Simplemonitor - Python-based monitoring

While searching for a simple monitoring für my root servers, I’m stumbled over a python-based software called Simplemonitor. Other alternatives, like Nagios, or forks like Incinga etc., were a bit too much for my needs.

What is SimpleMonitor?

SimpleMonitor is a Python script which monitors hosts and network connectivity. It is designed to be quick and easy to set up and lacks complex features that can make things like Nagios, OpenNMS and Zenoss overkill for a small business or home network. Remote monitor instances can send their results back to a central location.

My requirements were simple:

  • Ping monitoring
  • TCP monitoring
  • HTTP monitoring
  • Service monitoring
  • Disk space monitoring

Monitoring is nothing without alerting, so I was pretty happy that Simplemonitor is able to send messages into a Slack channel! But it can also send e-mails, SMS, or it can write into a log file. To get a full feature overview, visit the Simplemonitor website.

The project is hosted on GitHub. If you are familiar with Python, you can contribute to the project, or you can add features as you need.

Installation & configuration

The installation is pretty simple: Just fetch the ZIP or the tarball from the project website, and extract it.

The configuration is split into two files:

  • monitor.ini
  • monitors.ini

The naming is a bit confusing. The monitor.ini contains the basic monitoring configuration, like the interval for the checks, the alerting and reporting settings. The monitors.ini contains the configuration of the service checks. That’s confusing, that confused me, and so I changed the name of the monitors.ini to services.ini.

[monitor]
interval=60
monitors=services.ini

The services.ini (monitors.ini) contains the service checks. This is a short example of a ping, a service check, a port check, and a disk space check.

[ping-host1]
type=host
host=host1.tld.de
tolerance=3

[svc-postfix-host1]
type=rc
runon=host1.tld.de
service=postfix

[port-postfix-host1]
type=tcp
host=host1.tld.de
port=25

[diskspace]
type=diskspace
partition=/
limit=4096M

The alerting is configured in the monitor.ini. I’m using only the Slack notification. All you need is a web hook and the corresponding web hook URL.

[slack]
type=slack
channel=#monitoring
limit=1
url=https://hooks.slack.com/services/afjnsdifnsdfnsdf

In case of a service fail, or service recovery, a notification is sent to the configured Slack channel.

To start Simplemonitor, just start the monitor.py. It expects the monitor.ini in the same directory.

root@host1 /opt/simplemonitor # python2 monitor.py -v
SimpleMonitor v1.7
--> Loading main config from monitor.ini
--> Loading monitor config from services.ini
Adding host monitor ping-host2
Adding rc monitor svc-postfix-host1
Adding rc monitor svc-nginx-host1
Adding rc monitor svc-mysql-host1
Adding rc monitor svc-fail2ban-host1
Adding rc monitor svc-postgrey-host1
Adding rc monitor svc-phpfpm-host1
Adding rc monitor svc-named-host1
Adding diskspace monitor diskspace
--> Loaded 9 monitors.

Adding logfile logger logfile
Adding slack alerter slack

--> Starting... (loop runs every 60s) Hit ^C to stop
php_fpm is running as pid 33937.
Passed: svc-phpfpm-host1
named is running as pid 566.
Passed: svc-named-host1
fail2ban is running as pid 41306.
Passed: svc-fail2ban-host1
Passed: diskspace
postgrey is running as pid 649.
Passed: svc-postgrey-host1
mysql is running as pid 23726.
Passed: svc-mysql-host1
Passed: ping-host2
postfix is running as pid 53332.
Passed: svc-postfix-host1
nginx is running as pid 52736.
Passed: svc-nginx-host1

Summary

I really like the simplicity of Simplemonitor. Download, extract, configure, run, done. That’s what I’ve searched for. It is still under development, but you should not expect that it will gain much complexity. Even if features will be added, it should be a simple monitoring.