Monit : 开源监控工具介绍

· Monit 简介

　　Monit是一个轻量级(500KB)跨平台的用来监控Unix/linux系统的开源工具。部署简单，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、文件、文件系统、网络状态（HTTP/SMTP等协议）、远程主机、服务器资源变化等等。 并且可以设定资源变化后需要做的动作，比如服务失败后自动重启，邮件告警等等。

　　Monit内置了WEB UI，可以一目了然地了解监控项的情况。Monit是监控本机服务的工具，M/Monit是其配套产品用以对Monit统一管理，但是M/Monit并不是开源的，需要购买。

　　本文我们介绍在CentOS7.3上部署Monit用来监控进程状态，并实现服务失败后自动重启以及邮件告警通知的功能。监控其他资源的方法在默认配置文件中都有举例这里不一一介绍。

　　Monit官网：https://mmonit.com/monit

　　Monit手册：https://mmonit.com/monit/documentation/monit.html

· Monit 安装

# rpm -ivh http://dl.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm# yum install -y monit

·Monit 常用命令

monit -t # 配置文件检测monit # 启动monit daemonmonit -c /var/monit/monitrc # 启动monit daemon时指定配置文件monit reload # 重新加载配置文件monit status # 查看所有监控项务状态monit status nginx # 查看nginx服务状态monit stop all # 停止所有服务，这里需要注意的是，如果开启了自动重启功能，停止某个被监控的服务必须用monit stop xxx，若用系统命令停止服务，Monit会自动再把服务起来。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

·Monit 配置文件

　　/etc/monit.conf 主配置文件

　　/etc/monit.d/ 各项服务单独配置文件路径，在主配置文件中将其include进来。

　　/etc/monit.conf 举例说明：

　　　　配置文件关键字：'if', 'and', 'with(in)', 'has', 'us(ing|e)', 'on(ly)', 'then', 'for', 'of'

################################################################################# 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):#
# 设置检测周期30sset 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#
#设置log路径，这里默认记录到syslogset logfile 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 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#
# 设置邮件服务器用来发送邮件告警通知 set mailserver mail.abcd.so### 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 informations about M/Monit ## see http://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.## set mmonit http://monit:monit@192.168.1.10:8080/collector#  # and register without credentials  # Don't register credentials#### Monit by default uses the following format for alerts if the the mail-format## statement is missing::## --8<--
# 设置邮件告警通知格式
 set mail-format {  from: 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.#
# 设置邮件告警通知人，Monit默认会通知monit进程本身的变化情况，如果不想收到monit进程自身的通知，加上but not on {instance}配置 set alert weian@abcd.so but not on { instance }     # 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 weian@abcd.so #### 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. #
# 设置UI界面访问信息set httpd port 2812 and use address 10.2.2.28 # only accept connection from localhost# allow localhost  # allow localhost to connect to the server and allow admin:monit  # require user 'admin' with password 'monit'################################################################################# 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 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 loadavg(5min) greater than 10 for 8 cycles then stop# if failed host www.tildeslash.com port 80 protocol http #  and request "/somefile.html"# then restart# if failed port 443 type tcpssl protocol http#  with timeout 15 seconds# then restart# if 3 restarts within 5 cycles then unmonitor# depends on apache_bin# group server# 
# 监控进程可以通过上面监控pid文件的方式，当没有pid文件时，可以通过MATCHING正则表达式来匹配进程。
# 测试一个进程是否匹配来自命令行使用的模式monit procmatch "regex-pattern"，这将列出匹配或不匹配的所有进程，regex模式。
# 我们这里监控了包含shop-pad-server字段的进程，并指明了启动以及停止的命令，这样在进程因故断掉后，Monit会自动重启进程。
# 同时若进程ID变动，会发送邮件通知到之前指定的收件人。

 check process shop-pad-server with MATCHING shop-pad-server  start program = "/usr/bin/nohup /home/azureuser/pad-server/run.sh > /home/azureuser/pad-server/nohup.out 2>&1 &"  stop program = "/usr/bin/ps -ef | /usr/bin/grep shop-pad| /usr/bin/grep -v grep | /usr/bin/awk '{print $2}' | xargs kill"  if changed pid then alert

# ## Check filesystem permissions, uid, gid, space and inode usage. 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# 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 upload > 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/*## 导入其他单项服务的监控配置# Include all files from /etc/monit.d/include /etc/monit.d/*

· 通知周期设置

　
Monit默认情况下如果一个服务失败只发送一个通知：　　alert foo@bar
　
如果您希望在服务保持处于失败状态时每十个周期通知一次，您可以使用：　　alert foo@bar with reminder on 10 cycles
　
同样，如果您想在每个失败的周期获得通知，您可以使用：　　alert foo@bar with reminder on 1 cycle

要禁止某些用户和服务的警报，可以在服务检查的局部配置里添加语句：　　noalert mail-address

·  服务检测周期设置

可以使用every语句修改服务检查计划。1.轮询周期倍数EVERY [number] CYCLES2.Cron-styleEVERY [cron]# [cron]# * * * * *# 分 时 日 月 周3.与Cron-style相反（do-not-check）NOT EVERY [cron]示例：示例1：每两个周期检查一次check process nginx with pidfile /var/run/nginx.pidevery 2 cycles示例2：在上午8点到下午7点之间检查每个工作日check program checkOracleDatabasewith path /var/monit/programs/checkoracle.plevery "* 8-19 * * 1-5"示例3：在星期日0AM到3AM之间不要在备份窗口中运行检查，否则运行具有常规轮询周期频率的检查。check process mysqld with pidfile /var/run/mysqld.pidnot every "* 0-3 * * 0"注意不要使用特定的分钟，因为Monit可能不会在那分钟运行。

· WEB UI界面

参考：

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

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原标题：Monit : 开源监控工具介绍

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