Monit是一个跨平台的用来监控Unix/linux系统（比如Linux、BSD、OSX、Solaris）的工具。Monit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成为一个理想的监控工具。
在中小企业中，还没有能力自主开发相应的监控工具，可以考虑使用Monit。
配置文件
主配置文件
该文件中主要是monit的主要配置信息。
文件位置：/etc/monit/monitrc
root@53dea2366136:/etc/monit# cat monitrc
###############################################################################
## 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 120 # check services at 2-minute 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 /var/log/monit.log
#
#
## 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 idfile /var/lib/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/lib/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/lib/monit/events # 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 informations 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:[email protected]: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
## 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: [email protected] }
#
#
## 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 [email protected] # 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 [email protected] 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
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) > 4 then alert
# if loadavg (5min) > 2 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 [email protected] 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 loadavg(5min) greater than 10 for 8 cycles then stop
# 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/conf.d/*
include /etc/monit/conf-enabled/*
#
服务配置
在conf.d文件夹中可以单独配置各项服务。
文件夹：/etc/monit/conf.d/
root@53dea2366136:/etc/monit/conf.d# cat spawn-fcgi.conf
# 该配置文件是 监听9001端口的pid文件
check process spawn-fcgi-9001 with pidfile /var/run/scan.9001.pid
#9001端口服务启动命令
start program = "/light_keypoints/scan/start.sh 9001"
#在5个周期内重启三次的话，就不再监控该服务
if 3 restarts within 5 cycles then unmonitor
服务启动
启动Monit服务
root@53dea2366136:/etc/monit/conf.d# service monit start
* Starting daemon monitor monit [ OK ]
查看Monit监控服务状态
root@53dea2366136:/etc/monit/conf.d# monit status
Monit 5.25.1 uptime: 0m
Process 'spawn-fcgi-9001'
status Does not exist
monitoring status Monitored
monitoring mode active
on reboot start
data collected Tue, 10 Mar 2020 08:01:45
System '53dea2366136'
status OK
monitoring status Monitored
monitoring mode active
on reboot start
load average [0.00] [0.02] [0.00]
cpu 0.0%us 0.0%sy 0.0%wa
memory usage 337.3 MB [4.2%]
swap usage 0 B [0.0%]
uptime 6d 23h 37m
boot time Tue, 03 Mar 2020 08:24:40
data collected Tue, 10 Mar 2020 08:01:45
启动所有监控服务
root@53dea2366136:/etc/monit/conf.d# monit start all
查看所有监控服务状态
root@53dea2366136:/etc/monit# monit status
Monit 5.25.1 uptime: 9h 30m
Process 'spawn-fcgi-9001'
status OK
monitoring status Monitored
monitoring mode active
on reboot start
pid 435
parent pid 1
uid 0
effective uid 0
gid 0
uptime 9h 22m
threads 1
children 0
cpu 0.0%
cpu total 0.0%
memory 0.1% [7.0 MB]
memory total 0.1% [7.0 MB]
security attribute (null)
disk read 0 B/s [272 kB total]
data collected Wed, 11 Mar 2020 04:02:13
System '53dea2366136'
status OK
monitoring status Monitored
monitoring mode active
on reboot start
load average [0.00] [0.00] [0.00]
cpu 0.1%us 0.4%sy 0.0%wa
memory usage 338.3 MB [4.2%]
swap usage 0 B [0.0%]
uptime 7d 19h 38m
boot time Tue, 03 Mar 2020 08:24:40
data collected Wed, 11 Mar 2020 04:02:13
常用命令
# 配置文件检测
monit -t
# 启动monit 服务 daemon
service monit start
# 启动monit daemon时指定配置文件
monit -c /var/monit/monitrc
# 当更新了配置文件需要重载
monit reload
# 查看所有服务状态
monit status
# 查看某个服务状态
monit status someone
# 启动所有服务
monit start all
# 启动某个服务
monit start someone
# 停止所有服务
monit stop all
# 停止某个服务
monit stop someone
monit -V # 查看版本