prometheus是一套监控工具
    exporter是像服务发送监控数据的客户端服务，node-exporter是对主机的常规监控
    可以编译启动或docker启动node-exporter
    https://github.com/prometheus/node_exporter
    但是怎么把这个node-exporter做到系统服务里？

    1）编写一个启动脚本：

    1. [root@xxx ~]# cat /usr/local/node_exporter/node-exporter.sh 
    2. #!/bin/sh
    3. [ "$1" == "start" ] || [ "$1" == "stop" ] || ( echo "$0 need parameter:[start] or [stop]?"  && exit -1 ) 
    5. pidfile=/var/run/docker/node-exporter.pid
    7. cid=`docker ps |grep node-exporter |awk '{print $1}'`
    8. cida=`docker ps -a|grep node-exporter|awk '{print $1}'`
    10. if [ "$1" == "start" ];then
    11.   if [ "$cid" != "" ];then
    12.     echo node-exporter is running.Need not start.
    13.   elif [ "$cida" != "" ];then
    14.     docker start $cida
    15.     pid=`pgrep node-exporter`
    16.     echo pid=$pid
    17.     echo $pid > $pidfile
    18.   else
    19.     docker run -d --net="host" --pid="host" --name=node-exporter -v "/:/host:ro,rslave" quay.io/prometheus/node-exporter --path.rootfs=/host
    20.     pid=`pgrep node_exporter`
    21.     echo pid=$pid
    22.     echo $pid > $pidfile
    23.   fi
    24. elif [ "$1" == "stop" ];then
    25.   if [ "$cid" != "" ];then
    26.     docker stop $cid
    27.     docker rm $cid
    28.   elif [ "$cida" != "" ];then
    29.     docker rm $cida
    30.   else
    31.     echo node-exporter is not running.Need not stop.
    32.   fi
    33. fi

    2）编写系统服务配置文件：

    1. [root@xxx ~]# cat /etc/systemd/system/multi-user.target.wants/node-exporter.service 
    2. [Unit]
    3. Description=prometheus/node-exporter
    4. After=docker.service 
    6. [Service]
    7. Type=forking
    8. PIDFile=/var/run/docker/node-exporter.pid
    9. ExecStart=/usr/bin/sh /usr/local/node_exporter/node-exporter.sh start
    10. ExecStop=/usr/bin/sh /usr/local/node_exporter/node-exporter.sh stop
    12. [Install]
    13. WantedBy=multi-user.target

    3）systemctl daemon-reload后可以使用systemctl start/stop 服务