Monit 官网：https://mmonit.com/monit/
一、Monit 介绍
Monit是用于管理和监视Unix系统上的进程，程序，文件，目录和文件系统的实用程序。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因果操作。例如，Monit可以在不运行的情况下启动进程，在不响应的情况下重启进程，在使用过多资源的情况下停止进程。您可以使用Monit监视文件，目录和文件系统的更改，例如时间戳更改，校验和更改或大小更改。
Monit通过基于自由格式，面向令牌的语法的易于配置的控制文件进行控制。Monit记录到syslog或自己的日志文件中，并通过可自定义的警报消息通知您有关错误情况的信息。Monit可以执行各种TCP / IP网络检查，协议检查，并且可以使用SSL进行此类检查。Monit提供HTTP（S）接口，您可以使用浏览器访问Monit程序。
二、Monit 特色
- 超轻量, 稳定, 高可用
- 依赖少, 安装配置方便, 尽量减少运维及学习成本(即使没有任何 Monit 基础的人, 都能轻易的读懂大部分监控文件)
- 非侵入式, 被监控的程序可以不用知道监控程序的存在(如果使用 Supervisor 监控, 则服务必须从 Supervisor 启动)
- 基本功能完备(进程 、文件 、Fifo、 文件系统、目录、远程主机、系统、程序 、网络
9 种类型监控, 邮件报警, 支持用户自定义 shell 扩展)
三、Monit 和 Supervisor 的对比
进程守护
-
supervisor：
优点：采用托管的方式守护，一旦进程异常能马上检查出来，可以指定目录，对启动命令本身修改不大缺点：只能启动前台进程，一旦supervisor发生重启会再次启动进程，导致进程再次被启动（不知道有没有办法避免，）
-
monit：
优点：有基于pid文件和正则匹配的检查进程，不会导致进程重复启动缺点：通过定时检查的方式检查进程，存在一定延时，另外启动命令必须要包含完整的路径
提醒
- supervisor：需要使用第三方插件才能实现邮件提醒功能，本身并不支持邮件提醒
- monit：原生支持邮件提醒功能
磁盘监控
- supervisor：本身只是为了守护进程，所以需要第三方扩展才可以监控磁盘
- monit：原生支持磁盘监控
轻量级占用少
- supervisor：基于Python开发，轻量级
- monit：轻量级
其他
2款软件都提供了网页管理的功能，monit能在页面中直接对进程进行重启，停止和启动操作，supervisor能直接在页面中查看软件输出的日志
四、Monit 使用
命令行
Usage: monit [options]+ [command]
选项
Monit可以识别以下选项。但是，建议您直接在.monitrc控制文件中设置选项（如果适用）
-c file 文件使用此控制文件
-d n 每n秒一次将 Monit 作为守护程序运行。或在monitrc中使用“ set daemon”
-g name 设置用于启动，停止，重新启动，监视，取消监视，状态和摘要操作的组名
-l logfile 将日志信息打印到此文件。或在monitrc中使用“设置日志”
-p pidfile 在守护程序模式下使用此锁定文件。或在monitrc中使用“ set pidfile”
-s statefile 将状态信息写入此文件。或在monitrc中使用“设置状态文件”
-I 不要在后台模式下运行（需要从init运行）。或在monitrc中使用“ set init”
--id 打印Monit的唯一ID
--resetid 重置Monit的唯一ID。谨慎使用
-B 批处理命令行模式（无表格输出，无颜色）。或在monitrc中使用“设置终端批处理”
-t 运行控制文件的语法检查
-v 详细模式（诊断输出）
-vv 非常详细的模式，与-v相同，并在错误时记录日志堆栈跟踪
-H [filename] 如果省略文件名，则打印文件或标准输入的MD5和SHA1散列；Monit之后将退出
-V 打印版本号和补丁程序级别
-h 打印帮助文本
参数:
将Monit作为守护进程运行后，可以使用以下参数之一调用Monit。
然后，Monit将连接到Monit守护程序（默认情况下位于TCP端口127.0.0.1:2812上），
并要求Monit守护程序执行所请求的操作。换一种说法; 调用不带参数的monit将启动Monit守护程序，
而带参数的monit则使您能够与Monit守护进程进行通信。
start all 启动控制文件中列出的所有服务，并启用对它们的监视。如果设置了组选项（-g），则仅启动并启用对已命名组中服务的监视（在这种情况下，不需要“ all”）
start <name> 启动命名服务并启用对其的监视。该名称是monitrc文件中的服务条目名称
stop all 停止控制文件中列出的所有服务并禁用其监视。如果设置了组选项，则仅停止和禁用对命名组中服务的监视（在这种情况下，不需要“全部”）
stop <name> 停止命名服务并禁用其监视。该名称是monitrc文件中的服务条目名称
restart all 停止并启动所有服务。如果设置了组选项，则仅重新启动命名组中的服务（在这种情况下，不需要“全部”）
restart <name> 重新启动命名服务。该名称是monitrc文件中的服务条目名称
monitor all 启用监视控制文件中列出的所有服务。如果设置了组选项，则仅开始监视命名组中的服务（在这种情况下，不需要“全部”）
monitor <name> 启用监视命名服务。该名称是monitrc文件中的服务条目名称。Monit还可以监视该服务所依赖的所有服务
unmonitor all 禁用监视控制文件中列出的所有服务。如果设置了组选项，则仅禁用监视命名组中的服务（在这种情况下，不需要“全部”）
unmonitor <name> 禁用对命名服务的监视。该名称是monitrc文件中的服务条目名称。Monit还将禁用对依赖此服务的所有服务的监视
reload 重新初始化正在运行的Monit守护程序，该守护程序将重新读取其配置，关闭并重新打开日志文件
status [name] 打印服务状态信息
summary [name] 打印简短的状态摘要
report [up|down|..] 报告服务状态。脚本可以轻松解析输出。如果没有选项，则打印由Monit管理的所有服务的状态的简短概述。该选项up打印此状态下所有服务的数量，同样打印down等等
quit 终止Monit守护进程
validate 检查控制文件中列出的所有服务。当Monit在守护程序模式下运行时，此操作也是默认行为
procmatch <pattern> 允许轻松测试模式以进行过程匹配检查。该命令将正则表达式作为参数，并显示所有与模式匹配的正在运行的进程
配置文件
###############################################################################
## Monit control file
###############################################################################
##
## Comments begin with a '#' and extend through the end of the line. Keywords
## are case insensitive. All path's MUST BE FULLY QUALIFIED, starting with '/'.
##
## Below you will find examples of some frequently used statements. For
## information about the control file and a complete list of statements and
## options, please have a look in the Monit manual.
##
##
###############################################################################
## Global section
###############################################################################
##
## Start Monit in the background (run as a daemon):
#
set daemon 30 # check services at 30 seconds intervals
# with start delay 240 # optional: delay the first check by 4-minutes (by
# # default Monit check immediately after Monit start)
#
#
## Set syslog logging. If you want to log to a standalone log file instead,
## specify the full path to the log file
#
set log syslog
#
#
## Set the location of the Monit lock file which stores the process id of the
## running Monit instance. By default this file is stored in $HOME/.monit.pid
#
# set pidfile /var/run/monit.pid
#
## Set the location of the Monit id file which stores the unique id for the
## Monit instance. The id is generated and stored on first Monit start. By
## default the file is placed in $HOME/.monit.id.
#
# set idfile /var/.monit.id
#
## Set the location of the Monit state file which saves monitoring states
## on each cycle. By default the file is placed in $HOME/.monit.state. If
## the state file is stored on a persistent filesystem, Monit will recover
## the monitoring state across reboots. If it is on temporary filesystem, the
## state will be lost on reboot which may be convenient in some situations.
#
# set statefile /var/.monit.state
#
#
## Set limits for various tests. The following example shows the default values:
##
# set limits {
# programOutput: 512 B, # check program's output truncate limit
# sendExpectBuffer: 256 B, # limit for send/expect protocol test
# fileContentBuffer: 512 B, # limit for file content test
# httpContentBuffer: 1 MB, # limit for HTTP content test
# networkTimeout: 5 seconds # timeout for network I/O
# programTimeout: 300 seconds # timeout for check program
# stopTimeout: 30 seconds # timeout for service stop
# startTimeout: 30 seconds # timeout for service start
# restartTimeout: 30 seconds # timeout for service restart
# }
## Set global SSL options (just most common options showed, see manual for
## full list).
#
# set ssl {
# verify : enable, # verify SSL certificates (disabled by default but STRONGLY RECOMMENDED)
# selfsigned : allow # allow self signed SSL certificates (reject by default)
# }
#
#
## Set the list of mail servers for alert delivery. Multiple servers may be
## specified using a comma separator. If the first mail server fails, Monit
# will use the second mail server in the list and so on. By default Monit uses
# port 25 - it is possible to override this with the PORT option.
#
# set mailserver mail.bar.baz, # primary mailserver
# backup.bar.baz port 10025, # backup mailserver on port 10025
# localhost # fallback relay
#
#
## By default Monit will drop alert events if no mail servers are available.
## If you want to keep the alerts for later delivery retry, you can use the
## EVENTQUEUE statement. The base directory where undelivered alerts will be
## stored is specified by the BASEDIR option. You can limit the queue size
## by using the SLOTS option (if omitted, the queue is limited by space
## available in the back end filesystem).
#
# set eventqueue
# basedir /var/monit # set the base directory where events will be stored
# slots 100 # optionally limit the queue size
#
#
## Send status and events to M/Monit (for more information about M/Monit
## see https://mmonit.com/). By default Monit registers credentials with
## M/Monit so M/Monit can smoothly communicate back to Monit and you don't
## have to register Monit credentials manually in M/Monit. It is possible to
## disable credential registration using the commented out option below.
## Though, if safety is a concern we recommend instead using https when
## communicating with M/Monit and send credentials encrypted. The password
## should be URL encoded if it contains URL-significant characters like
## ":", "?", "@". Default timeout is 5 seconds, you can customize it by
## adding the timeout option.
#
# set mmonit http://monit:monit@192.168.1.10:8080/collector
# # with timeout 30 seconds # Default timeout is 5 seconds
# # and register without credentials # Don't register credentials
#
#
## Monit by default uses the following format for alerts if the mail-format
## statement is missing::
## --8<--
## set mail-format {
## from: Monit <monit@$HOST>
## subject: monit alert -- $EVENT $SERVICE
## message: $EVENT Service $SERVICE
## Date: $DATE
## Action: $ACTION
## Host: $HOST
## Description: $DESCRIPTION
##
## Your faithful employee,
## Monit
## }
## --8<--
##
## You can override this message format or parts of it, such as subject
## or sender using the MAIL-FORMAT statement. Macros such as $DATE, etc.
## are expanded at runtime. For example, to override the sender, use:
#
# set mail-format { from: monit@foo.bar }
#
#
## You can set alert recipients whom will receive alerts if/when a
## service defined in this file has errors. Alerts may be restricted on
## events by using a filter as in the second example below.
#
# set alert sysadm@foo.bar # receive all alerts
#
## Do not alert when Monit starts, stops or performs a user initiated action.
## This filter is recommended to avoid getting alerts for trivial cases.
#
# set alert your-name@your.domain not on { instance, action }
#
#
## Monit has an embedded HTTP interface which can be used to view status of
## services monitored and manage services from a web interface. The HTTP
## interface is also required if you want to issue Monit commands from the
## command line, such as 'monit status' or 'monit restart service' The reason
## for this is that the Monit client uses the HTTP interface to send these
## commands to a running Monit daemon. See the Monit Wiki if you want to
## enable SSL for the HTTP interface.
#
set httpd port 2812 and
use address localhost # only accept connection from localhost (drop if you use M/Monit)
allow localhost # allow localhost to connect to the server and
allow admin:monit # require user 'admin' with password 'monit'
#with ssl { # enable SSL/TLS and set path to server certificate
# pemfile: /etc/ssl/certs/monit.pem
#}
###############################################################################
## Services
###############################################################################
##
## Check general system resources such as load average, cpu and memory
## usage. Each test specifies a resource, conditions and the action to be
## performed should a test fail.
#
# check system $HOST
# if loadavg (1min) per core > 2 for 5 cycles then alert
# if loadavg (5min) per core > 1.5 for 10 cycles then alert
# if cpu usage > 95% for 10 cycles then alert
# if memory usage > 75% then alert
# if swap usage > 25% then alert
#
#
## Check if a file exists, checksum, permissions, uid and gid. In addition
## to alert recipients in the global section, customized alert can be sent to
## additional recipients by specifying a local alert handler. The service may
## be grouped using the GROUP option. More than one group can be specified by
## repeating the 'group name' statement.
#
# check file apache_bin with path /usr/local/apache/bin/httpd
# if failed checksum and
# expect the sum 8f7f419955cefa0b33a2ba316cba3659 then unmonitor
# if failed permission 755 then unmonitor
# if failed uid "root" then unmonitor
# if failed gid "root" then unmonitor
# alert security@foo.bar on {
# checksum, permission, uid, gid, unmonitor
# } with the mail-format { subject: Alarm! }
# group server
#
#
## Check that a process is running, in this case Apache, and that it respond
## to HTTP and HTTPS requests. Check its resource usage such as cpu and memory,
## and number of children. If the process is not running, Monit will restart
## it by default. In case the service is restarted very often and the
## problem remains, it is possible to disable monitoring using the TIMEOUT
## statement. This service depends on another service (apache_bin) which
## is defined above.
#
# check process apache with pidfile /usr/local/apache/logs/httpd.pid
# start program = "/etc/init.d/httpd start" with timeout 60 seconds
# stop program = "/etc/init.d/httpd stop"
# if cpu > 60% for 2 cycles then alert
# if cpu > 80% for 5 cycles then restart
# if totalmem > 200.0 MB for 5 cycles then restart
# if children > 250 then restart
# if disk read > 500 kb/s for 10 cycles then alert
# if disk write > 500 kb/s for 10 cycles then alert
# if failed host www.tildeslash.com port 80 protocol http and request "/somefile.html" then restart
# if failed port 443 protocol https with timeout 15 seconds then restart
# if 3 restarts within 5 cycles then unmonitor
# depends on apache_bin
# group server
#
#
## Check filesystem permissions, uid, gid, space usage, inode usage and disk I/O.
## Other services, such as databases, may depend on this resource and an automatically
## graceful stop may be cascaded to them before the filesystem will become full and data
## lost.
#
# check filesystem datafs with path /dev/sdb1
# start program = "/bin/mount /data"
# stop program = "/bin/umount /data"
# if failed permission 660 then unmonitor
# if failed uid "root" then unmonitor
# if failed gid "disk" then unmonitor
# if space usage > 80% for 5 times within 15 cycles then alert
# if space usage > 99% then stop
# if inode usage > 30000 then alert
# if inode usage > 99% then stop
# if read rate > 1 MB/s for 5 cycles then alert
# if read rate > 500 operations/s for 5 cycles then alert
# if write rate > 1 MB/s for 5 cycles then alert
# if write rate > 500 operations/s for 5 cycles then alert
# if service time > 10 milliseconds for 3 times within 5 cycles then alert
# group server
#
#
## Check a file's timestamp. In this example, we test if a file is older
## than 15 minutes and assume something is wrong if its not updated. Also,
## if the file size exceed a given limit, execute a script
#
# check file database with path /data/mydatabase.db
# if failed permission 700 then alert
# if failed uid "data" then alert
# if failed gid "data" then alert
# if timestamp > 15 minutes then alert
# if size > 100 MB then exec "/my/cleanup/script" as uid dba and gid dba
#
#
## Check directory permission, uid and gid. An event is triggered if the
## directory does not belong to the user with uid 0 and gid 0. In addition,
## the permissions have to match the octal description of 755 (see chmod(1)).
#
# check directory bin with path /bin
# if failed permission 755 then unmonitor
# if failed uid 0 then unmonitor
# if failed gid 0 then unmonitor
#
#
## Check a remote host availability by issuing a ping test and check the
## content of a response from a web server. Up to three pings are sent and
## connection to a port and an application level network check is performed.
#
# check host myserver with address 192.168.1.1
# if failed ping then alert
# if failed port 3306 protocol mysql with timeout 15 seconds then alert
# if failed port 80 protocol http
# and request /some/path with content = "a string"
# then alert
#
#
## Check a network link status (up/down), link capacity changes, saturation
## and bandwidth usage.
#
# check network public with interface eth0
# if failed link then alert
# if changed link then alert
# if saturation > 90% then alert
# if download > 10 MB/s then alert
# if total uploaded > 1 GB in last hour then alert
#
#
## Check custom program status output.
#
# check program myscript with path /usr/local/bin/myscript.sh
# if status != 0 then alert
#
#
###############################################################################
## Includes
###############################################################################
##
## It is possible to include additional configuration parts from other files or
## directories.
#
# include /etc/monit.d/*
#
参考资料
https://www.jianshu.com/p/248d6456e83f
https://www.jianshu.com/p/b4a7b209f11a
https://www.cnblogs.com/52fhy/p/6412547.html
