Monitoring Servers with Webmin

This is an interesting feature in Webmin that provides a way to monitor daemons on the server and notify administrators of down services. Webmin attempts to implement many of the standard functions of the more full featured Nagios. You can create custom notifications and get notified via email, SMS or a pager.

Proceed to Others/System and Server Status and you will see a list of the daemons on the system. Of course the more you have installed the more options you will see listed. Each daemon is listed and then the location, (local or on another server) as well as the status of the daemon.

The status may be on (green check), off (red x) or not installed (red arrow).

Service monitoring can be turned on when you select “Scheduled Monitoring”. Enable the scheduled monitoring and then select how often to check the service. The default is 5 minute intervals. Also select/modify the time periods and days for monitoring.

Select the email option for notification and then enter an email to receive the alerts. You can also set up SMS notifications and pagers. Once you have it set up be sure to manually turn off a service to test the response.

Here is the default message that I sent when a failure occurs.

Monitor on webmin for 'Extended Internet Server' has detected that the service has gone down at 05/Nov/2012 23:05

Edit the message using macros to create a message that you want. In the System and Service Status select “Email Templates” at the bottom of the page to create your own template. Here are the options available.

${DESC} Service description

${HOST} Host being monitored

${DATE} Current date

${TIME} Current time

${STATUS} Service status, such as Down

In addition, you can use conditional blocks like : ${IF-DOWN} Service is down ${ELSE-DOWN} Service is OK ${ENDIF-DOWN}

Add a Monitor

There are many monitoring types that can also be added. Select a monitoring option, in this example disk space and then click “Add monitor type:”.

Now you will options for setting up the partition that you want to monitor as well as the notification options. Set to check on schedule and then enter the message template that you have created or use the defualt.

You can create commands that can be issued when the disk reaches the size limits you set. Select the partition and how to measure the the free space. Note it is not filled space that you are measuring.

Save and now the system will be monitoring the partition you selected.

No doubt a dedicated program like Nagios is more capable to monitor your network infrastructure, but at least this feature in Webmin provides a way to get some basic checks on the servers that you are working with.