K8S 安装 metrics-server v0.3.7

版本：
K8S：v1.16.9
metrics-server：v0.3.7

源码地址：https://github.com/kubernetes-sigs/metrics-server/

mkdir /data/metrics-server && cd /data/metrics-server

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

cp components.yaml components.yaml.ori

vi components.yaml 
# 修改3个地方：
image: juestnow/metrics-server:v0.3.7             # 改成国内源
args:
 - --kubelet-preferred-address-types=InternalIP,Hostname,InternalDNS,ExternalDNS,ExternalIP  # 默认使用node的主机名，但是coredns里面没有物理机主机名的解析，部署的时候添加一个参数
 - --cert-dir=/tmp
 - --secure-port=4443
 - --kubelet-insecure-tls                         # 直接通过InternalIP进行访问，忽略客户端证书。

docker pull juestnow/metrics-server:v0.3.7

kubectl apply -f components.yaml

kubectl get pods -n kube-system
# 检查是否正常启动
metrics-server-7d65b797b7-w8d5g        1/1     Running   0          36m

# metrics-server 需要一段时间才会收集数据。使用命令
kubectl -n kube-system top pod metrics-server-7d65b797b7-w8d5g 
NAME                              CPU(cores)   MEMORY(bytes)   
metrics-server-7d65b797b7-w8d5g   1m           13Mi 

获取 K8S pod 中的CPU,内存限制和实时资源使用率

vi k8s_pod_resource.sh

#!/bin/bash
PODFILE="/tmp/k8s-pod-tmp.txt"
LIMITSFILE="/tmp/k8s-pod-limits-tmp.txt"

NAMESPACE=$1

# 判断输入的 namespace 是否符正确
if [[ -z ${NAMESPACE} ]];then
        echo "请输入一个 K8S namespace; 可参考命令 kubectl get ns"
        exit 1
fi

K8SNS=$(kubectl get ns|awk 'NR> 1{print $1}')

result=$(echo ${K8SNS}|grep -w ${NAMESPACE})
if [[ $result = "" ]];then
        echo "你输入的 namespace 不存在; 可参考命令 kubectl get ns"
        exit 1
fi


# 获取指定 namespace 下所有的 pod 实时的指标
kubectl -n ${NAMESPACE} top pod > ${PODFILE}


get_limits()
{

        # 获取CPU限制
        CPU=$(kubectl -n ${NAMESPACE} describe pod $1 |grep -A 2 Limits|grep cpu    |awk '{print $2}')
        if [[ -z ${CPU} ]];then
                CPU=0
        fi

        # 获取内存限制
        MEM=$(kubectl -n ${NAMESPACE} describe pod $1 |grep -A 2 Limits|grep memory |awk '{print $2}')
        if [[ -z ${MEM} ]];then
                MEM=0
        fi

        printf "%7s      %10s\n" ${CPU} ${MEM}

}


podlist=$(cat ${PODFILE}|awk 'NR>1 {print $1}')

# 结果输出到 ${LIMITSFILE}
printf "%s      %s\n" CPU\(limits\)   MEMORY\(limits\) > ${LIMITSFILE}

for l in ${podlist}
do
        #kubectl -n ${NAMESPACE} describe pod ${l}
        get_limits ${l} >> ${LIMITSFILE}
done

# 合并展示结果
paste ${PODFILE} ${LIMITSFILE}


# 测试 
bash k8s_pod_resource.sh kube-system
NAME                                   CPU(cores)   MEMORY(bytes)       CPU(limits)      MEMORY(limits)
coredns-58cc8c89f4-5hvxg               4m           11Mi                      0           170Mi
coredns-58cc8c89f4-frnpq               5m           10Mi                      0           170Mi
etcd-k8s-master01                      23m          54Mi                      0               0
kube-apiserver-k8s-master01            57m          316Mi                     0               0
kube-controller-manager-k8s-master01   29m          39Mi                      0               0
kube-flannel-ds-amd64-z7ndv            2m           11Mi                   100m            50Mi
kube-proxy-nnb4v                       4m           15Mi                      0               0
kube-scheduler-k8s-master01            2m           17Mi                      0               0
metrics-server-7d65b797b7-5b82l        1m           15Mi                      0               0

若你的 K8S 集群有容器注入了 istio 之类的，一个 pod 中有几个 container 则需要使用下面的脚本

cat k8s_pod_resource.sh 

#!/bin/bash
PODFILE="/tmp/k8s-pod-tmp.txt"
LIMITSFILE="/tmp/k8s-pod-limits-tmp.txt"

NAMESPACE=$1

# 判断输入的 namespace 是否符正确
if [[ -z ${NAMESPACE} ]];then
        echo "请输入一个 K8S namespace; 可参考命令 kubectl get ns"
        exit 1
fi

K8SNS=$(kubectl get ns|awk 'NR> 1{print $1}')

result=$(echo ${K8SNS}|grep -w ${NAMESPACE})
if [[ $result = "" ]];then
        echo "你输入的 namespace 不存在; 可参考命令 kubectl get ns"
        exit 1
fi


# 获取指定 namespace 下所有的 pod 实时的指标
kubectl -n ${NAMESPACE} top pod > ${PODFILE}


get_limits()
{

        # 获取CPU限制
        CPU=$(kubectl -n ${NAMESPACE} describe pod $1 |awk '/^Containers/,/Conditions/{if(i>1)print x;x=$0;i++}'|grep -A 2 Limits|grep cpu |awk '{print $2}')

        if [[ -z ${CPU} ]];then
                CPU=0
        elif [[ $(echo ${CPU}|wc -w) != 1 ]];then
                CPU=$(echo ${CPU}|awk '{print $1}')
        fi

        # 获取内存限制
        MEM=$(kubectl -n ${NAMESPACE} describe pod $1 |awk '/^Containers/,/Conditions/{if(i>1)print x;x=$0;i++}'|grep -A 2 Limits|grep memory |awk '{print $2}')
        if [[ -z ${MEM} ]];then
                MEM=0
        elif [[ $(echo ${MEM}|wc -w) != 1 ]];then
                MEM=$(echo ${MEM}|awk '{print $1}')
        fi


        printf "%7s      %10s\n" ${CPU} ${MEM}

}


podlist=$(cat ${PODFILE}|awk 'NR>1 {print $1}')

# 结果输出到 ${LIMITSFILE}
printf "%s      %s\n" CPU\(limits\)   MEMORY\(limits\) > ${LIMITSFILE}

for l in ${podlist}
do
        #kubectl -n ${NAMESPACE} describe pod ${l}
        get_limits ${l} >> ${LIMITSFILE}
done

# 合并展示结果
paste ${PODFILE} ${LIMITSFILE}