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OpenStack Paris workshop: Automated Deployment of an HA Cloud

By , November 1, 2014 7:39 pm

6 months after its debut in Atlanta, the HA workshop happening again in Paris, this Monday (16:20, Room 241)! If you plan on attending and didn’t already see Florian’s blog post, please get downloading and installing the prerequisite files quick, because downloading them over hotel or conference wifi is likely to be painful. (N.B. Unless you have a really strong reason not to, please go with the VirtualBox option, because there are more pitfalls when using KVM+libvirt.)

However if you’re already on the way to Paris, don’t despair, because we’ll also do our best to make the files available at the SUSE booth. And failing that, you can still just turn up, enjoy the show, and then try the hands-on exercise any time later at your own leisure!

In case you have no idea what I’m talking about, here’s some brief history:

Back before the last OpenStack summit in Atlanta in May, I managed to persuade Florian Haas to join me in an endeavour which some might view as slightly insane: run a 90 minute hands-on workshop in which we’d have every attendee build a Highly Available OpenStack cloud on their laptop, from scratch.

With so many moving parts and a vast range of different hardware involved, it certainly wasn’t plain sailing, but by the power of Vagrant and VirtualBox, I think overall it was a success.

Since then, we’ve been working extremely hard to improve the workshop materials based on lessons learnt last time. So what’s new? Well, firstly the workshop environment has been upgraded from Havana Icehouse (SUSE Cloud 4 vs. version 3 in May), and quite a lot of polish has been applied, since in May the HA code was still relatively new.

Secondly, we’ve added support for building the cloud using KVM+libvirt (although VirtualBox is still recommended for a smoother ride).

Thirdly, the documentation is way more comprehensive, and should help you avoid many common pitfalls.

Hope to see you at the workshop, and please come and say hello to us at the SUSE booth!

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How to invite groups of friends to a Facebook event

By , November 7, 2013 12:05 am

Facebook goes some way towards making it easy for you to invite groups of friends to an event, but it still requires a mouse click for each person you want to invite. If you have a friend list containing more than a handful of people, this rapidly gets tedious. Don’t worry though! Here’s a way to select the whole list in one go.

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more uses for git notes, and hidden treasures in Gerrit

By , October 2, 2013 2:05 pm

I recently blogged about some tools I wrote which harness the notes feature of git to help with the process of porting commits from one branch to another. Since then I’ve discovered a couple more consumers of this functionality which are pretty interesting: palaver, and Gerrit.

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Easier upstreaming / back-porting of patch series with git

By , September 19, 2013 9:22 pm

Have you ever needed to port a selection of commits from one git branch to another, but without doing a full merge? This is a common challenge, e.g.

  • forward-porting / upstreaming bugfixes from a stable release branch to a development branch, or
  • back-porting features from a development branch to a stable release branch.

Of course, git already goes quite some way to making this possible:

  • git cherry-pick can port individual commits, or even a range of commits (since git 1.7.2) from anywhere, into the current branch.
  • git cherry can compare a branch with its upstream branch and find which commits have been upstreamed and which haven’t. This command is particularly clever because, thanks to git patch-id, it can correctly spot when a commit has been upstreamed, even when the upstreaming process resulted in changes to the commit message, line numbers, or whitespace.
  • git rebase --onto can transplant a contiguous series of commits onto another branch.

It’s not always that easy …

However, on the occasions when you need to sift through a larger number of commits on one branch, and port them to another branch, complications can arise:

  • If cherry-picking a commit results in changes to its patch context, git patch-id will return a different SHA-1, and subsequent invocations of git cherry will incorrectly tell you that you haven’t yet ported that commit.
  • If you mess something up in the middle of a git rebase, recovery can be awkward, and git rebase --abort will land you back at square one, undoing a lot of your hard work.
  • If the porting process is big enough, it could take days or even weeks, so you need some way of reliably tracking which commits have already been ported and which still need porting. In this case you may well want to adopt a divide-and-conquer approach by sharing out the porting workload between team-mates.
  • The more the two branches have diverged, the more likely it is that conflicts will be encountered during cherry-picking.
  • There may be commits within the range you are looking at which after reviewing, you decide should be excluded from the port, or at least porting them needs to be postponed to a later point.

It could be argued that all of these problems can be avoided with the right branch and release management workflows, and I don’t want to debate that in this post. However, this is the real world, and sometimes it just happens that you have to deal with a porting task which is less than trivial. Well, that happened to me and my team not so long ago, so I’m here to tell you that I have written and published some tools to solve these problems. If that’s of interest, then read on!

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new music video: acoustic version of Jóga by Björk, with Emma Smith

By , September 18, 2013 1:20 pm

I’m a long-time fan of Björk, and was recently lucky enough to snarf a spare ticket to a show here in London at the end of her Biophilia tour. It was a fairly insane show (in a good way), involving an all female Icelandic choir, a drummer, an organ, a musically aware lightning bolt generator, a pin-barrel harp, and David Attenborough (obviously). Really impressive to see how she’s still trail-blazing rather than just churning out the old favourites (although some of the latter were presented in imaginative new ways).

On a related note, back in February I revisited my old haunt the Royal Academy of Music to record/film a version of Björk’s famous tune Jóga, arranged and sang by the amazing and consistently entertaining singer Emma Smith. Yesterday I finally finished the video editing (done with the awesome Kdenlive video editor which is Free Software), and here is the result. Hope you enjoy it!

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