Kubernetes Pod垂直自动伸缩


VPA 简介

VPA全称Vertical Pod Autoscaler,即垂直Pod自动扩缩容,它根据容器资源使用率自动设置CPU和内存的requests,从而允许在节点上进行适当的调度,以便为每个Pod提供适当的资源。

它既可以缩小过度请求资源的容器,也可以根据其使用情况随时提升资源不足的容量。

PS:VPA不会改变Pod的资源limits值。

废话不多说,直接上图,看VPA工作流程:
1.png

部署metrics-server

下载部署清单文件

[root@VM-10-48-centos ~]#  wget https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.3.7/components.yaml

修改components.yaml文件

  • 修改了镜像地址为:scofield/metrics-server:v0.3.7
  • 修改了metrics-server启动参数args


- 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

执行部署

[root@VM-10-48-centos ~]# kubectl  apply -f components.yaml

验证

[root@VM-10-48-centos ~]# kubectl get po -n kube-system | grep metrics-server
metrics-server-5b58f4df77-f7nks                          1/1     Running   0          35d

# 能获取要top信息视为成功
[root@VM-10-48-centos ~]# kubectl top nodes
NAME        CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%   
10.1.2.15   138m         3%     4207Mi          29%       
10.1.2.16   159m         4%     3138Mi          45%       
10.1.2.17   147m         3%     4118Mi          59%       
10.1.50.2   82m          4%     1839Mi          55% 

部署vertical-pod-autoscaler

克隆autoscaler项目

[root@VM-10-48-centos ~]# git clone https://github.com/kubernetes/autoscaler.git

修改部署文件

[root@VM-10-48-centos ~]# cd autoscaler/vertical-pod-autoscaler/deploy
admission-controller-deployment.yaml
us.gcr.io/k8s-artifacts-prod/autoscaling/vpa-admission-controller:0.8.0
改为
scofield/vpa-admission-controller:0.8.0

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

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

部署

[root@VM-10-48-centos ~]# cd autoscaler/vertical-pod-autoscaler
[root@VM-10-48-centos ~]# ./hack/vpa-up.sh
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



这里如果出现错误:ERROR: Failed to create CA certificate for self-signing. If the error is “unknown option -addext”, update your openssl version or deploy VPA from the vpa-release-0.8 branch
需要升级openssl的版本解决:
[root@VM-10-48-centos ~]# yum install gcc gcc-c++ -y
[root@VM-10-48-centos ~]# openssl version -a
[root@VM-10-48-centos ~]# wget https://www.openssl.org/source/openssl-1.1.1k.tar.gz && tar zxf openssl-1.1.1k.tar.gz && cd openssl-1.1.1k
[root@VM-10-48-centos ~]# ./config
[root@VM-10-48-centos ~]# make && make install
[root@VM-10-48-centos ~]# mv /usr/local/bin/openssl /usr/local/bin/openssl.bak
[root@VM-10-48-centos ~]# mv apps/openssl /usr/local/bin
[root@VM-10-48-centos ~]# openssl version -a
OpenSSL 1.1.1k  25 Mar 2021 (Library: OpenSSL 1.1.1g FIPS  21 Apr 2020)
built on: Mon Mar 29 23:48:12 2021 UTC
platform: linux-x86_64
options:  bn(64,64) rc4(16x,int) des(int) idea(int) blowfish(ptr) 
compiler: gcc -fPIC -pthread -m64 -Wa,--noexecstack -Wall -O3 -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -Wa,--noexecstack -Wa,--generate-missing-build-notes=yes -DOPENSSL_USE_NODELETE -DL_ENDIAN -DOPENSSL_PIC -DOPENSSL_CPUID_OBJ -DOPENSSL_IA32_SSE2 -DOPENSSL_BN_ASM_MONT -DOPENSSL_BN_ASM_MONT5 -DOPENSSL_BN_ASM_GF2m -DSHA1_ASM -DSHA256_ASM -DSHA512_ASM -DKECCAK1600_ASM -DRC4_ASM -DMD5_ASM -DAESNI_ASM -DVPAES_ASM -DGHASH_ASM -DECP_NISTZ256_ASM -DX25519_ASM -DPOLY1305_ASM -DZLIB -DNDEBUG -DPURIFY -DDEVRANDOM="\"/dev/urandom\""
OPENSSLDIR: "/etc/pki/tls"
ENGINESDIR: "/usr/lib64/engines-1.1"
Seeding source: os-specific

再次执行vertical-pod-autoscaler/pkg/admission-controller/gencerts.sh
2.png

查看结果

可以看到metrics-server和vpa都已经正常运行了。
[root@VM-10-48-centos ~]# kubectl get po -n kube-system | grep -E "metrics-server|vpa"
metrics-server-5b58f4df77-f7nks                          1/1     Running   0          35d
vpa-admission-controller-7ff888c959-tvtmk                1/1     Running   0          104m
vpa-recommender-74f69c56cb-zmzwg                         1/1     Running   0          104m
vpa-updater-79b88f9c55-m4xx5                             1/1     Running   0          103m

示例

updateMode: Off

1、首先我们部署一个Nginx服务,部署到namespace: vpa
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

看下结果,正常运行了2个Pod:
[root@VM-10-48-centos ~]# kubectl get po -n vpa
NAME                     READY   STATUS    RESTARTS   AGE
nginx-59fdffd754-cb5dn   1/1     Running   0          8s
nginx-59fdffd754-cw8d7   1/1     Running   0          9s

2、创建一个NodePort类型的Service
[root@VM-10-48-centos ~]# cat svc.yaml 
apiVersion: v1
kind: Service
metadata:
name: nginx
namespace: vpa
spec:
type: NodePort
ports:
- port: 80
targetPort: 80
selector:
app: nginx

[root@VM-10-48-centos ~]# kubectl get svc -n vpa | grep nginx
nginx   NodePort   10.255.253.166   <none>        80:30895/TCP   54s

[root@VM-2-16-centos ~]# curl -I 10.1.2.16:30895
HTTP/1.1 200 OK
Server: nginx/1.21.1
Date: Fri, 09 Jul 2021 09:54:58 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 06 Jul 2021 14:59:17 GMT
Connection: keep-alive
ETag: "60e46fc5-264"
Accept-Ranges: bytes

3、创建VPA

这里先使用updateMode: &quot;Off&quot;模式,这种模式仅获取资源推荐但不更新Pod
[root@VM-10-48-centos ~]# 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"

4、查看部署结果
[root@VM-10-48-centos ~]# kubectl get vpa -n vpa
NAME        MODE   CPU   MEM   PROVIDED   AGE
nginx-vpa   Off                           7s

5、使用describe查看vpa详情,主要关注Container Recommendations
[root@VM-10-48-centos ~]# kubectl describe vpa nginx-vpa -n vpa
Name:         nginx-vpa
Namespace:    vpa
Spec:
Resource Policy:
Container Policies:
  Container Name:  nginx
  Max Allowed:
    Cpu:     2000m
    Memory:  2048Mi
  Min Allowed:
    Cpu:     250m
    Memory:  100Mi
Target Ref:
API Version:  apps/v1
Kind:         Deployment
Name:         nginx
Update Policy:
Update Mode:  Off
Status:
Conditions:
Last Transition Time:  2021-07-09T09:59:50Z
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:     670m
    Memory:  700542995

其中:
Lower Bound:                 下限值
Target:                      推荐值
Upper Bound:                 上限值
Uncapped Target:             如果没有为VPA提供最小或最大边界,则表示目标利用率
上述结果表明,推荐的Pod的CPU请求为25m,推荐的内存请求为262144k字节。

6、现在对Nginx进行压测

执行压测命令:
[root@VM-10-48-centos ~]# ab -c 100 -n 10000000 http://10.1.2.16:30895/
This is ApacheBench, Version 2.3 <$Revision: 1430300 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking 10.1.2.16 (be patient)

Completed 1000000 requests
Completed 2000000 requests
Completed 3000000 requests

7、几分钟后再观察VPA Recommendation变化
[root@VM-10-48-centos ~]# kubectl describe vpa -n vpa nginx-vpa | tail -n 20
Conditions:
Last Transition Time:  2021-07-09T09:59:50Z
Status:                True
Type:                  RecommendationProvided
Recommendation:
Container Recommendations:
  Container Name:  nginx
  Lower Bound:
    Cpu:     250m
    Memory:  262144k
  Target:
    Cpu:     1643m
    Memory:  262144k
  Uncapped Target:
    Cpu:     1643m
    Memory:  262144k
  Upper Bound:
    Cpu:     2
    Memory:  562581530
Events:          <none>

从输出信息可以看出,VPA对Pod给出了推荐值:Cpu: 1643m,因为我们这里设置了updateMode: &quot;Off&quot;,所以不会更新Pod。

updateMode: Auto

1、把updateMode: “Auto”,看看VPA会有什么动作

这里把resources改为:memory: 50Mi,cpu: 100m
[root@VM-10-48-centos ~]# kubectl get po -n vpa
NAME                     READY   STATUS    RESTARTS   AGE
nginx-5594c66dc6-lzs67   1/1     Running   0          26s
nginx-5594c66dc6-zk6h9   1/1     Running   0          21s

2、再次部署VPA,这里VPA部署文件nginx-vpa-demo.yaml只改了updateMode: &quot;Auto&quot;
[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"

3、再次压测
[root@VM-10-48-centos ~]# ab -c 100 -n 10000000 http://10.1.2.16:30895/

4、几分钟后,使用describe查看vpa详情,同样只关注Container Recommendations
[root@VM-10-48-centos ~]# kubectl describe vpa nginx-vpa  -n vpa | tail -n 20
Conditions:
Last Transition Time:  2021-07-09T09:59:50Z
Status:                True
Type:                  RecommendationProvided
Recommendation:
Container Recommendations:
  Container Name:  nginx
  Lower Bound:
    Cpu:     250m
    Memory:  262144k
  Target:
    Cpu:     1643m
    Memory:  262144k
  Uncapped Target:
    Cpu:     1643m
    Memory:  262144k
  Upper Bound:
    Cpu:     2
    Memory:  511550327
Events:          <none>

Target变成了Cpu:1643m ,Memory:262144k

5、来看下event事件
[root@VM-10-48-centos ~]# kubectl get event -n vpa
LAST SEEN   TYPE     REASON                 OBJECT                        MESSAGE
38s         Normal   Scheduled              pod/nginx-5594c66dc6-d8d6h    Successfully assigned vpa/nginx-5594c66dc6-d8d6h to 10.1.2.16
38s         Normal   Pulling                pod/nginx-5594c66dc6-d8d6h    Pulling image "nginx"
37s         Normal   Pulled                 pod/nginx-5594c66dc6-d8d6h    Successfully pulled image "nginx"
37s         Normal   Created                pod/nginx-5594c66dc6-d8d6h    Created container nginx
37s         Normal   Started                pod/nginx-5594c66dc6-d8d6h    Started container nginx
3m10s       Normal   Scheduled              pod/nginx-5594c66dc6-lzs67    Successfully assigned vpa/nginx-5594c66dc6-lzs67 to 10.1.2.15
3m9s        Normal   Pulling                pod/nginx-5594c66dc6-lzs67    Pulling image "nginx"
3m5s        Normal   Pulled                 pod/nginx-5594c66dc6-lzs67    Successfully pulled image "nginx"
3m5s        Normal   Created                pod/nginx-5594c66dc6-lzs67    Created container nginx
3m5s        Normal   Started                pod/nginx-5594c66dc6-lzs67    Started container nginx
99s         Normal   EvictedByVPA           pod/nginx-5594c66dc6-lzs67    Pod was evicted by VPA Updater to apply resource recommendation.
99s         Normal   Killing                pod/nginx-5594c66dc6-lzs67    Stopping container nginx
98s         Normal   Scheduled              pod/nginx-5594c66dc6-tdmnh    Successfully assigned vpa/nginx-5594c66dc6-tdmnh to 10.1.2.15
98s         Normal   Pulling                pod/nginx-5594c66dc6-tdmnh    Pulling image "nginx"
97s         Normal   Pulled                 pod/nginx-5594c66dc6-tdmnh    Successfully pulled image "nginx"
97s         Normal   Created                pod/nginx-5594c66dc6-tdmnh    Created container nginx
97s         Normal   Started                pod/nginx-5594c66dc6-tdmnh    Started container nginx
3m5s        Normal   Scheduled              pod/nginx-5594c66dc6-zk6h9    Successfully assigned vpa/nginx-5594c66dc6-zk6h9 to 10.1.2.17
3m4s        Normal   Pulling                pod/nginx-5594c66dc6-zk6h9    Pulling image "nginx"
3m          Normal   Pulled                 pod/nginx-5594c66dc6-zk6h9    Successfully pulled image "nginx"
2m59s       Normal   Created                pod/nginx-5594c66dc6-zk6h9    Created container nginx
2m59s       Normal   Started                pod/nginx-5594c66dc6-zk6h9    Started container nginx
39s         Normal   EvictedByVPA           pod/nginx-5594c66dc6-zk6h9    Pod was evicted by VPA Updater to apply resource recommendation.
39s         Normal   Killing                pod/nginx-5594c66dc6-zk6h9    Stopping container nginx
3m10s       Normal   SuccessfulCreate       replicaset/nginx-5594c66dc6   Created pod: nginx-5594c66dc6-lzs67
3m5s        Normal   SuccessfulCreate       replicaset/nginx-5594c66dc6   Created pod: nginx-5594c66dc6-zk6h9
99s         Normal   SuccessfulCreate       replicaset/nginx-5594c66dc6   Created pod: nginx-5594c66dc6-tdmnh
38s         Normal   SuccessfulCreate       replicaset/nginx-5594c66dc6   Created pod: nginx-5594c66dc6-d8d6h
35m         Normal   Scheduled              pod/nginx-59fdffd754-cb5dn    Successfully assigned vpa/nginx-59fdffd754-cb5dn to 10.1.2.16
35m         Normal   Pulling                pod/nginx-59fdffd754-cb5dn    Pulling image "nginx"
35m         Normal   Pulled                 pod/nginx-59fdffd754-cb5dn    Successfully pulled image "nginx"
35m         Normal   Created                pod/nginx-59fdffd754-cb5dn    Created container nginx
35m         Normal   Started                pod/nginx-59fdffd754-cb5dn    Started container nginx
3m5s        Normal   Killing                pod/nginx-59fdffd754-cb5dn    Stopping container nginx
35m         Normal   Scheduled              pod/nginx-59fdffd754-cw8d7    Successfully assigned vpa/nginx-59fdffd754-cw8d7 to 10.1.2.16
35m         Normal   Pulling                pod/nginx-59fdffd754-cw8d7    Pulling image "nginx"
35m         Normal   Pulled                 pod/nginx-59fdffd754-cw8d7    Successfully pulled image "nginx"
35m         Normal   Created                pod/nginx-59fdffd754-cw8d7    Created container nginx
35m         Normal   Started                pod/nginx-59fdffd754-cw8d7    Started container nginx
2m58s       Normal   Killing                pod/nginx-59fdffd754-cw8d7    Stopping container nginx
35m         Normal   SuccessfulCreate       replicaset/nginx-59fdffd754   Created pod: nginx-59fdffd754-cw8d7
35m         Normal   SuccessfulCreate       replicaset/nginx-59fdffd754   Created pod: nginx-59fdffd754-cb5dn
3m5s        Normal   SuccessfulDelete       replicaset/nginx-59fdffd754   Deleted pod: nginx-59fdffd754-cb5dn
2m58s       Normal   SuccessfulDelete       replicaset/nginx-59fdffd754   Deleted pod: nginx-59fdffd754-cw8d7
35m         Normal   ScalingReplicaSet      deployment/nginx              Scaled up replica set nginx-59fdffd754 to 2
34m         Normal   EnsuringService        service/nginx                 Deleted Loadbalancer
34m         Normal   EnsureServiceSuccess   service/nginx                 Service Sync Success. RetrunCode: S2000
3m10s       Normal   ScalingReplicaSet      deployment/nginx              Scaled up replica set nginx-5594c66dc6 to 1
3m5s        Normal   ScalingReplicaSet      deployment/nginx              Scaled down replica set nginx-59fdffd754 to 1
3m5s        Normal   ScalingReplicaSet      deployment/nginx              Scaled up replica set nginx-5594c66dc6 to 2
2m58s       Normal   ScalingReplicaSet      deployment/nginx              Scaled down replica set nginx-59fdffd754 to 0

从输出信息可以了解到,VPA执行了EvictedByVPA,自动停掉了Nginx,然后使用 VPA推荐的资源启动了新的Nginx,我们查看下Nginx的Pod可以得到确认。
[root@VM-10-48-centos ~]# kubectl describe po -n vpa nginx-5594c66dc6-d8d6h
Name:         nginx-5594c66dc6-d8d6h
Namespace:    vpa
Priority:     0
Node:         10.1.2.16/10.1.2.16
Start Time:   Fri, 09 Jul 2021 18:09:26 +0800
Labels:       app=nginx
          pod-template-hash=5594c66dc6
Annotations:  tke.cloud.tencent.com/networks-status:
            [{
                "name": "tke-bridge",
                "interface": "eth0",
                "ips": [
                    "10.252.1.50"
                ],
                "mac": "e6:38:26:0b:c5:97",
                "default": true,
                "dns": {}
            }]
          vpaObservedContainers: nginx
          vpaUpdates: Pod resources updated by nginx-vpa: container 0: cpu request, memory request
Status:       Running
IP:           10.252.1.50
IPs:
IP:           10.252.1.50
Controlled By:  ReplicaSet/nginx-5594c66dc6
Containers:
nginx:
Container ID:   docker://42e45f5f122ba658e293395d78a073cfe51534c773f9419a179830fd6d1698ea
Image:          nginx
Image ID:       docker-pullable://nginx@sha256:8df46d7414eda82c2a8c9c50926545293811ae59f977825845dda7d558b4125b
Port:           <none>
Host Port:      <none>
State:          Running
  Started:      Fri, 09 Jul 2021 18:09:27 +0800
Ready:          True
Restart Count:  0
Requests:
  cpu:        1643m
  memory:     262144k
Environment:  <none>
Mounts:
  /var/run/secrets/kubernetes.io/serviceaccount from default-token-m2j2z (ro)

看重点Requests:cpu: 1643m,memory: 262144k

再回头看看部署文件:
requests:
cpu: 100m
memory: 50Mi


现在可以知道VPA做了哪些事了吧。当然,随着服务的负载的变化,VPA的推荐之也会不断变化。当目前运行的pod的资源达不到VPA的推荐值,就会执行pod驱逐,重新部署新的足够资源的服务。

VPA使用限制

  • 不能与HPA(Horizontal Pod Autoscaler )一起使用
  • Pod比如使用副本控制器,例如属于Deployment或者StatefulSet


VPA有啥好处

  • Pod资源用其所需,所以集群节点使用效率高。
  • Pod会被安排到具有适当可用资源的节点上。
  • 不必运行基准测试任务来确定CPU和内存请求的合适值。
  • VPA可以随时调整CPU和内存请求,无需人为操作,因此可以减少维护时间。


原文链接:https://devops.cloudcared.cn/2 ... a901/,作者:王骁

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