Client守护进程Supervisor总结

Supervisor是一款Linux下的进程管理软件。最主要的两个功能是:

• 将非daemon程序变成deamon方式运行
• 对程序进行监控，当程序退出时，可以自动拉起程序

PS：好好研究一下supervisor的实现原理。监听一个sock文件然后可以管理子进程里面的启动，状态，关掉。这种机制非常类似于watchdog的机制。

安装

Supervisor是基于python开发的。安装Supervisor前，需要先安装python。Supervisor可以通过pip或者easy_install安装。

• 通过pip安装

  pip install supervisor

• 通过easy_install安装

  easy_install supervisor

基本使用

• 生成配置文件

Supervisor没有默认配置文件，需要手工执行命令生成配置文件：

启动Supervisor:

supervisord -c /etc/supervisord.conf

停止Supervisor(子进程也会被停止)

supervisorctl shutdown

查看Supervisor是否已经启动：

[root@aaa blog.cheyo.net]# ps -ef | grep supervisor | grep -v grep
root      1170     1  0 18:57 ?        00:00:00 /usr/bin/python /usr/bin/supervisord
[root@aaa blog.cheyo.net]#

查看业务进程是否已经被拉起：

[root@aaa blog.cheyo.net]# supervisorctl status
check12306                       RUNNING   pid 1230, uptime 0:04:39
[root@aaa blog.cheyo.net]#

维护命令

Supervisor可通过维护命令supervisorctl管理或通过web管理界面管理。维护命令supervisorctl有两种用法。一种是命令式，一种是交互式。

• 命令式

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# 查询各进程运行状态 supervisorctl status # 启、停、重启业务进程,check12306为进程名,即[program:check12306]里配置的值  supervisorctl start check12306 supervisorctl stop check12306 supervisorctl restart check12306 #重启所有属于名为groupworker这个分组的进程  supervisorctl start groupworker supervisorctl stop groupworker supervisorctl restart groupworker #启、停、重启全部进程(不会载入最新的配置文件)  supervisorctl start all supervisorctl stop all supervisorctl restart all #重新加载配置文件.停止原有进程并按新的配置启动所有进程  supervisorctl reload #根据最新的配置文件,启动新配置或有改动的进程,配置没有改动的进程不会受影响而重启。  supervisorctl update #注意:显示用stop停止掉的进程，用reload或者update都不会自动重启

• 交互式

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[root@aaa blog.cheyo.net]# supervisorctl check12306 RUNNING pid 1256, uptime 0:01:47 supervisor> stop check12306 check12306: stopped supervisor> start check12306 check12306: started supervisor> status check12306 RUNNING pid 1258, uptime 0:00:04 supervisor> restart check12306 check12306: stopped check12306: started supervisor> status check12306 RUNNING pid 1259, uptime 0:00:02 supervisor>

上面讲了一下supervisored及supervisorctl的使用技巧。现在遇到的一个场景是有一个服务需要用它进行管理。那写restart的逻辑我们就得先判断supervisored进程是不是在了，然后再用ctl进行管理服务
那我们的脚本应该怎么写呢？

# source function library
. /etc/rc.d/init.d/functions

# source system settings
[ -e /etc/sysconfig/supervisord ] && . /etc/sysconfig/supervisord

RETVAL=0

start() {
    echo "Starting supervisord: "
    if [ -e $PIDFILE ]; then
        echo "ALREADY STARTED"
        return 1
    fi

    # start supervisord with options from sysconfig (stuff like -c)
    /usr/bin/supervisord $OPTIONS

    # show initial startup status
    /usr/bin/supervisorctl $OPTIONS status

    # only create the subsyslock if we created the PIDFILE
    [ -e $PIDFILE ] && touch /var/lock/subsys/supervisord
}

stop() {
    echo -n "Stopping supervisord: "
    /usr/bin/supervisorctl $OPTIONS shutdown
    if [ -n "$WAIT_FOR_SUBPROCESSES" ]; then
        echo "Waiting roughly 60 seconds for $PIDFILE to be removed after child processes exit"
        for sleep in  2 2 2 2 4 4 4 4 8 8 8 8 last; do
            if [ ! -e $PIDFILE ] ; then
                echo "Supervisord exited as expected in under $total_sleep seconds"
                break
            else
                if [[ $sleep -eq "last" ]] ; then
                    echo "Supervisord still working on shutting down. We've waited roughly 60 seconds, we'll let it do its thing from here"
                    return 1
                else
                    sleep $sleep
                    total_sleep=$(( $total_sleep + $sleep ))
                fi

            fi
        done
    fi

    # always remove the subsys. we might have waited a while, but just remove it at this point.
    rm -f /var/lock/subsys/supervisord
}

restart() {
        stop
        start
}

case "$1" in
    start)
        start
        RETVAL=$?
        ;;
    stop)
        stop
        RETVAL=$?
        ;;
    restart|force-reload)
        restart
        RETVAL=$?
        ;;
    reload)
        /usr/bin/supervisorctl $OPTIONS reload
        RETVAL=$?
        ;;
    condrestart)
        [ -f /var/lock/subsys/supervisord ] && restart
        RETVAL=$?
        ;;
    status)
        /usr/bin/supervisorctl $OPTIONS status
        RETVAL=$?
        ;;
    *)
        echo $"Usage: $0 {start|stop|status|restart|reload|force-reload|condrestart}"
        exit 1
esac

exit $RETVAL

这个是启动superviord的服务。需要进一步改成supervisorctl的方式进行处理