Automatically install and configure Monit on your Debian 10/11 and Ubuntu 20.04 server

Note, 23-09-2022: this script has been tested by me but it might very well be that in the upcoming days I will make some minor improvements. What might be changed is the monitor interval (currently 30, configured in /etc/monit/monitrc) and some services could be added if any are suggested.

After building a function for the ISPConfig autoinstaller that adds support for automatically installing and configuring Monit, I figured that it might come in handy on existing servers where you can't re-run the autoinstaller. So I made some changes and got it working well on any Debian 10/11 and Ubuntu 20.04 server.

If any of the supported services are installed, it will add a monitor config for them. The scripts also sets up the web UI and you can let it configure a email address to send alerts to.

Currently supported services (please PM if you think I should add one!):

• sshd
• mariadb
• pure-ftpd-mysql
• apache2
• nginx
• named
• postfix
• dovecot
• rspamd
• php-fpm for PHP versions 5.6 - 8.1.

All you have to do to get a working Monit instance set up within seconds is to download the script and run it.
To set it up without a recipient for email alerts, run:

Code:

curl https://git.ispconfig.org/ispconfig/tools/-/raw/master/setup_monit.php -sL | php

To set it up with a recipient for email alerts, run:

Code:

curl https://git.ispconfig.org/ispconfig/tools/-/raw/master/setup_monit.php -sL | php -- [email protected]

Make sure to change the email address "[email protected]" to the email address that shall receive the alerts.

You can configure a SMTP server to send through in /etc/monit/conf-available/alerts - by default it uses localhost.

SSL for the Monit UI can be configured in /etc/monit/conf-available/webui - it might be necessary to change the path of the .pem file, and probably the file permissions for that file as well. Untested.

Monit documentation:
https://mmonit.com/monit/documentation/monit.html
https://mmonit.com/wiki/Monit/ConfigurationExamples

Feedback is welcome as always. Feel free to send me a PM.

 

Setting up SSL for the web UI when using Let's Encrypt with the acme.sh client:
Please note: if you already set up something like this for the ISPConfig panel, your mail services, or FTP services, this guide might be incompatible and following it is at own risk.
- Create a website for the hostname of the server, e.g. "server1.example.com".
- Disable auto subdomain
- Enable Let's Encrypt for the site.

Make sure the certificate for your hostname is created. I will use server1.example.com.
You can check if it exists with

Code:

ls -la /root/.acme.sh/server1.example.com

The certificate files should be there.

To use this certificate for the Monit UI, run:

Code:

cd /var/www/server1.example.com/ssl/
cat server1.example.com-le.{key,crt} > server1.example.com-le.pem
chmod 600 server1.example.com-le.pem

Then open the webui config file with your favorite editor:

Code:

nano /etc/monit/conf-available/webui

Change the path to the .pem file and uncomment the 2 SSL lines:

Code:

set httpd port 2812 and
        SSL ENABLE
        PEMFILE /var/www/server1.example.com/ssl/server1.example.com-le.pem
        allow admin:MyPassword1

Restart Monit to apply changes:

Code:

systemctl restart monit

You can set up a script to regenerate the .PEM file automatically when the certificate has been renewed:

Open a new script file:

Code:

nano /etc/init.d/le_server1_pem.sh

Paste this in that file:

Code:

#!/bin/sh
### BEGIN INIT INFO
# Provides: LE .PEM AUTO UPDATER FOR MONIT
# Required-Start: $local_fs $network
# Required-Stop: $local_fs
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: LE .PEM AUTO UPDATER FOR MONIT
### END INIT INFO
cd /var/www/server1.example.com/ssl/
cat server1.example.com-le.{key,crt} > server1.example.com-le.pem
chmod 600 server1.example.com-le.pem
systemctl restart monit

Make the script executable:

Code:

chmod +x /etc/init.d/le_server1_pem.sh

To automatically trigger this script on renewal, we are going to use systemd.

Create and open the new systemd service:

Code:

nano /etc/systemd/system/le_server1_pem.service

Paste this in that file:

Code:

[Unit]
Description="Create new .pem file on certificate renewal"

[Service]
ExecStart=/etc/init.d/le_server1_pem.sh

Save and close this file. Then create and open the new systemd path file:

Code:

nano /etc/systemd/system/le_server1_pem.path

Paste this in that file and replace server1.example.com with the hostname you used:

Code:

[Unit]
Description="Monitor the hostname certificate files to trigger a recreation of the .pem file after renewal"

[Path]
PathModified=/root/.acme.sh/server1.example.com/
Unit=le_server1_pem.service

[Install]
WantedBy=multi-user.target

Save and close this file. Then start the service and enable it so it runs on startup:

Code:

systemctl start le_server1_pem.path

And enable it so it runs on startup:

Code:

systemctl enable le_server1_pem.path

And we're done!

Of course, replace server1.example.com in this guide with your hostname.