Below are the five most recent posts in my weblog. You can also see a chronological list of all posts, dating back to 2003.

Cobra mk. 3

Cobra mk. 3

Four years ago, whilst looking for something unrelated, I stumbled across Tom Morton's port of "Frontier: Elite II" for the Atari to i386/OpenGL. This took me right back to playing Frontier on my Amiga in the mid-nineties. I spent a bit of time replaying Frontier and its sequel, First Encounters, for which there exists an interesting family of community-written game engines based on a reverse-engineering of the original DOS release.

I made some scrappy notes about engines, patches etc. at the time, which are on my frontier page.

With the recent release of Elite: Dangerous, I thought I'd pick up where I left in 2010 and see if I could get the Thargoid ship. I'm nowhere near yet, but I've spent some time trying to maximize income during the game's initial Soholian Fever period. My record in a JJFFE-derived engine (and winning the Wiccan Ware race during the same period) is currently £727,800. Can you do better?

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A few weeks ago I went to see Blade Runner: The Final Cut in a one-off showing at the Tyneside Cinema. I've only watched the Final Cut once and that viewing was a bit compromised, so it was nice to see it properly, and on a massive screen with decent surround sound too.

Whilst watching it I saw something that I thought might potentially have been a visual reference to Scott's earlier movie, Alien. When Deckard is climbing onto the roof of the Bradbury building, there's a decorative motif that to me, looks very Giger-esque, biomechanical, a bit like a chest-burster.

click for full frame

click for full frame

I went back and took a screenshot from the Blu Ray at the same point. What do you think?

As it happens, whilst the inner regions of the building in the movie are the Bradbury building (or at least the entrance hall), I don't think the upper exterior shots are.


Purge

Purge

There are a few other, well-known references to Alien in Blade Runner, although they are likely simply re-used effects rather than explicitly easter eggs. The display screen in Gaff's Spinner is re-used from the Narcissus (here's a comparison) and the ambience in Deckard's apartment also featured in the Nostromo's medical bay. Some enterprising person has put together a 12 hour session of that particular sound effect looping. There's a number of other comparisons and spots at this propsummit.com thread.

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-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512,SHA1

I'm transitioning from my old, 1024-bit DSA PGP key, FD35 0B0A C6DD 5D91 DB7A 83D1 168B 4E71 7032 F238, to my newer, 4096-bit RSA key, E037 CB2A 1A00 61B9 4336 3C8B 0907 4096 06AA AAAA.

If you have signed my old key, I'd be very grateful if you would consider signing my new key. (Thanks in advance!)

This is long overdue! I've had 06AAAAAA since 2009, but it took me a while to get enough signatures on it for me to consider a transition. I still have far more signatures on my older key, owing to attending more conferences when I was using it than since I switched.

This statement, available in plaintext at http://jmtd.net/log/pgp_transition/statement.txt, has been signed with both keys.

I've marked my old key as expiring in around 72 days time, which coincides with my change of job, and will be just short of ten years since I generated it.

-----BEGIN PGP SIGNATURE-----
Version: GnuPG/MacGPG2 v2.0.22 (Darwin)
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=JBA4
-----END PGP SIGNATURE-----
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I'm changing jobs!

From February 2015, I will be joining Red Hat as a Senior Software Engineer. I'll be based in Newcastle and working with the Middleware team. I'm going to be working with virtualisation, containers and Docker in particular. I know a few of the folks in the Newcastle office already, thanks to their relationship with the School of Computing Science, and I'm very excited to work with them, as well as the wider company. It's also going to be great to be contributing to the free software community as part of my day job.

This October marked my tenth year working for Newcastle University. I've had a great time, learned a huge amount, and made some great friends. It's going to be sad to leave, especially the School of Computing Science where I've spent the last four years, but it's the right time to move on, It's an area that I've been personally interested in for a long time and I'm very excited to be trying something new.

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I've just recently built the large bulk of VMs that we use for first semester teaching. This year that was 112. We use the same general approach for these as our others: get a generic base image up and running, with just enough configuration complete so a puppet client starts up; get it talking to our master; let puppet take it from there.

There are pragmatic balances between how much we do in the kickstart versus how much we do in puppet, but also when we build a new VM from scratch versus when we clone an existing image, and how specialisation we do in the clone image.

Unfortunately this year we ended up in a situation where our clone image wouldn't talk to our puppet master out of the box, due to some changes we'd made to our master set up since the clone image was prepared. We didn't really have enough time to re-clone the entire set of VMs from a fixed base image, and instead needed to fix them whilst up. However we couldn't rely on puppet to do that, since they wouldn't talk to the puppet master.

We needed to manually reset the puppet client state per VM and then re-establish a trust relationship with the correct master (which is not the default master hostname in our environment anymore). Luckily, we deploy a local account with a known passphrase via the kickstart, which also has sudo access, as an interim measure before puppet strips it back out again and sets up proper LDAP and Kerberos authentication. So we can at least get into the boxes. However logging into 112 VMs by hand is not a particularly pleasant task.

In the past I might have tried to achieve this using something like clusterssh but this year I decided to give ansible a try instead.

Ansible started life, I believe, as a tool that would let you run arbitrary commands on remote hosts, including navigating ssh and sudo as required, without needing any agent software on the remote end. It has since seemed to grow into an enterprise product in its own right, seemingly in competition with puppet, chef, cfengine et al.

Looking at the Ansible website now I'd be rather put off by just how "enterprisey" it has become - much as I am by the puppet website, if I'm honest - but if you persevere past the webinars, testimonials, etc. etc., you can find yourself to the documentation, and running an arbitrary command is as simple as

  • defining a list of hosts
  • running an ansible command line referencing some or all of those hosts

The hosts file format is simple

[somehosts]
host1
host2
...
[otherhosts]
host3

The command line can be a little bit more complex, especially if you need to use one username for ssh, another for sudo, and you don't want to use ssh key auth:

ansible -i ./hostsfile somehosts -k -u someuser \
    --sudo -K -a 'puppet agent --onetime --no-daemonize --verbose’

"all" would work where I've used somehosts in the example above.

So there you go: using one configuration management system to bootstrap another. I'm sure I've reserved myself a special place in hell for this.

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Older posts are available on the all posts page.


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