Raspberry Pi, and Raspberry Pie


I went to bed early last night cos I knew I had to be up early this morning. Getting up at 05:30 is something that is incredibly rare for me. Unfortunately, it was a bit pointless this time around.

I was trying to get one of these:

Copyright 2011-2012, Raspberry Pi Foundation

It’s called a Raspberry Pi, and it’s essentially a computer the size of a credit card. With an ARM11 processor manufactured by Broadcom, 256M RAM, HDMI/RCA video output, 2 USB ports and Ethernet, powered by micro-USB, with SD for storage. What more could you want for a basic computer system?

Initially, it’ll run a variant of either Debian or Fedora Linux, and my plan is to use it either as a local web server/proxy server/dns server, or maybe running XBMC as a low-power media frontend. It’ll also be good for simply messing about with.

Oh, did I mention the price of this thing? No?

$35 (USD).

In the process of trying to order one, we (everyone who wanted one) brought down not only RS Components’ website, but Premier Farnell too in mere seconds. They were warned about the traffic, but seemingly thought the warning a bit frivolous since both of them didn’t adequately prepare for a HUGE traffic surge.

And now I have a craving for raspberry pie.



YAY! *jumps around the room*

*realises it’s 02:46 AM*

*jumps around the room*

IPv6 just got properly enabled in the London and Atlanta data centres for linode.

EDIT: Now enabled on all the machines in my cluster :D

Updates / upgrades / lots of downtime

Hi folks

I’m planning a series of upgrades which WILL impact services running.

blastoise (affects all)

  • OS upgrade
  • Disk space upgrade – Done!
  • General security fixes and package upgrades – Done!

metapod (affects all)

  • OS upgrade
  • Disk space upgrade – Done!
  • General security fixes and package upgrades – Done!


  • phpBB version upgrade – Done!


  • WordPress version upgrade – Done!


  • WordPress version upgrade – Done!


  • MediaWiki upgrade
  • MantisBT upgrade

I haven’t a clue how long that’s all gonna take, but I’m planning to start this afternoon with some stuff, maybe do the OS updates just after tea, hopefully to get most of it done before going to bed.

I ought to do this kind of thing more often so it doesn’t get to this amount of work to do.

Technology updates

Quite a bit has happened recently!

I’ll try and give a bit of info about each, there’s quite a lot to write about though!


An IRC bot which stalks changes to Wikipedia based on regex matches. Read more

caterpie beedrill as minecraft server

Those of you who use my Minecraft server will know that the server known as “caterpie” was bad. Any more than one person connected, and it would lag to the depths of hell. I’ve replaced it with a 1.7G beast of a server, still running as an Amazon server instance.


I registered a new domain! I’m still in the process of setting the thing up though, but that will become my main website, not quite sure what I’m gonna put there yet, but it’ll probably replace what webspace I had at http://helpmebot.org.uk/~stwalkerster/


A couple of weeks ago, the IRC bot that we use over at Wikipedia’s Account Creation Assistance project decided it would stop giving notifications to the IRC channel.

I’ll write more about this at a later time, hopefully soon, but probably when I’ve finished messing with my new site :P

strobe light

Growing tired of the poor strobe light applications available on Android Market, I decided to build my own.

I’ll also write more about this too at a later time – I think this bit and the last one need their own posts.

Adding yourself to a linux user group without restarting your session

I recently ran into an issue where I wanted to add myself to a new group (hmbprototype) on my server cluster, but really didn’t want to kill all my processes and restart my session to apply the new group settings.

A bit of searching around lead me to this:

$ newgrp hmbprototype

Seems to have added that group to my list of groups for my current session! :D Obviously, you actually need to create the group and add yourself to it before using newgrp. :P

Before using this yourself, I recommend you look at the man page first ofc :)

$ man newgrp

Exim, IPv6, and lots of email errors

Since I eventually moved the email server (exim) over to the server blastoise, it’s been giving me grief. Something along the lines of rejecting emails because it wasn’t allowed to relay mail through itself, even though I’d actually told that it was allowed to:

hostlist   relay_from_hosts = <; localhost ;

However, blastoise is IPv6 capable, and prefers that over IPv4, and because all the settings point to "mail.helpmebot.org.uk" which points to both and 2001:470:1f09:1213::2, it was skipping "localhost", and preferring IPv6, which wasn't listed, hence the nice error log was filling up with messages like this:

220 helpmebot.org.uk ESMTP Exim 4.71 Sat, 19 Feb 2011 17:50:24 +0000
EHLO blastoise.helpmebot.org.uk
250-helpmebot.org.uk Hello blastoise.helpmebot.org.uk [2001:470:1f09:1213::2]
250 OK
550 relay not permitted

Hopefully the problem is fixed now, with the correct configuration (adding the brand new metapod's IPv4 and IPv6 addresses):

hostlist   relay_from_hosts = <; localhost ; ; ; 2001:470:1f09:1213::2 ; 2001:470:1f09:1581::2

In case you were wondering, the default separator for lists in Exim's config file is :, which causes "issues" with IPv6 addresses. A quick google told me to prepend <; to the beginning of the list, which changes the separator from : to ;, which doesn't cause a problem with IPv6 addresses. :)

Sometimes I really don't like it when that sort of thing happens... configuration stuck in a dark dusty corner somewhere breaks because something random changes like adding an IP to the system.


So, as you may or may not be aware, the entire address space of IP (version 4) addresses has now been allocated. This means it is likely a matter of months before the first ISPs around the world start running out of IP addresses to allocate to customers.

The solution to this is IPv6 (the sixth version of IP), which introduces a whole new address space which is much larger (340,282,366,920,938,463,463,374,607,431,768,211,456 (2^128) addresses) than the address space that IPv4 had (4,294,967,296 (2^32) addresses). However, although IPv6 is over 12 years old now, uptake has been very slow.

I’ve been rolling out IPv6 over this server for the past couple of hours, and after a few initial hiccups, I’m pleased to say it’s all working fine on IPv6, with 2 notable exceptions:

  1. MediaWiki doesn’t like IPv6 at the moment
  2. studentotakusociety.dyndns.org can’t be upgraded to IPv6 due to the nature of the domain name

Both of these are fixable in some way, the first is waiting on an upstream fix ( https://bugzilla.wikimedia.org/show_bug.cgi?id=27353 ), the second is waiting on the admins of that site actually buying a domain name like they’ve been promising.

This means that every site EXCEPT helpmebot.org.uk has bee updated to IPv6 without a problem – the irony is that helpmebot.org.uk was the one I wanted to do first, and had the most expectation to actually work.

The server itself is using a Hurricane Electric IPv6 tunnel, I’m using a gogo6 tunnel at home. It’s nice to be able to browse to places like http://www.v6.facebook.com/, in the knowledge that not many people either know about it, or would be able to get to that site without IPv6.

The bug with MediaWiki was caused by a regression, and has now been fixed. That’s only one site left to switch to IPv6 now :)