Category Archives: Virtual Machines

Migrating a DNS server to PowerDNS

Today I had to migrate a customer’s DNS server to a new server… This because the old server (a very old plesk instance) was end of life.

As I have very good experiences with PowerDNS, we decided to migrate from Bind (Named) to PowerDNS.

PowerDNS provides you with the utilities to do so, but I did not find a straight forward way to export/import zones from Bind into PowerDNS.

Installation of PowerDNS and PowerAdmin (a PowerDNS Gui) is out of the scope of this document, so I assume you already have a working PowerDNS server.

These are the steps I had to perform to migrate from the Plesk 8.2 server to PowerDNS:

1) First of all, you need to allow zone transfer (AXFR) on your bind server from your new PowerDNS server IP. You need to change the contents of /etc/named.conf in something like this (add the allow-transfer lines in the Options block.

2) Reload or restart named to take effect:

3)Test a zone transfer, eg:

4) Now that you know zone transfer is working, create a list of domains that your Bind server is ‘serving’.  In my case i have to remove some extra .lock and .saved_by_psa files from my listing. If you use this tutorial, your command can look differently of course.

If needed: check if the domains in bind still use your old nameservers… (do not polute your new powerDNS server :))

Then delete all domains from /root/domainlist.dns if they not valid anymore
5) Import your zones by:
a) Create Zone Import SQL scripts

From these generated files, remove duplicate SOA records from all import files:

If needed: change TTLs:

Depending if your imported zones need to be set as NATIVE or MASTER

Change extra stuff with sed, like hostmaster and so on

b) Test import into mysql

c) Verify in poweradmin and drop the imported zone (or you’ll get an import error on the next step, which is not bad or something… but hey :))

d) Import all your zones, if you like what you have done:

 

Kernel update errors on a Debian Squeeze Xen Virtual Machine

When performing a apt-get upgrade on a Xen Debian Squeeze Virtual Machine, you might encounted errors like:

 

This happens because grub cannot find the virtual disk in order to rewrite the server’s initrd image.

Since Xen kernel management is transparent to your machine itself, you can safely remove grub by:

This is the output of the remove command: