FLOSS UK DevOps Conference, Day 2 (26th March)

Stuart Teasdale “Beyond Blue Green – Migrating a legacy application to CI and the Cloud”

Stuart talked us through the story of joining a start-up organisation that was suffering from some infrastructural and development issues around their data logging product; problems such as back-end scaling, inconsistent development practices and poorly specified hosted servers. We were taken through the process of identifying each problem and how it was migrated to modern, consistent processes. Server provision was moved to AWS to take advantage of quick-to-deploy, horizontal scaling and development processes were moved to a continuous integration development pipeline. Stuart ended with a good wrap-up of some of the lessons learned, including failing as early and loudly as possible in your development process and try to keep all instances of the infrastructure as consistent as possible – special cases always cause problems later on.

Richard Melville “An introduction to Btrfs”

Richard gave us an overview of the current state of Btrfs. He took us through the basic Btrfs concepts such as pools and subvolumes and explained the differences between the Btrfs “RAID” levels. He also showed us the ability of using quotas on a per-subvolume level and using snapshots for data protection and replication. Finally there was a run through of how to safely replace a failed drive in a Btrfs RAID pool.

Andrew Beverley “Rexify”

Andrew introduced us to Rex, a configuration management tool. It is similar to Ansible in that you “push” changes to end-nodes (using, SSH, for example) rather than pulling changes from a master server using an agent. Rex is Perl-based which means you can easily leverage existing Perl modules to use in your Rex configuration which is held in “Rexfiles” – similar to Makefiles and installation is as easy as installing the “Rex” module from CPAN. He also took us through some of the other features such as grouping, transaction support (with rollbacks) and referencing external configuration management databases.

Kenneth MacDonald “Kerberos – Protocol and Practice”

Kenneth opened the talk with an overview of Kerberos and a glossary of common terms before giving us a quick run through about how they’re using Kerberos at Edinburgh University and some statistics on their current infrastructure. This was followed by an entertaining physical demonstration of a typical Kerberos session initiation that involved several volunteers passing around envelopes, padlocks and keys that helped to visualise the process.


The conference was closed with raffles for prizes from the attending sponsors and a closing speech from the FLOSS UK chairman. I personally thought this year’s event was particularly well organised and in a city that’s always interesting to visit. I highly recommend the FLOSS Spring conferences to anyone who’s interested in the operational/infrastructural side of open source software and meeting folk with similar interests.

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