如何配置monit监控某个进程？

假设我们要监控 myproc 进程
创建一个新文件/etc/monit/conf-available/myproc：

$ sudo vi /etc/monit/conf-available/myproc

内容如下：

check process myproc
        matching "myproc"
        start program = "/etc/init.d/myproc start"
        stop program = "/usr/bin/killall myproc"

启用该监控项：

$ sudo ln -s /etc/monit/conf-available/myproc /etc/monit/conf-enabled/

检查monit配置文件的语法：

$ monit -t

重新加载monit，使新加配置文件生效：

$ sudo /etc/init.d/monit reload

或者

$ sudo systemctl reload monit

当myproc异常终止后，monit将重启它，并发送邮件。

如何在系统启动时启用monit服务？

执行以下命令：

$ sudo systemctl enable monit

如何查看Monit信息？

查看Monit总览信息

$ sudo monit summary

输出示例：

The Monit daemon 5.16 uptime: 1h 9m 

Process 'openvpn'                   Running
File 'openvpn_bin'                  Accessible
System 'blr-onitroad-do-0001'       Running

查看monit运行的状态：

$ sudo monit status

查看nginx进程的信息

$ sudo monit status nginx

Monit

Monit是一个免费的开源软件，可用于监控进程。它可以重启失败服务。
Monit是用于管理和监视Unix系统的小型开源实用程序。 Monit会进行自动维护和修复，并且可以在错误情况下执行有意义的操作。如果发生错误情况，例如，Monit可以采取行动。如果sendmail未运行，则Monit可以自动再次启动sendmail，或者apache使用的资源过多(例如，正在进行DoS攻击)，Monit可以停止或重启apache并向您发送警报消息。

如何配置Monit来监控Apache服务器？

配置文件：

$ cat /etc/monit/conf-available/apache2

输出示例：

check process apache with pidfile /var/run/apache2/apache2.pid
   group www
   group apache
   start program = "/etc/init.d/apache2 start"
   stop program  = "/etc/init.d/apache2 stop"
   if 4 restarts within 20 cycles then timeout
   if failed host localhost port 80 with protocol http and request "/server-status" with timeout 25 seconds for 4 times within 5 cycles then restart
   depend apache_bin
   depend apache_rc
 
check file apache_bin with path /usr/sbin/apache2
   group apache
   include /etc/monit/templates/rootbin
 
check file apache_rc with path /etc/init.d/apache2
   group apache
   include /etc/monit/templates/rootbin

配置monit,监控MariaDB/MySQL服务

新建配置文件：

$ vi /etc/monit/conf-available/mysql

内容如下：

check process mysqld with pidfile /var/run/mysqld/mysqld.pid
   group database
   group mysql
   start program = "/etc/init.d/mysql start"
   stop  program = "/etc/init.d/mysql stop"
   if failed host localhost port 3306 protocol mysql with timeout 15 seconds for 3 times within 4 cycles then restart
   if failed unixsocket /var/run/mysqld/mysqld.sock protocol mysql for 3 times within 4 cycles then restart
   if 5 restarts with 5 cycles then timeout
   depend mysql_bin
   depend mysql_rc
 
check file mysql_bin with path /usr/sbin/mysqld
   group mysql
   include /etc/monit/templates/rootbin
 
check file mysql_rc with path /etc/init.d/mysql
   group mysql
   include /etc/monit/templates/rootbin

在Debian或Ubuntu Linux上如何监控Nginx/Apache这些服务，当它们由问题时自动重启？
如何使用Monit Debian服务，并在服务崩溃后重启服务？
如何在Debian或Ubuntu Linux上安装monit来监控进程？

如何配置Monit来监控OpenSSH SSHD服务器？

配置文件

$ cat /etc/monit/conf-available/openssh-server

输出示例：

check process sshd with pidfile /var/run/sshd.pid
   group system
   group sshd
   start program = "/etc/init.d/ssh start"
   stop  program = "/etc/init.d/ssh stop"
   if failed host localhost port 22 with proto ssh then restart
   if 5 restarts with 5 cycles then timeout
   depend on sshd_bin
   depend on sftp_bin
   depend on sshd_rc
   depend on sshd_rsa_key
   depend on sshd_dsa_key
 
check file sshd_bin with path /usr/sbin/sshd
   group sshd
   include /etc/monit/templates/rootbin
 
check file sftp_bin with path /usr/lib/openssh/sftp-server
   group sshd
   include /etc/monit/templates/rootbin
 
check file sshd_rsa_key with path /etc/ssh/ssh_host_rsa_key
   group sshd
   include /etc/monit/templates/rootstrict
 
check file sshd_dsa_key with path /etc/ssh/ssh_host_dsa_key
   group sshd
   include /etc/monit/templates/rootstrict
 
check file sshd_rc with path /etc/ssh/sshd_config
   group sshd
   include /etc/monit/templates/rootrc

必须使用ln命令链接这些文件，然后重新加载monit服务器。

$ cd /etc/monit/conf-enabled/
$ sudo ln -s /etc/monit/conf-available/nginx
$ sudo ln -s /etc/monit/conf-available/mysql
$ sudo ln -s /etc/monit/conf-available/apache2
$ sudo monit -t
$ sudo /etc/init.d/monit reload

如何查看Monit的日志？

monit 默认日志文件为/var/log/monit.log。

$ sudo tail -f /var/log/monit.log

通过浏览器查看Monit：

http://server1.onitroad.local:2812

安装monit

执行以下apt-get命令/apt命令：

$ sudo apt-get install monit

配置monit

• 主配置文件：/etc/monit/monitrc
• 进程/服务器对应配置文件的目录：/etc/monit/conf-available/和/etc/monit/conf-enabled /

编辑/etc/monit/monitrc：

$ sudo vi /etc/monit/monitrc

首先设置警报接收者的电子邮件地址：

set alert admin@your-domain-name-here

或者这样设置，只获取有关安全性的警报：

set alert security@your-domain-name-here on { checksum, permission, uid, gid }

请注意，默认情况下，monit在服务失败时只发送一封电子邮件通知，
而在服务恢复时则只发送一封电子邮件通知。

下面的设置，在服务失败时每五个周期就发送一次通知：

alert jack@server1.onitroad.local with reminder on 5 cycles

启用嵌入式HTTP接口。
用于查看monit的服务状态，并且可以通过Web界面管理服务：

set httpd port 2812 and
     use address localhost  # only accept connection from localhost
     allow localhost        # allow localhost to connect to the server and
     allow admin:monit      # require user 'admin' with password 'monit'

如何启动/停止/重启monit服务？

语法为：

$ sudo systemctl status monit
$ sudo systemctl stop monit
$ sudo systemctl restart monit
$ sudo systemctl start monit

如何配置Monit来监控Nginx服务器？

配置文件：

$ vi /etc/monit/conf-available/nginx

内容：

check process nginx with pidfile /var/run/nginx.pid
   group www
   group nginx
   start program = "/etc/init.d/nginx start"
   stop program = "/etc/init.d/nginx stop"
   if 5 restarts with 5 cycles then timeout
   depend nginx_bin
   depend nginx_rc

check file nginx_bin with path /usr/sbin/nginx
   group nginx
   include /etc/monit/templates/rootbin

check file nginx_rc with path /etc/init.d/nginx
   group nginx
   include /etc/monit/templates/rootbin