31.kubernetes(k8s)笔记 Promethues(二) HPA 横向扩展AutoScale

前言:

prometheus：prometheus能够收集各种维度的资源指标，比如CPU利用率，网络连接的数量，网络报文的收发速率，包括进程的新建及回收速率等等，能够监控许许多多的指标，而这些指标K8S早期是不支持的，所以需要把prometheus能采集到的各种指标整合进k8s里，能让K8S根据这些指标来判断是否需要根据这些指标来进行pod的伸缩。

kube-prometheus-adapter简介

prometheus既作为监控系统来使用，也作为某些特殊的资源指标的提供者来使用。但是这些指标不是标准的K8S内建指标，称之为自定义指标，但是prometheus要想将监控采集到的数据作为指标来展示，则需要一个插件，这个插件叫kube-prometheus-adapter，这些指标判断pod是否需要伸缩的基本标准，例如根据cpu的利用率、内存使用量去进行伸缩。

HPA简介

HPA（Horizontal Pod Autoscaler）Pod自动弹性伸缩，K8S通过对Pod中运行的容器各项指标（CPU占用、内存占用、网络请求量）的检测，实现对Pod实例个数的动态新增和减少。
其中 v1版本只能基于观测核心指标进行Pod自动弹性伸缩,v2版可以实现自定义指标的自动弹性伸缩,当业务负载上升超过HPA设定值，创建新的Pod保障业务对资源的需求，当负载下载后可以通过销毁Pod是否资源来提高利用率。
HPA 依赖 metrics-server 获取的核心指标。所以我们要先安装 metrics-server 插件

metrics-server

metrics-server 通过kubelet（cAdvisor）获取监控数据，主要作用是为kube-scheduler，HPA等k8s核心组件，以及kubectl top命令和Dashboard等UI组件提供数据来源。

在新一代的K8S指标监控体系当中主要由核心指标流水线和监控指标流水线组成：

核心指标流水线：是指由kubelet、metrics-server以及由API server提供的api组成；CPU的累积使用率、内存实时使用率，Pod资源占用率以及容器磁盘占用率等等。

监控流水线：用于从系统收集各种指标数据并提供给终端用户、存储系统以及HPA，包含核心指标以及其他许多非核心指标。非核心指标本身不能被K8S所解析。所以需要kube-prometheus-adapter` 插件将prometheus采集到的数据转化为k8s能理解的格式，为k8s所使用。。

metrics-server通过 Kubernetes 聚合器 kube-aggregator注册到主 API Server 之上，而后基于 kubelet 的 Summary API 收集每个节点上的指标数据，并将它们存储于内存中然后以指标 API 格式提供，如下图：

metrics-server基于内存存储，重启后数据将全部丢失，而且它仅能留存最近收集到的指标数据，因此，如果用户期望访问历史数据，就不得不借助于第三方的监控系统（如 Prometheus 等）。

部署metrics-server
[下载官方yaml链接
](https://github.com/kubernetes...)

kubectl top命令用到的就是metrics-server核心指标因为还没有部署所以是抓取不到指标

[root@k8s-master prometheus]# kubectl top node
error: Metrics API not available
[root@k8s-master prometheus]# kubectl top pod
error: Metrics API not available
[root@k8s-master prometheus]# kubectl top pod -n kube-system
error: Metrics API not available

[root@k8s-master prometheus]# wget https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml^C
[root@k8s-master prometheus]# kubectl apply -f components.yaml
[root@k8s-master prometheus]# kubectl get pod -n kube-system
NAME                                       READY   STATUS    RESTARTS   AGE
calico-kube-controllers-5f6cfd688c-89nxp   1/1     Running   20         19d
calico-node-6qr5r                          1/1     Running   0          19d
calico-node-dgxnz                          1/1     Running   0          19d
calico-node-gdmt7                          1/1     Running   0          19d
calico-node-jdf7d                          1/1     Running   0          19d
coredns-f9fd979d6-2fn6w                    1/1     Running   0          19d
coredns-f9fd979d6-sq44h                    1/1     Running   0          19d
etcd-k8s-master                            1/1     Running   3          19d
kube-apiserver-k8s-master                  1/1     Running   0          19d
kube-controller-manager-k8s-master         1/1     Running   0          19d
kube-proxy-bh6k7                           1/1     Running   0          19d
kube-proxy-qw6lb                           1/1     Running   0          19d
kube-proxy-t2n7z                           1/1     Running   0          19d
kube-proxy-v2t9j                           1/1     Running   0          19d
kube-scheduler-k8s-master                  1/1     Running   0          8d
metrics-server-9f459d97b-f4ggw             0/1     Running   0          33m
[root@k8s-master prometheus]# kubectl describe pod  metrics-server-9f459d97b-f4ggw -n kube-system   #报错证书认证有问题
E0918 09:50:33.463133       1 scraper.go:139] "Failed to scrape node" err="Get \"https://192.168.4.170:10250/stats/summary?only_cpu_and_memory=true\": x509: cannot validate certificate for 192.168.4.170 because it doesn't contain any IP SANs" node="k8s-master"
E0918 09:50:33.543733       1 scraper.go:139] "Failed to scrape node" err="Get \"https://192.168.4.173:10250/stats/summary?only_cpu_and_memory=true\": x509: cannot validate certificate for 192.168.4.173 because it doesn't contain any IP SANs" node="k8s-node3"
E0918 09:50:33.558163       1 scraper.go:139] "Failed to scrape node" err="Get \"https://192.168.4.171:10250/stats/summary?only_cpu_and_memory=true\": x509: cannot validate certificate for 192.168.4.171 because it doesn't contain any IP SANs" node="k8s-node1"

修改yaml文件重新部署

[root@k8s-master prometheus]# vim components.yaml
apiVersion: apps/v1
kind: Deployment
......
  spec:
    containers:
    - args:
      - --cert-dir=/tmp
      - --secure-port=443
      - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
      - --kubelet-use-node-status-port
      - --metric-resolution=15s
      - --kubelet-insecure-tls  #不验证证书
      
[root@k8s-master prometheus]# kubectl delete -f components.yaml 
s
[root@k8s-master prometheus]# kubectl apply  -f components.yaml 

[root@k8s-master prometheus]# kubectl get pod -n kube-system -o wide
NAME                                       READY   STATUS    RESTARTS   AGE   IP              NODE         NOMINATED NODE   READINESS GATES
calico-kube-controllers-5f6cfd688c-89nxp   1/1     Running   20         19d   192.168.237.2   k8s-master              
calico-node-6qr5r                          1/1     Running   0          19d   192.168.4.173   k8s-node3               
calico-node-dgxnz                          1/1     Running   0          19d   192.168.4.172   k8s-node2               
calico-node-gdmt7                          1/1     Running   0          19d   192.168.4.171   k8s-node1               
calico-node-jdf7d                          1/1     Running   0          19d   192.168.4.170   k8s-master              
coredns-f9fd979d6-2fn6w                    1/1     Running   0          19d   192.168.237.1   k8s-master              
coredns-f9fd979d6-sq44h                    1/1     Running   0          19d   192.168.237.3   k8s-master              
etcd-k8s-master                            1/1     Running   3          19d   192.168.4.170   k8s-master              
kube-apiserver-k8s-master                  1/1     Running   0          19d   192.168.4.170   k8s-master              
kube-controller-manager-k8s-master         1/1     Running   0          19d   192.168.4.170   k8s-master              
kube-proxy-bh6k7                           1/1     Running   0          19d   192.168.4.173   k8s-node3               
kube-proxy-qw6lb                           1/1     Running   0          19d   192.168.4.172   k8s-node2               
kube-proxy-t2n7z                           1/1     Running   0          19d   192.168.4.170   k8s-master              
kube-proxy-v2t9j                           1/1     Running   0          19d   192.168.4.171   k8s-node1               
kube-scheduler-k8s-master                  1/1     Running   0          8d    192.168.4.170   k8s-master              
metrics-server-766c9b8df-zpt94             1/1     Running   0          61s   192.168.51.88   k8s-node3

top命令已经可以获取到指标

[root@k8s-master ~]# kubectl top node
NAME             CPU(cores)   CPU%   MEMORY(bytes)   MEMORY%   
k8s-master.org   228m         11%    2248Mi          58%       
k8s-node1.org    200m         5%     2837Mi          36%       
k8s-node2.org    218m         5%     2703Mi          34%       
k8s-node3.org    280m         7%     4184Mi          53%

[root@k8s-master ~]# kubectl top pod -n kube-system
NAME                                       CPU(cores)   MEMORY(bytes)   
calico-kube-controllers-74b8fbdb46-qhsn4   5m           69Mi            
calico-node-8bwfr                          25m          126Mi           
calico-node-cc765                          35m          151Mi           
calico-node-fwdm2                          35m          124Mi           
calico-node-gdtvh                          35m          140Mi           
calico-typha-686cfb8bb6-h9vtf              2m           27Mi            
coredns-7f6cbbb7b8-f9b8t                   2m           35Mi            
coredns-7f6cbbb7b8-vqmqj                   2m           30Mi            
etcd-k8s-master.org                        15m          141Mi           
kube-apiserver-k8s-master.org              69m          844Mi           
kube-controller-manager-k8s-master.org     11m          123Mi           
kube-proxy-9m94r                           1m           26Mi            
kube-proxy-btbxx                           5m           37Mi            
kube-proxy-d2f7r                           1m           46Mi            
kube-proxy-jrvds                           6m           27Mi            
kube-scheduler-k8s-master.org              3m           56Mi            
metrics-server-5b6dd75459-c8rmt            4m           19Mi

kube-prometheus-adapter部署

前面提到过 prometheus既作为监控系统来使用，也作为某些特殊的资源指标的提供者来使用。但是这些指标不是标准的K8S内建指标，称之为自定义指标，但是prometheus要想将监控采集到的数据作为指标来展示，则需要一个插件，这个插件叫kube-prometheus-adapter，这些指标判断pod是否需要伸缩的基本标准，例如根据cpu的利用率、内存使用量去进行伸缩。

helm 安装部署prometheus-adapter

[root@k8s-master ~]# helm search repo prometheus-adapter
NAME                                       CHART VERSION    APP VERSION    DESCRIPTION                                       
prometheus-community/prometheus-adapter    2.17.0           v0.9.0         A Helm chart for k8s prometheus adapter           
stable/prometheus-adapter                  2.5.1            v0.7.0         DEPRECATED A Helm chart for k8s prometheus adapter

[root@k8s-master prometheus-adapter]# helm pull prometheus-community/prometheus-adapter  #chart下载到本地

[root@k8s-master ~]# helm show values prometheus-community/prometheus-adapter  #检查默认配置根据实际情况修改

查看prometheus svc 确定连接地址

[root@k8s-master ~]# kubectl get svc  -n monitor 
NAME                            TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
prometheus-adapter              ClusterIP   10.96.61.209             443/TCP    27m
prometheus-alertmanager         ClusterIP   10.111.88.56             80/TCP     30h
prometheus-kube-state-metrics   ClusterIP   10.111.190.243           8080/TCP   30h
prometheus-node-exporter        ClusterIP   None                     9100/TCP   30h
prometheus-pushgateway          ClusterIP   10.103.67.173            9091/TCP   30h
prometheus-server               ClusterIP   10.111.189.44            80/TCP     30h

修改prometheus-adapter 连接的prometheus svc

[root@k8s-master prometheus-adapter]# vim values.yaml 
prometheus:
# Value is templated
url: http://prometheus-server.monitor.svc.cluster.local
port: 80
path: ""

安装prometheus-adapter

[root@k8s-master prometheus]# helm install prometheus-adapter prometheus-adapter  -n monitor
NAME: prometheus-adapter
LAST DEPLOYED: Sun Sep 19 22:23:41 2021
NAMESPACE: monitor
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
prometheus-adapter has been deployed.
In a few minutes you should be able to list metrics using the following command(s):

kubectl get --raw /apis/custom.metrics.k8s.io/v1beta1

[root@k8s-master prometheus]# kubectl get pod -n monitor -o wide
NAME                                             READY   STATUS    RESTARTS   AGE   IP               NODE        NOMINATED NODE   READINESS GATES
prometheus-adapter-5d4864b5c6-tl6wb              1/1     Running   0          41s   192.168.113.86   k8s-node1              
prometheus-alertmanager-5775f494fc-n5t9j         2/2     Running   0          15h   192.168.12.89    k8s-node2              
prometheus-kube-state-metrics-696cf79768-v2m6f   1/1     Running   0          15h   192.168.51.93    k8s-node3              
prometheus-node-exporter-489sz                   1/1     Running   2          30h   192.168.4.171    k8s-node1              
prometheus-node-exporter-6k67l                   1/1     Running   0          30h   192.168.4.173    k8s-node3              
prometheus-node-exporter-pmvdb                   1/1     Running   0          30h   192.168.4.172    k8s-node2              
prometheus-pushgateway-9fd8fbf86-p9thk           1/1     Running   0          15h   192.168.51.94    k8s-node3              
prometheus-server-7d54f5bcbc-md928               2/2     Running   0          15h   192.168.12.90    k8s-node2

抓取指标各种指标节点容器容器内部应用程序的指标等

[root@k8s-master prometheus]# kubectl get --raw /apis/custom.metrics.k8s.io/v1beta1|jq . 
{
"kind": "APIResourceList",
"apiVersion": "v1",
"groupVersion": "custom.metrics.k8s.io/v1beta1",
"resources": [
  {
    "name": "namespaces/kube_pod_container_status_restarts",
    "singularName": "",
    "namespaced": false,
    "kind": "MetricValueList",
    "verbs": [
      "get"
    ]
  },
  {
    "name": "namespaces/memory_mapped_file",
    "singularName": "",
    "namespaced": false,
    "kind": "MetricValueList",
    "verbs": [
      "get"
    ]
  },
  {
    "name": "namespaces/kube_deployment_spec_strategy_rollingupdate_max_unavailable",
    "singularName": "",
    "namespaced": false,
    "kind": "MetricValueList",
    "verbs": [
      "get"
    ]
  },
...

查看name值默认只会暴露一些常规指标

[root@k8s-master prometheus]# kubectl get --raw /apis/custom.metrics.k8s.io/v1beta1|jq '.resources[].name'
"pods/fs_reads_bytes"
"namespaces/spec_cpu_period"
"jobs.batch/kube_deployment_status_replicas_available"
"namespaces/kube_persistentvolumeclaim_resource_requests_storage_bytes"
"namespaces/kube_pod_container_status_running"
"namespaces/kube_pod_start_time"
"secrets/kube_ingress_tls"
"namespaces/kube_pod_completion_time"
"jobs.batch/kube_pod_container_status_restarts"
"namespaces/kube_deployment_spec_strategy_rollingupdate_max_unavailable"
"jobs.batch/kube_daemonset_status_updated_number_scheduled"
"jobs.batch/kube_poddisruptionbudget_status_pod_disruptions_allowed"
"pods/fs_usage_bytes"
"jobs.batch/kube_daemonset_metadata_generation"
"jobs.batch/kube_pod_owner"
"namespaces/kube_pod_container_status_restarts"
"jobs.batch/kube_deployment_metadata_generation"
"jobs.batch/kube_ingress_path"
"namespaces/kube_job_owner"

并没有自己想要的自定义指标

[root@k8s-master prometheus]# kubectl get --raw /apis/custom.metrics.k8s.io/v1beta1|grep "http_requests_per_second"  

[root@k8s-master prometheus]# kubectl get cm -n monitor
NAME                      DATA   AGE
prometheus-adapter        1      37h
prometheus-alertmanager   1      2d19h
prometheus-server         5      2d19h

暴露自定义指标需要自己定义rule

[root@k8s-master prometheus]# kubectl edit  cm prometheus-adapter  -n monitor

apiVersion: v1
data:
config.yaml: |
  rules:
  - seriesQuery: '{__name__=~"^container_.*",container!="POD",namespace!="",pod!=""}'
    seriesFilters: []
    resources:
      overrides:
        namespace:
          resource: namespace
        pod:
          resource: pod
    name:
      matches: ^container_(.*)_seconds_total$
      as: ""
    metricsQuery: sum(rate(<<.Series>>{<<.LabelMatchers>>,container!="POD"}[5m]))
      by (<<.GroupBy>>)
  - seriesQuery: '{__name__=~"^container_.*",container!="POD",namespace!="",pod!=""}'
    seriesFilters:
    - isNot: ^container_.*_seconds_total$
    resources:
      overrides:
        namespace:
          resource: namespace
        pod:
          resource: pod
    name:
      matches: ^container_(.*)_total$
      as: ""
    metricsQuery: sum(rate(<<.Series>>{<<.LabelMatchers>>,container!="POD"}[5m]))
      by (<<.GroupBy>>)

prometheus-adapter rlue规范

rules:
default: true #是否加载默认规则;
custom:
- seriesQuery: 'http_requests_total{kubernetes_namespace!="", kubernetes_pod_name!=""}'  #找出Pod资源
  resources:
    overrides :
      kubernetes_namespace: {resource: "namespace"}   #替换标签
      kubernetes_pod_name: {resource: "pod"}  #替换标签
  name:
    matches: "^(.*)_total"   #匹配时间序列指标
    as: "${1}_per_second"    #把上面http_requests_total标签前缀保持不变替换后面为_per_second
  metricsQuery: 'rate(<<.Series>>{<<.LabelMatchers>>}[2m])'  #2m钟范围向量求速率
existing:
external: []

编辑comfigmap配置添加自定义rule, 记得先备份comfigmap配置

[root@k8s-master prometheus]# kubectl get cm prometheus-adapter  -n monitor -o yaml > prometheus-adapter-secrect.yaml

[root@k8s-master prometheus]# cat  prometheus-adapter-secrect.yaml 
apiVersion: v1
data:
config.yaml: |
  rules:
  ...
  - seriesQuery: '{namespace!="",__name__!~"^container_.*"}'
    seriesFilters: []
    resources:
      template: <<.Resource>>
    name:
      matches: ^(.*)_seconds_total$
      as: ""
    metricsQuery: sum(rate(<<.Series>>{<<.LabelMatchers>>}[5m])) by (<<.GroupBy>>)
  #添加规则
  - seriesQuery: 'http_requests_total{kubernetes_namespace!="",kubernetes_pod_name!=""}'
    resources:
      overrides:
        kubernetes_namespace: {resource: "namespace"}
        kubernetes_pod_name: {resource: "pod"}
    name:
      matches: "^(.*)_total" 
      as: "${1}_per_second"
    metricsQuery: 'rate(<<.Series>>{<<.LabelMatchers>>}[2m])'
kind: ConfigMap
metadata:
annotations:
  meta.helm.sh/release-name: prometheus-adapter
  meta.helm.sh/release-namespace: monitor
creationTimestamp: "2021-09-19T14:23:47Z"  #删除原信息
labels:
  app: prometheus-adapter
  app.kubernetes.io/managed-by: Helm
  chart: prometheus-adapter-2.17.0
  heritage: Helm
  release: prometheus-adapter
managedFields:
- apiVersion: v1
  fieldsType: FieldsV1
  fieldsV1:
    f:data:
      .: {}
      f:config.yaml: {}
managedFields:   #整个字段删除
- apiVersion: v1
  fieldsType: FieldsV1
  fieldsV1:
    f:data:
      .: {}
      f:config.yaml: {}
    f:metadata:
      f:annotations:
        .: {}
        f:meta.helm.sh/release-name: {}
        f:meta.helm.sh/release-namespace: {}
      f:labels:
        .: {}
        f:app: {}
        f:app.kubernetes.io/managed-by: {}
        f:chart: {}
        f:heritage: {}
        f:release: {}
  manager: Go-http-client
  operation: Update
  time: "2021-09-19T14:23:47Z" 
name: prometheus-adapter
namespace: monitor
resourceVersion: "5118605" #删除原信息
selfLink: /api/v1/namespaces/monitor/configmaps/prometheus-adapter #删除原信息
uid: 033ad427-8f62-427e-bbe7-94a41958ee88 #删除原信息

重启Pod

[root@k8s-master prometheus]# kubectl apply -f prometheus-adapter-secrect.yaml 
Warning: kubectl apply should be used on resource created by either kubectl create --save-config or kubectl apply
configmap/prometheus-adapter configured

[root@k8s-master prometheus]# kubectl delete pod  prometheus-alertmanager-769488c787-h9s7z  -n monitor
pod "pod-21566" deleted

示例1: HPA v1 autoscale

通过核心指标Pod自动扩缩容

[root@k8s-master hpa] cat demoapp.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:
name: demoapp
spec:
replicas: 2
selector:
  matchLabels:
    app: demoapp
    controller: demoapp
template:
  metadata:
    labels :
      app: demoapp
      controller: demoapp
  spec:
    containers:
    - name: demoapp
      image: ikubernetes/demoapp:v1.0
      ports:
      - containerPort : 80
        name: http
      resources:
        requests:
          memory: "256Mi"
          cpu: "50m"
        limits:
          memory: "256Mi"
          cpu: "50m"
---
apiVersion: v1
kind: Service
metadata:
name: demoapp
spec:
selector:
  app: demoapp
  controller: demoapp
ports:
- name: http
  port: 80
  targetPort: 80


[root@k8s-master hpa] kubectl get svc -o wide
NAME         TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)   AGE     SELECTOR
demoapp      ClusterIP   10.105.4.65           80/TCP    4m57s   app=demoapp,controller=demoapp
kubernetes   ClusterIP   10.96.0.1             443/TCP   5m23s   

[root@k8s-master hpa] curl 10.105.4.65
iKubernetes demoapp v1.0 !! ClientIP: 192.168.4.170, ServerName: demoapp-557f9776fd-qmltc, ServerIP: 192.168.12.97!
[root@k8s-master hpa] curl 10.105.4.65
iKubernetes demoapp v1.0 !! ClientIP: 192.168.4.170, ServerName: demoapp-557f9776fd-wcj4n, ServerIP: 192.168.113.94!
[root@k8s-master hpa] curl 10.105.4.65
iKubernetes demoapp v1.0 !! ClientIP: 192.168.4.170, ServerName: demoapp-557f9776fd-qmltc, ServerIP: 192.168.12.97!

创建autoscale 实现自动扩缩容

[root@k8s-master hpa] kubectl  autoscale --help
Creates an autoscaler that automatically chooses and sets the number of pods
that run in a kubernetes cluster.

 Looks up a Deployment, ReplicaSet, StatefulSet, or ReplicationController by
name and creates an autoscaler that uses the given resource as a reference. An
autoscaler can automatically increase or decrease number of pods deployed within
the system as needed.

Examples:
# Auto scale a deployment "foo", with the number of pods between 2 and 10, no
target CPU utilization specified so a default autoscaling policy will be used:
kubectl autoscale deployment foo --min=2 --max=10

# Auto scale a replication controller "foo", with the number of pods between 1
and 5, target CPU utilization at 80%:
kubectl autoscale rc foo --max=5 --cpu-percent=80   #CPU使用率到80 扩容 最大数量为5

当CPU使用率为60％时Pod进行扩容最大为6个低于60％时Pod进行缩容最小为2个

[root@k8s-master hpa]# kubectl autoscale deployment/demoapp --min=2 --max=6 --cpu-percent=60    
horizontalpodautoscaler.autoscaling/demoapp autoscaled
[root@k8s-master hpa]# kubectl get hpa
NAME      REFERENCE            TARGETS         MINPODS   MAXPODS   REPLICAS   AGE
demoapp   Deployment/demoapp   /60%   2         6         0          14s
[root@k8s-master hpa]# kubectl get hpa
NAME      REFERENCE            TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
demoapp   Deployment/demoapp   2%/60%    2         6         2          21s

[root@k8s-master hpa]# kubectl get hpa demoapp  -o yaml  #详细信息
apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
......
spec:
maxReplicas: 6
minReplicas: 2
scaleTargetRef:
  apiVersion: apps/v1
  kind: Deployment
  name: demoapp
targetCPUUtilizationPercentage: 60
status:
currentCPUUtilizationPercentage: 2
currentReplicas: 2
desiredReplicas: 2

#监控autoscale状态
NAME      REFERENCE            TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
demoapp   Deployment/demoapp   2%/60%    2         6         2          19m

压测同时开两个终端或多个终端同时访问或调整访问间隔时长

#终端1
[root@k8s-master ~]# kubectl run pod-$RANDOM --image="ikubernetes/demoapp:v1.0" --rm -it --command -- /bin/sh
[root@pod-19457 /]# while true; do curl -s http://demoapp.default.svc; done
iKubernetes demoapp v1.0 !! ClientIP: 192.168.12.101, ServerName: demoapp-557f9776fd-jjq9n, ServerIP: 192.168.51.104!
iKubernetes demoapp v1.0 !! ClientIP: 192.168.12.101, ServerName: demoapp-557f9776fd-qmltc, ServerIP: 192.168.12.97!
iKubernetes demoapp v1.0 !! ClientIP: 192.168.12.101, ServerName: demoapp-557f9776fd-wcj4n, ServerIP: 192.168.113.94!
iKubernetes demoapp v1.0 !! ClientIP: 192.168.12.101, ServerName: demoapp-557f9776fd-ftr64, ServerIP: 192.168.51.105!
iKubernetes demoapp v1.0 !! ClientIP: 192.168.12.101, ServerName: demoapp-557f9776fd-bj7dj, ServerIP: 192.168.113.97!
iKubernetes demoapp v1.0 !! ClientIP: 192.168.12.101, ServerName: demoapp-557f9776fd-gkwsz, ServerIP: 192.168.12.100

#终端2
[root@k8s-master authfiles]# kubectl run pod-$RANDOM  --image="ikubernetes/demoapp:v1.0" --rm -it --command -- /bin/sh

[root@pod-25921 /]# while true; do curl -s http://demoapp.default.svc; sleep .1; done 
iKubernetes demoapp v1.0 !! ClientIP: 192.168.113.96, ServerName: demoapp-557f9776fd-jjq9n, ServerIP: 192.168.51.104!
iKubernetes demoapp v1.0 !! ClientIP: 192.168.113.96, ServerName: demoapp-557f9776fd-wcj4n, ServerIP: 192.168.113.94!
iKubernetes demoapp v1.0 !! ClientIP: 192.168.113.96, ServerName: demoapp-557f9776fd-jjq9n, ServerIP: 192.168.51.104!
iKubernetes demoapp v1.0 !! ClientIP: 192.168.113.96, ServerName: demoapp-557f9776fd-wcj4n, ServerIP: 192.168.113.94!
iKubernetes demoapp v1.0 !! ClientIP: 192.168.113.96, ServerName: demoapp-557f9776fd-jjq9n, ServerIP: 192.168.51.104!

查看监控结果

[root@k8s-master hpa]# kubectl get hpa -w
NAME      REFERENCE            TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
demoapp   Deployment/demoapp   2%/60%    2         6         2          19m
demoapp   Deployment/demoapp   8%/60%    2         6         2          21m
demoapp   Deployment/demoapp   14%/60%   2         6         2          22m
demoapp   Deployment/demoapp   17%/60%   2         6         2          22m
demoapp   Deployment/demoapp   8%/60%    2         6         2          22m
demoapp   Deployment/demoapp   68%/60%   2         6         2          23m
demoapp   Deployment/demoapp   70%/60%   2         6         3          23m  #扩缩容并不会到达阀值后立刻执行，为了防止Pod抖动 会有一定的延时 缩容的延时会更长
demoapp   Deployment/demoapp   72%/60%   2         6         3          23m
demoapp   Deployment/demoapp   51%/60%   2         6         3          23m
demoapp   Deployment/demoapp   46%/60%   2         6         3          24m
demoapp   Deployment/demoapp   32%/60%   2         6         3          24m
demoapp   Deployment/demoapp   63%/60%   2         6         3          24m
demoapp   Deployment/demoapp   83%/60%   2         6         3          25m
demoapp   Deployment/demoapp   49%/60%   2         6         5          28m
demoapp   Deployment/demoapp   53%/60%   2         6         5          28m
demoapp   Deployment/demoapp   51%/60%   2         6         5          29m
demoapp   Deployment/demoapp   52%/60%   2         6         5          29m
demoapp   Deployment/demoapp   50%/60%   2         6         5          29m
demoapp   Deployment/demoapp   44%/60%   2         6         5          29m
demoapp   Deployment/demoapp   46%/60%   2         6         5          30m
demoapp   Deployment/demoapp   50%/60%   2         6         5          30m
demoapp   Deployment/demoapp   67%/60%   2         6         5          30m
demoapp   Deployment/demoapp   86%/60%   2         6         6          31m
demoapp   Deployment/demoapp   81%/60%   2         6         6          31m
demoapp   Deployment/demoapp   78%/60%   2         6         6          31m
demoapp   Deployment/demoapp   70%/60%   2         6         6          31m
demoapp   Deployment/demoapp   74%/60%   2         6         6          32m
demoapp   Deployment/demoapp   76%/60%   2         6         6          32m
demoapp   Deployment/demoapp   53%/60%   2         6         6          32m
demoapp   Deployment/demoapp   44%/60%   2         6         6          32m
demoapp   Deployment/demoapp   40%/60%   2         6         6          33m
demoapp   Deployment/demoapp   39%/60%   2         6         6          33m
demoapp   Deployment/demoapp   38%/60%   2         6         6          34m
demoapp   Deployment/demoapp   40%/60%   2         6         6          34m  #扩缩容并不会到达阀值后立刻执行，为了防止Pod抖动 会有一定的延时 缩容的延时会更长
demoapp   Deployment/demoapp   39%/60%   2         6         6          34m
demoapp   Deployment/demoapp   40%/60%   2         6         6          35m
demoapp   Deployment/demoapp   41%/60%   2         6         6          35m
demoapp   Deployment/demoapp   40%/60%   2         6         6          35m
demoapp   Deployment/demoapp   39%/60%   2         6         6          36m
demoapp   Deployment/demoapp   42%/60%   2         6         6          36m
demoapp   Deployment/demoapp   20%/60%   2         6         6          36m
demoapp   Deployment/demoapp   7%/60%    2         6         6          36m
demoapp   Deployment/demoapp   6%/60%    2         6         6          37m
demoapp   Deployment/demoapp   6%/60%    2         6         6          37m  #压测关掉之前开始缩容
demoapp   Deployment/demoapp   6%/60%    2         6         5          37m
demoapp   Deployment/demoapp   7%/60%    2         6         5          38m
demoapp   Deployment/demoapp   8%/60%    2         6         5          38m
demoapp   Deployment/demoapp   7%/60%    2         6         5          39m
demoapp   Deployment/demoapp   8%/60%    2         6         5          40m
demoapp   Deployment/demoapp   7%/60%    2         6         5          40m
demoapp   Deployment/demoapp   8%/60%    2         6         5          40m
demoapp   Deployment/demoapp   7%/60%    2         6         5          40m
demoapp   Deployment/demoapp   8%/60%    2         6         5          41m
demoapp   Deployment/demoapp   8%/60%    2         6         5          41m
demoapp   Deployment/demoapp   8%/60%    2         6         2          41m
demoapp   Deployment/demoapp   12%/60%   2         6         2          41m
demoapp   Deployment/demoapp   17%/60%   2         6         2          42m
demoapp   Deployment/demoapp   16%/60%   2         6         2          42m
demoapp   Deployment/demoapp   17%/60%   2         6         2          42m
demoapp   Deployment/demoapp   16%/60%   2         6         2          43m
demoapp   Deployment/demoapp   17%/60%   2         6         2          43m
demoapp   Deployment/demoapp   2%/60%    2         6         2          43m

示例2: HPA v2 autoscale

通过自定义指标Pod自动扩缩容使用前面自定义指标prometheus-adapter http_requests_total

[root@k8s-master hpa]# cat metrics-app.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: metrics-app
spec:
  replicas: 2
  selector:
    matchLabels:
      app: metrics-app
      controller: metrics-app
  template:
    metadata:
      labels :
        app: metrics-app
        controller: metrics-app
      annotations:
        prometheus.io/scrape: "true"   #打开指标抓取 以下两个指标
        prometheus.io/port: "80"
        prometheus.io/path: "/metrics" 
    spec:
      containers:
      - image: ikubernetes/metrics-app
        name: metrics-app
        ports:
        - name: web
          containerPort: 80
        resources:
          requests:
            memory: "50Mi"
            cpu: "100m"
          limits:
            memory: "100Mi"
            cpu: "200m"
---
apiVersion: v1
kind: Service
metadata:
  name: metrics-app
spec :
  type: NodePort
  selector:
    app: metrics-app
    controller: metrics-app
  ports :
  - name: http
    port: 80
    targetPort: 80

[root@k8s-master hpa]# kubectl apply -f metrics-app.yaml 
deployment.apps/metrics-app created
service/metrics-app unchanged

[root@k8s-master hpa]# kubectl get svc
NAME          TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
kubernetes    ClusterIP   10.96.0.1               443/TCP        8h
metrics-app   NodePort    10.100.76.148           80:30665/TCP   33m

[root@k8s-master hpa]# curl 10.100.76.148
Hello! My name is metrics-app-6bf7d6779b-8ztnb. The last 10 seconds, the average QPS has been 0.2. Total requests served: 34
[root@k8s-master hpa]# curl 10.100.76.148
Hello! My name is metrics-app-6bf7d6779b-cb5wf. The last 10 seconds, the average QPS has been 0.1. Total requests served: 32

[root@k8s-master ~]# curl 10.100.76.148/metrics
# HELP http_requests_total The amount of requests in total
# TYPE http_requests_total counter
http_requests_total 25
# HELP http_requests_per_second The amount of requests per second the latest ten seconds
# TYPE http_requests_per_second gauge
http_requests_per_second 0.1

prometheus 已经能抓取到指标