If you are running a VPS, for a production server, it is very useful to have a process that monitors, and restarts if failed, and notifies you of key processes, like apache, mysql, postfix & ssh.
Monit is a free open source tool that does the job.
Took me a little while to get my head around the setup, but it is actually very simple, one you know, and can be done in 5 minutes.
These are the step I take on Debian (should be the same for Ubuntu)
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sudo apt-get install monit |
You don’t need to start anything or add it to any startup files, it does that automatically
There are a few settings needed to allow notification, and email address, an email server and a httpd server so you can monitor. These are in /etc/monit/monitrc
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sudo vim /etc/monit/monitrc |
Find the comment line with the word mail server. My mail-server is on MailGun and my server is on Google Cloud Compute so uses port 2525. (obviously change the myuser / mypasswd / mydomain )
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set mailserver smtp.mailgun.org port 2525 username "myuser@mydomain.com" password "mypasswd" |
Find the comment line # set alert sysadm@foo.bar and add the line
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set alert myuser@mydomain.com |
Find the comment # set httpd port 2812 and uncomment (remove the #) the first 3 lines so you get
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set httpd port 2812 and use address localhost # only accept connection from localhost allow localhost # allow localhost to connect to the server and |
Save the file & then do a quick configuration test
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sudo monit -t |
if OK reload monit
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sudo /etc/init.d/monit reload |
and check the log (as any issues with mail server will show now )
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sudo tail -f /var/log/monit.log |
ctril-c to stop following the log
check the status, the following command should show just one ‘System’
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sudo monit status |
Now we add the services we want to monitor, for me that is apache, mysql, ssh and postfix and these are all redefined in /etc/monit/monitrc.d so we just need to copy the definitions into /etc/monit/conf.d like so
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cd /etc/monit/monitrc.d sudo cp apache2 openssh-server mysql postfix ../conf.d |
restart monit
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sudo /etc/init.d/monit reload |
check the status , the following should give you all the info
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sudo monit status |more |
And that is it, now if say mysql dies, it will be restarted and you will get an email
