mtx33q / openshift-origin-cartridge-monit

OpenShift Monit downloadable cartrige

OpenShift monit cartridge

This GIT repository contains a downloadable monit cartridge than OpenShift users can use to monitor various metrics in their applications, like memory usage, quota usage, etc.

Users can configure alert email to receive notifications. To do so, you need to set MONIT_ALERT_EMAIL before installing the cartridge:

rhc env set [email protected] -a YOUR_APP

After this, you can add this cartridge to your application:

rhc cartridge-add http://goo.gl/jiIB2C -a YOUR_APP

What you get for free :-)

OpenShift memory quota

If you are using OpenShift Online with 'Free' account, then your gears are limited to 512MB of memory. In case your application grow beyond this amount, OpenShift will kill it and then try to restart it. However, you will not receive any email that this happened. This cartridge will send you email when your application is using 80% of the gear memory and automatically restart your application when it is using 90% of gear mem.

OpenShift storage quota

All gears have fixed storage quota set on OpenShift. In case your application grows (apache logs, etc), this cartridge will send you email if you are at 80% of gear capacity. If your application goes more than 90% of the gear capacity, this cartridge will run tidy operation, which will clean up all logs in order to free some storage.

OpenShift application availability

The default monit configure provide periodical check of availability of your application. If you app goes down for whatever reason, an alert is send to your email and if your app is down for longer than 1.5 minute, monit will try to restart the primary cartridge to fix it.

Custom rules

The .monitrc file is available to you in your gear home directory. To add more rules or change the default rules, you need to do rhc ssh into your application and edit .monitrc file. You can find more complex examples of monit rules on monit site.

Monit Service Manager

Monit comes with a simple web-interface where you can see the status of things that are monitored. You can access this web interface by visiting the /monit-status URI in your application. You will be prompted for a password, which is printed out to console when you finish installing this cartridge. If you loose this password, you need to ssh into the gear and execute:

env | grep -r MONIT_PASSWORD

Note about scripts

As you can see in default monitrc, you can't simply execute the 'control start', but you need to wrap this script by oo-env.sh wrapper. This is due to limitation of Monit itself, described here: http://mmonit.com/wiki/Monit/FAQ#execution