What is Monit

With the integrated monitoring daemon, you can perform email notification, automatic recovery, etc., and monitoring above the set threshold. -Http response, process, port monitoring Example) Apache, MySQL, SSL, Postfix, fluentd ・ CPU, memory, load average, disk capacity, etc.

1. 1. Initial setting (when newly installing on the server)

① Install and enable the EPEL rpm package

$ sudo yum install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm

② Install monit

$ sudo yum -y install monit

③ Check if there are related files

$ rpm -ql monit
/etc/logrotate.d/monit
/etc/monit.d
/etc/monit.d/logging
/etc/monitrc
/usr/bin/monit
/usr/lib/systemd/system/monit.service
/usr/share/doc/monit-5.14
/usr/share/doc/monit-5.14/COPYING
/usr/share/doc/monit-5.14/README
/usr/share/man/man1/monit.1.gz
/var/log/monit.log

④ Backup of configuration file

$ sudo cp -av /etc/monitrc{,.bk}
`/etc/monitrc' -> `/etc/monitrc.bak'
// -a Copy with permissions as much as possible
// -v Show file name before copying
// {,.bk}With a technique called brace deployment.Copy with file name bk

⑤ Edit the setting file

$ vi /etc/monitrc

…
set daemon  30              //The default check interval is 30 seconds, so change it arbitrarily.
…
include /etc/monit.d/*.conf // .Edit to read only conf

⑤'monit also has a WWW server function, which allows you to refer to settings and control services via HTTP.

set httpd port 2812 and    #Web interface port(Default:2812)
    allow localhost        #IP to allow access(localhost)
    allow XXX.XXX.XXX.XXX/XX  #IP to allow access(Any IP)
    allow admin:monit      #Management console user='admin' password='monit'
#Comment out because SSL is not used below
    #with ssl {            # enable SSL/TLS and set path to server certificate
    #    pemfile: /etc/ssl/certs/monit.pem
    #}

⑥ Creation of configuration file

$ vi /etc/monit.d/XXXX.conf　//Create new for each setting
$ mv /etc/monit.d/logging /etc/monit.d/logging.conf　//Rename log configuration file

2. Common configuration file

The following is the main configuration file.

/etc/monitrc
backup:/etc/monitrc.bk

Include and read the following individual configuration file.
/etc/monit.d/*.conf

3. 3. Individual setting file (example)

/etc/monit.d/test.conf

//Monitoring process settings
check process test matching "test"
//Startup settings
start program "/usr/local/test/bin/start_test.sh"
//Stop setting
stop program "/usr/local/test/bin/stop_test.sh"
//If there is no process, restart
if does not exist then restart
//Notify slack *
if does not exist then exec "/usr/local/test/bin/slacknotice.sh"
//If you do not wake up after restarting 5 times during 5 monitoring, stop
if 5 restarts within 5 cycles then unmonitor

Don't forget to give execute permission to the executing shell. $ chmod +x
Slack notification reference site: https://cloudpack.media/10085

It is recommended to include the following cron as a monit best practice.

echo "0 */1 * * * /usr/bin/monit monitor all" >> /var/spool/cron/root

https://hogem.hatenablog.com/entry/20090723/1248358467

4. Execution command

Start command $ systemctl start monit Automatically starts when the OS starts $ systemctl enable monit Stop command $ systemctl stop monit status $ monit status Reload when setting is changed (Important !!) $ monit reload Test command when changing settings $ monit -t Know the monitoring status $ monit summary When monit is skipped (when Not monitored) $ monit monitor all Command list $ monit -h

5. Management screen (Monit Service Manager)

IP: IP of monit server PORT: PORT set in ⑤' http://XXX.XXX.XXX.XXX:2812/

6. About paid M / Monit

The following sites were described in detail. https://inokara.hateblo.jp/category/monit

[LINUX] Automation of server monitoring etc. with Monit