监控进程

发表于2015-02-11

有时候,进程突然终止服务,可能是没有资源了,也可能是意外,比如说: 因为 OOM 被杀;或者由于 BUG 导致崩溃;亦或者误操作等等,此时,我们需要重新启动进程。

实际上,Linux 本身的初始化系统能实现简单的功能,无论是老牌的 SysVinit,还是新潮的 Upstart 或者 Systemd 均可,但它们并不适合处理一些复杂的情况,比如说: CPU 占用超过多少就重启;或者同时管理 100 个 PHP 实现的 Worker 进程等等,如果你有类似的需求,那么可以考虑试试 Monit 和 Supervisor,相信会有不一样的感受。

让我们看看 Monit 的用法,假设我们要监控 Nginx 进程,一旦其 CPU 使用率连续 5 次轮询周期里均超过 50% 的话,就重启进程,此时就可以按照如下方式设置:

check process nginx with pidfile /var/run/nginx.pid

start program = “/etc/init.d/nginx start”

stop program = “/etc/init.d/nginx stop”

if cpu is greater than 50% for 5 cycles then restart

monit -t # 配置文件检测

monit # 启动monit daemon

monit -c /var/monit/monitrc # 启动monit daemon时指定配置文件

monit reload # 当更新了配置文件需要重载

monit status # 查看所有服务状态

monit status nginx # 查看nginx服务状态

monit stop all # 停止所有服务

monit stop nginx # 停止nginx服务

monit start all # 启动所有服务

monit start nginx # 启动nginx服务

monit -V # 查看版本

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# install monit
pacman -S monit

Install EPEL Repository
yum install monit

# edit config file
emacs /etc/monitrc
# and uncomment line include /etc/monit.d/*

#create monit conifg file
emacs /etc/monit.d/foo

#add following lines

#check process projectFoo matching projectFoo
#      start program "/usr/bin/systemctl start projectFoo.service"
#      if failed port 8081 protocol ssh then restart
#      if 5 restarts within 5 cycles then timeout

echo "check host tomcat with address localhost
 stop program = "/etc/init.d/tomcat stop"
 start program = "/etc/init.d/tomcat restart"
 if failed port 8080 and protocol http
 then start
" > /etc/monit.d/tomcat 
/etc/init.d/monit restart

#reload monit conifg or restart monit

官网

https://mmonit.com/

https://blog.huoding.com/2015/02/11/419

https://linux.cn/article-5542-2.html

https://wiki.archlinux.org/index.php/Monit

https://mmonit.com/monit/documentation/monit.html#NAME

<a href="https://blog.rimuhosting.com/2011/01/27/setting-up-monit-with-tomcat/">Setting up Monit + with tomcat</a>

https://blog.rimuhosting.com/2011/01/27/setting-up-monit-with-tomcat/embed/#?secret=8QoE16qN7b