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…)

With the v1.3 patch coming soon ™, hopefully today, it’s time to play Terraria again! 🙂
One of the claims is that it will now be easier / at all possible to run multiplayer games through steam. Well, we’ll see about that, but I figured this would be a great time to get my own dedicated headless server up and running. (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

Surprise, surprise, something broke with the readline library upgrade 😉
While upgrading my slackware(64)-current installation today, this happened:

Verifying package readline-6.3-x86_64-1.txz.
Installing package readline-6.3-x86_64-1.txz:
PACKAGE DESCRIPTION:
# readline (line input library with editing features)
#
# The GNU Readline library provides a set of functions for use by
# applications that allow users to edit command lines as they are typed
# in. Both Emacs and vi editing modes are available. The Readline
# library includes additional functions to maintain a list of previously
# entered command lines, to recall and perhaps edit those lines, and
# perform csh-like history expansion on previous commands.
#
Executing install script for readline-6.3-x86_64-1.txz.
Package readline-6.3-x86_64-1.txz installed.

Package readline-5.2-x86_64-4 upgraded with new package ./readline-6.3-x86_64-1.txz.

awk: error while loading shared libraries: libreadline.so.5: cannot open shared object file: No such file or directory

Package: btrfs-progs-20150213-x86_64-1.txz
‘/mnt/general_stores/OS/Slackware/slackware64-current/./slackware64/a/btrfs-progs-20150213-x86_64-1.txz’ -> ‘/var/cache/packages/./slackware64/a/btrfs-progs-20150213-x86_64-1.txz’
‘/mnt/general_stores/OS/Slackware/slackware64-current/./slackware64/a/btrfs-progs-20150213-x86_64-1.txz.asc’ -> ‘/var/cache/packages/./slackware64/a/btrfs-progs-20150213-x86_64-1.txz.asc’
awk: error while loading shared libraries: libreadline.so.5: cannot open shared object file: No such file or directory
ERROR - Package not installed! gpg error!
awk: error while loading shared libraries: libreadline.so.5: cannot open shared object file: No such file or directory

Hmz, seems like awk (which is actually gawk) hasn’t been updated yet, yet it still links to the old libreadline (5).
This in turn breaks loads of things, so while packages are still being rebuilt / link to the old libreadline this might be a good idea for now:

# This is for slackware64, drop the 64 if you run an ancient machine / install.
root@slack64:~# ln -sf /usr/lib64/libreadline.so /usr/lib64/libreadline.so.5
root@slack64:~# ln -sf /usr/lib64/libhistory.so /usr/lib64/libhistory.so.5

Fixed for now 🙂

If you’ve ever had the burden of being an admin of an office with imbeciles that use AccountView you probably already lost a bunch of hairs over it, if it didn’t push you to angry KILL CRUSH DESTROY mode (yet). Fortunately my encounters with the product are usually only in the form of “kill -9 hanging task AVWIN.EXE” or “recover from last night’s backup“. (when will those idiots start using a real database as backend instead of those easily corrupted DBF/CDX files…. idiots. Then again, the horrible garbage still uses FoxPro, so color me surprised.)
Today my boss forwarded me an email with the corresponding ‘Here, update instructions, go fix!‘ command. After a few sighs, a download and a backup of the current installation (version 9.2) I went to work.
Start the installer, next a few times, point it to the old … wait, why can’t I select the network folder that we have the old one installed on?
Apparently since version 9.3 you can’t select non local folders anymore, no matter if you select the server/standalone/workstation install.
Giving it a mapped folder location like “Y:\AccountView9” resulted in a no such location or permission denied message.
Great.
Just great.
But then I got this idea: What if I give it a symlink on a local folder?

C:\Users\Administrator> mklink /D "C:\AccountView9" "\\192.168.1.2\AccountView\AccountView9"
symbolic link created for "C:\AccountView9" <<==>> "\\192.168.1.2\AccountView\AccountView9"

Next I went through the 9.4a installer again and pointed it to the C:\AccountView9 symlink. Result?
“SURE THING! Did you know that there’s an old installation in that folder?”
Ha. I WIN 😉

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…)