Best Practices / Tech Tips &Tricks’ Blogs

Changing the VLAN-ID of an interface in a bridge with minimal downtime

datacenter August 23rd, 2013

Our upstream-provider needed to change the VLAN-ID of our uplink to be in line with their policies. We wanted to do this with minimal downtime. Check out the script we ran on the gateway machines, the VLAN-IDs were changed almost instantly, total unavailability was less than a second.

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Debian and Trac: How to solve the ‘No module named svn’ Trac error.

coding June 11th, 2013

How to solve the ‘No module named svn’ Trac error.

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Checking for rogue Apache modules

magnifying_glass April 3rd, 2013

An Icinga check to detect rogue Apache modules.

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Booting a compressed FreeBSD system using TFTP inside KVM

freebsd January 4th, 2012

Over the years, we have performed some experiments at Kumina to run the FreeBSD operating system inside KVM. The main problem with FreeBSD was the lack of proper virtio drivers. As of recently FreeBSD gained support for virtio, renewing our interest in testing FreeBSD.

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Fixing hanging Crypto Stick (and other USB peripherals) problems

nitrokey December 28th, 2011

We had problems with our Crypto Stick ‘hanging’ randomly. An experimental patch from libusb fixes this. We have released packages with this fix.

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Spoofing MAC addresses using fakemac

code December 14th, 2011

One of our customers uses a piece of software that depends on the MAC address of the running system. Unfortunately this application misbehaves when used on Amazon EC2 cloud computing. Therefore we have written a small piece of software called fakemac.

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Debugging puppet queueing

puppet December 9th, 2011

Today we ran into a problem where the data put in ActiveMQ by the puppetmaster seemed corrupted in some way. When running the puppet queue daemon on the foreground (with –debug –verbose –no-daemonize), we noticed messages like these: info: Loaded queued catalog in 22.16 seconds debug: Searched for resources in 0.31 seconds err: Could not […]

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Check SSL certificates

ssl_checks August 24th, 2011

This post is mostly a collection of commands that can help in juggling around SSL certificates and associated files. Check SSL certificates and make sure they are what you think they are. Especially when things do not go as expected, these commands are handy to have around.

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