BenV's notes

Another day, another Check_MK plugin!
This one is inspired by smokeping, but different because it doesn’t need smokeping. It does need the tool formerly known as Matt’s TraceRoute, aka mtr. It’s installed on all my machines by default and easily available in all distro’s that are worthy. Even pokemon OS has it 😉

The reason I wanted to build this plugin was first of all because of pretty graphs (of course!). The second reason was that my girlfriend had some network issues to figure out, but only ping and DNS resolve times don’t paint a complete picture. This plugin makes some graphs that hopefully fill that void a bit 🙂

Now that you’ve skipped the last 2 paragraphs, here are some example graphs that I made while testing the plugin:

This is the plugin status per host on the service overview page of Check_MK. As you can see I configured multiple hosts. (continue reading…)

One of the cool things Check_MK offers these days is the option for custom notifications. Email notifications are of course fine, but a lot of people are also interested in Pagerduty or their own SMS service or whatnot. Personally I was interested in an IRC based notification system where alerts would simply be sent as a message into a specific channel on my IRC server.
Let’s see how we can implement that 🙂
(continue reading…)

Here’s another small plugin for Check_MK – this one keeps track of Nullmailer queues.

Without further delay, here’s the package:
[Download not found]
[Download not found]

For installation check out one of my older plugin posts 😉
Have fun with this new plugin! 🙂

ChangeLog:
V1.1: Updated agent to check different queue location for Debian etc. No other changes.
V1.0: Initial version

A while ago when faced ‘why is my disk slow’ I realized “hej, I have an SSD… let’s use it as cache!”.
Easier said than done, because these days you have tons of options. A quick glance at them shows BCache, DM-Cache, FaceBook’s Flash-Cache or what I went for which is based on Flash-Cache: EnhanceIO. There’s probably more of them, while writing this I ran into this article on LVM cache – sounds interesting too.
Here’s a little comparison between a few of the above options: different ssd to hdd cacheing options on askubuntu.com. (continue reading…)

This one has been on my todo list for a while, so today I took a stab at it: a fail2ban plugin for Check_MK.
My previous plugin (LMSensors plugin for Check_MK) still gets quite a few hits, so I figured you guys might like this one as well.

Why? Pretty graphs of course 😉
Another reason might be that you want to keep an eye on how many ssh bots etc fail2ban keeps out. (continue reading…)