【开源服务器监控工具Monit】

Monit是一款功能非常丰富的进程、文件、目录和设备的监测软件，适用于Linux/Unix平台。 它可以自动修复那些已经停止运作的程序,特使适合处理那些由于多种原因导致的软件错误，同时Monit 包含一个内嵌的 HTTP(S) Web 界面，你可以使用浏览器方便地查看 Monit 所监视的服务器。Monit是一款功能非常丰富的进程、文件、目录和设备的监测软件,用于Unix平台。 它可以自动修复那些已经停止运作的程序,特使适合处理那些由于多种原因导致的软件错误。monit运行于应用层。Monit特别易于安装，而且非常轻量级（只有500KB大小），并且不依赖任何第三方程序、插件或者库。Monit可以监控服务器进程状态、HTTP/TCP状态码、服务器资源变化、文件系统变动等等，根据这些变化，可以设定邮件报警、重启进程或服务。易于安装、轻量级的实现以及强大的功能，让Monit成为一个理想的后备监控工具。

 

 

What Monit can do

Proactive adj. 积极主动的; 前摄的; 主动出击的; 先发制人的;

Monit can act if an error situation should occur, e.g.; if sendmail is not running, Monit can start sendmail again automatically or if apache is using too much resources (e.g. if a DoS attack is in progress) Monit can stop or restart apache and send you an alert message. Monit can also monitor process characteristics, such as; how much memory or cpu cycles a process is using.

 

Processes

You can use Monit to monitor daemon processes or similar programs running on localhost. Monit is particularly useful for monitoring daemon processes, such as those started at system boot time from /etc/init/ For instance sendmail, sshd, apache and mysql.

 

Files, Dirs and Filesystems

You can also use Monit to monitor files, directories and filesystems on localhost. Monit can monitor these items for changes, such as timestamps changes, checksum changes or size changes. This is also useful for security reasons - you can monitor the md5 or sha1 checksum of files that should not change and get an alert or perform an action if they should change.

 

Cloud and Hosts

Monitor network connections to various servers, either on localhost or on remote hosts. TCP, UDP and Unix Domain Sockets are supported. Network tests can be performed on a protocol level; Monit has built-in tests for the main Internet protocols, such as HTTP, SMTP etc. Even if a protocol is not supported you can still test the server as you can configure Monit to send any data and test the response from the server.

 

Programs and scripts

Monit can be used to test programs or scripts at certain times, much like cron, but in addition, you can test the exit value of a program and perform an action or send an alert if the exit value indicates an error. This means that you can use Monit to perform any type of check you can write a script for.

 

System

Finally, Monit can be used to monitor general system resources on localhost such as overall CPU usage, Memory and Load Average.

 

 

下面是一个简单的例子，配置文件中已经包含了大量的例子，可以看配置文件参考。

 

set daemon  120        #设置检测时间

set logfile /var/log/monit.log        #monit日志

set alert www@vpser.net with reminder on 1 cycle  #出现1次错误的时候发报警邮件到指定的邮箱

set mailserver mail.vpser.net     #设置邮件服务器

set httpd port 2812 and            # 设置http监控页面的端口

     use address 74.207.246.99   # http监控页面的IP

     allow localhost               # 允许本地访问

     allow 123.23.45.0/24           # 允许此IP段访问

     #allow 0.0.0.0/0.0.0.0       # 允许所有IP访问

     allow username:password     #设置访问用户名密码

 

#检测sshd服务

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

   start program  "/etc/init.d/sshd start"

   stop program  "/etc/init.d/sshd stop"

   if failed port 22 protocol ssh then restart

   if 5 restarts within 5 cycles then timeout

 

#检测mysql服务

check process mysql with pidfile /usr/local/mysql/var/vpser.pid

   group database

   start program = "/etc/init.d/mysql start"

   stop program = "/etc/init.d/mysql stop"

   if failed host 127.0.0.1 port 3306 then restart

   if 5 restarts within 5 cycles then timeout

 

#检测nginx服务

 check process nginx with pidfile /usr/local/nginx/logs/nginx.pid

    start program = "/etc/init.d/nginx start"

    stop program  = "/etc/init.d/nginx stop"

    if failed host www.vpser.net port 80 protocol http

       then restart

配置中的pid及启动、关闭脚本的路径一定要是全路径，且参数一定要正确否则会造成无法正常检测或正常启动。