Posts Tagged ‘zenoss’

No one likes to forget to renew a domain. Its not wholly uncommon though. Microsoft forgot to renew passport.com in 1999, and hotmail.co.uk in 2003. Vivendi Universal forgot to renew its MP3.com in 2003, the Washington Post forgot to renew in 2004, and Foursquare forgot to renew their domain in 2010.

I stumbled on the check_domain nagios plugin this weekend so I figured I would make some quick modifications and roll it into a Zenpack. You can find ZenPacks.community.CheckDomain on my github page. It has a really boreing doomsday graph included. Hope someone finds it useful.

Nginx is a great little web server. I have posted previously about using it as a reverse proxy. Weather your using it as a reverse proxy or as a normal webserver you will probably eventually want to know what its doing over time so you can adjust resources as necessary.

The other day I threw together a Zenpack to make it easier to setup monitoring on new Zenoss instances. It contains a command data source “check_nginx_ng” which is a slightly modified version of Chris Kellys check_nginx_ng which in turn was based on check_nginx by Mike Adolphs. So thanks to them for doing the majority of the work! If your interested you can pick it up over on github. ZenPacks.community.NginxStatus

Redundant power is a necessity for any highly available system. Most servers have redundant power supplies and the common design pattern is to have each power supply plugged into a power distribution units that are on separate circuits. One challenge with this type of dealing with this type of design is monitoring the power load.

Monitoring A/B power is not as easy as monitoring the individual PDUs. Some servers will draw power from both power supplies, other will draw from one or the other. That being the case the circuits are almost never all or nothing, and they are almost never perfectly balanced. In order to effectively monitor the whole picture you need to monitor the aggregate power consumption of both circuits.

I’ve not really seen direct support in any Network Monitoring System that I have ever looked at. Zenoss is the NMS I have been using recently and while it has many rules for alerting it does not support alerts based on multiple data points. To solve my issue I ended up writing a small script that would query the SNMP OID for the total power load on a single PDU for two specified hosts and return the aggregate as well as the individual PDU loads in Nagios plugin format. That gave me a single data point that I could use for thresholds and alerts.

I have created a ZenPack that includes the script as well as the templates for graphing and thresholds. The thresholds and graphs are specific to a 20A circuit but could easily be modified for others.

The aggregateAPCpduAB ZenPack can be found on my github profile.

http://github.com/nickanderson/ZenPacks.community.aggregateAPCpduAB

Recently I was building a ZenPack for Zenoss. The ZenPack included an Event Command which executed a custom script. I wanted to store the custom script in the ZenPack and I didn’t want to do anything other than have proper script dependencies in place for it to work.

${here/ZenPackManager/packs/ZenPacks.community.YOURZENPACK/path}/libexec/yourscript.sh  ${dev/manageIp}

Custom scripts can be placed in $ZENHOME/ZenPacks/ZenPacks.CompanyName.Package/Zenpacks/CompanyName/Package/lib but if you want them to be executable place them in libexec.

Thanks to Matt Ray for telling me how to properly path the Event Command and the note about scripts in libexec getting the executable bit set, the docs I found only specified the lib directory.

I know I’ve mentioned how much I love the sysstat package before. I use sar regularly to help with performance diagnostics (Analyzing Linux System Performance And Finding Bottle Necks, CPU Performance Analysis In Linux, Baseline Analysis Is Important, CPU Performance Analysis In Linux Revisited). I wrote this little Nagios plugin to collect the performance metrics that sar collects.

I use this plugin with Zenoss and I set any performance thresholds there, more important to me was collecting the information for historical graphing. I searched around and didn’t really find any existing solutions thats why anyone wanting to do similar perhaps with cacti is stuck with my craptastic code (or please point me to a better implementation).  Anyway if you want to grab the plugin and check it out its on github.

check_sar_perf