About Peter Thurner

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So far has created 22 blog entries.

Howto use the hetzner backup space with rsync

This post describes how to overcome the hetzner backup space restriction of not being able to set linux uid / gids and so on on the (sshfs) mounted backup space. It does not describe how to do incremental backups using rsync and hardlinks.

1. The problem
The www.hetzner.de backup space does not allow for rsync to change […]

By |November 26th, 2014|Admins knowledge, Hosting, www.hetzner.de|Comments Off on Howto use the hetzner backup space with rsync

Website unter heavy load from IP.unknown.SteepHost.Net

I recently had a customer who experienced high network throughput on one of his machines. He noticed by receiving multiple traffic warnings from the hetzner monitoring system, which monitors in and outgoing network traffic and sends emails when a total defined limit is exceeded. If you are with hetzner.de, I highly recommend using this.

A great […]

By |September 16th, 2014|Admins knowledge, Networking, Uncategorized, Webserver|Comments Off on Website unter heavy load from IP.unknown.SteepHost.Net

Using a reverse SSH Tunnel to access Machines behind a NAT or Firewall

When the machine that needs to be accessed by SSH is located behind a NAT router or a firewall that allows only connections that have been established by the internal machine, an SSH Tunnel is a simple way to accomplish that. It creates an outbound connection to a public server, through which SSH access can […]

By |September 9th, 2014|Admins knowledge, Uncategorized|Comments Off on Using a reverse SSH Tunnel to access Machines behind a NAT or Firewall

Renaming a virtual machine domain with virsh

There is no API to accomplish renaming a domain using virsh. The well known graphical tool `virt-manager` therefore also does not offer the possibility to rename a libvirt domain. In order to do that, you have to stop the virtual machine and edit the .xml data like follows:
root@host ~ # virsh dumpxml machine.example.com > machine.xml
root@host […]

By |September 8th, 2014|Admins knowledge|Comments Off on Renaming a virtual machine domain with virsh

Remove old Kernels from full /boot partition

When the /boot partition is full, it might not be possible anymore to remove old kernel versions by just using apt. A full /boot partition can lead to problems during boot as well. In this case, the following error might be shown during apt operations that trigger an `update-initramfs`:
gzip: stdout: No space left on device
E: […]

By |September 8th, 2014|Admins knowledge, Uncategorized|Comments Off on Remove old Kernels from full /boot partition

Disable or configure notify-osd onscreen popup notification window on ubuntu

I am currently running ubuntu 14.04 on my workstation(s). One thing that I don’t like is thunderbird displaying popup notification windows, which in combination with i3wm, overlay windows on other workspaces and can’t be clicked away, therefore basically denying usage of that particular part of the window.

Disabling notify-osd – the fast way

The onscreen popup notifications […]

By |May 31st, 2014|Window manager|Comments Off on Disable or configure notify-osd onscreen popup notification window on ubuntu

Howto migrate a single disk Linux installation to mdadm raid with luks encryption and LVM volumes with minimum downtime in 11 Steps

This document describes howto migrate a single disk linux installation used for virtualization with kvm to a RAID 5 array. In this setup, 2 disks are added. Including the original disk a 3 disk RAID 5 is created. It is sought out to do the complete migration causing only one reboot downtime. During the process of syncing the virtual machine data, the guests can experience losses in disk performance.

Overview: Current and target partitioning layout
This manual is using mdadm to create software RAID. It can be adapted to any RAID level that can support one disk missing. The setup used as in this example is a CentOS 6.5 installation, partitioned as following described: […]

By |May 16th, 2014|Linux distributions|Comments Off on Howto migrate a single disk Linux installation to mdadm raid with luks encryption and LVM volumes with minimum downtime in 11 Steps

Installing and managing .rpm packages on CentOS 6.5

It is possible to organise .rpm package files, for example downloaded by hand (or wget), in a way that lets you use them as a repository for the yum tool. This way you can have your own local yum repository of .rpm files.
# mkdir local-repo
# mv gdisk-0.8.7-125.1.i686.rpm local-repo/
# yum install createrepo
# […]

By |May 5th, 2014|Linux distributions|Comments Off on Installing and managing .rpm packages on CentOS 6.5

Disguise IP addresses in apache (and other) log files

If you want to disguise IP addresses in logfiles, there is a fast and simple way to do so with sed. If there is no option to disable logging the full IP address in the application, you could use a cronjob to run this every now and then. It will remove the last decimal of […]

By |October 30th, 2013|Webserver|Comments Off on Disguise IP addresses in apache (and other) log files

Using german umlauts (ä,ö,ü,ß,€) on US layout keyboards

Creating a ~/.Xmodmap file
In order to map key combinations to specific special characters you have to create a .Xmodmap file within your users home directory. First we have to find out what the keycodes of the keys you want to map are. For this enter “xev” and press the appropriate key. You will get an output like this: […]

By |October 29th, 2013|Window manager|Comments Off on Using german umlauts (ä,ö,ü,ß,€) on US layout keyboards