"和name: nginx-vpa-2

[root@k8s-node001 examples]# cat  nginx-vpa-demo.yaml
apiVersion: autoscaling.k8s.io/v1beta2
kind: VerticalPodAutoscaler
metadata:
  name: nginx-vpa-2
  namespace: vpa
spec:
  targetRef:
    apiVersion: "apps/v1"
    kind: Deployment
    name: nginx
  updatePolicy:
    updateMode: "Auto"
  resourcePolicy:
    containerPolicies:
    - containerName: "nginx"
      minAllowed:
        cpu: "250m"
        memory: "100Mi"
      maxAllowed:
        cpu: "2000m"
        memory: "2048Mi"

[root@k8s-node001 examples]# kubectl apply -f nginx-vpa-demo.yaml
verticalpodautoscaler.autoscaling.k8s.io/nginx-vpa created

[root@k8s-node001 examples]# kubectl  get vpa -n vpa
NAME        AGE
nginx-vpa-2   9s

三、再次壓測

ab -c 1000 -n 100000000 http://192.168.100.185:32621/

四、幾分鐘後，使用describe查看vpa詳情，一樣只關注Container Recommendations

[root@k8s-node001 ~]# kubectl  describe  vpa nginx-vpa-2    -n vpa |tail -n 30
      Min Allowed:
        Cpu:     250m
        Memory:  100Mi
  Target Ref:
    API Version:  apps/v1
    Kind:         Deployment
    Name:         nginx
  Update Policy:
    Update Mode:  Auto
Status:
  Conditions:
    Last Transition Time:  2020-09-28T04:48:25Z
    Status:                True
    Type:                  RecommendationProvided
  Recommendation:
    Container Recommendations:
      Container Name:  nginx
      Lower Bound:
        Cpu:     250m
        Memory:  262144k
      Target:
        Cpu:     476m
        Memory:  262144k
      Uncapped Target:
        Cpu:     476m
        Memory:  262144k
      Upper Bound:
        Cpu:     2
        Memory:  262144k
Events:          <none>

Target變成了Cpu: 587m ，Memory: 262144k

五、來看下event事件

[root@k8s-node001 ~]# kubectl  get event -n vpa
LAST SEEN   TYPE      REASON              OBJECT                        MESSAGE
33m         Normal    Pulling             pod/nginx-7ff65f974c-f4vgl    Pulling image "nginx"
33m         Normal    Pulled              pod/nginx-7ff65f974c-f4vgl    Successfully pulled image "nginx" in 15.880996269s
33m         Normal    Created             pod/nginx-7ff65f974c-f4vgl    Created container nginx
33m         Normal    Started             pod/nginx-7ff65f974c-f4vgl    Started container nginx
26m         Normal    EvictedByVPA        pod/nginx-7ff65f974c-f4vgl    Pod was evicted by VPA Updater to apply resource recommendation.
26m         Normal    Killing             pod/nginx-7ff65f974c-f4vgl    Stopping container nginx
35m         Normal    Scheduled           pod/nginx-7ff65f974c-hnzr5    Successfully assigned vpa/nginx-7ff65f974c-hnzr5 to k8s-node005
35m         Normal    Pulling             pod/nginx-7ff65f974c-hnzr5    Pulling image "nginx"
34m         Normal    Pulled              pod/nginx-7ff65f974c-hnzr5    Successfully pulled image "nginx" in 40.750855715s
34m         Normal    Scheduled           pod/nginx-7ff65f974c-v9ccx    Successfully assigned vpa/nginx-7ff65f974c-v9ccx to k8s-node004
33m         Normal    Pulling             pod/nginx-7ff65f974c-v9ccx    Pulling image "nginx"
33m         Normal    Pulled              pod/nginx-7ff65f974c-v9ccx    Successfully pulled image "nginx" in 15.495315629s
33m         Normal    Created             pod/nginx-7ff65f974c-v9ccx    Created container nginx
33m         Normal    Started             pod/nginx-7ff65f974c-v9ccx    Started container nginx

從輸出信息能夠了解到，vpa執行了EvictedByVPA，自動停掉了nginx，而後使用 VPA推薦的資源啓動了新的nginx
，咱們查看下nginx的pod能夠獲得確認

[root@k8s-node001 ~]# kubectl  describe po nginx-7ff65f974c-2m9zl -n vpa
Name:         nginx-7ff65f974c-2m9zl
Namespace:    vpa
Priority:     0
Node:         k8s-node004/192.168.100.184
Start Time:   Mon, 28 Sep 2020 00:46:19 -0400
Labels:       app=nginx
              pod-template-hash=7ff65f974c
Annotations:  cni.projectcalico.org/podIP: 100.67.191.53/32
              vpaObservedContainers: nginx
              vpaUpdates: Pod resources updated by nginx-vpa: container 0: cpu request, memory request
Status:       Running
IP:           100.67.191.53
IPs:
  IP:           100.67.191.53
Controlled By:  ReplicaSet/nginx-7ff65f974c
Containers:
  nginx:
    Container ID:   docker://c96bcd07f35409d47232a0bf862a76a56352bd84ef10a95de8b2e3f6681df43d
    Image:          nginx
    Image ID:       docker-pullable://nginx@sha256:c628b67d21744fce822d22fdcc0389f6bd763daac23a6b77147d0712ea7102d0
    Port:           <none>
    Host Port:      <none>
    State:          Running
      Started:      Mon, 28 Sep 2020 00:46:38 -0400
    Ready:          True
    Restart Count:  0
    Requests:
      cpu:        476m
      memory:     262144k

看重點Requests：cpu: 476m，memory: 262144k
再回頭看看部署文件

requests:
            cpu: 100m
            memory: 50Mi

如今能夠知道VPA作了哪些事了吧。固然，隨着服務的負載的變化，VPA的推薦之也會不斷變化。當目前運行的pod的資源達不到VPA的推薦值，就會執行pod驅逐，從新部署新的足夠資源的服務。

VPA使用限制

不能與HPA（Horizontal Pod Autoscaler ）一塊兒使用
Pod好比使用副本控制器，例如屬於Deployment或者StatefulSet

VPA有啥好處

Pod 資源用其所需，因此集羣節點使用效率高。
Pod 會被安排到具備適當可用資源的節點上。
沒必要運行基準測試任務來肯定 CPU 和內存請求的合適值。
VPA 能夠隨時調整 CPU 和內存請求，無需人爲操做，所以能夠減小維護時間。

最後滴最後，VPA是Kubernetes比較新的功能，尚未在生產環境大規模實踐過，不建議在線上環境使用自動更新模式，可是使用推薦模式你能夠更好了解服務的資源使用狀況。
更多信息請前往官網查看

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