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Weekly Meeting: 2014-05-27
By Amir Chaudhry - 2014-05-27


  • Mirage on ARM
  • OCaml-Conduit/Ctypes
  • Vchan
  • Irmin/Xenstore
  • Xen Hackathon
  • GSoC/OPW

Attendees: Amir Chaudhry (chair), Thomas Gazagnaire, Thomas Leonard, Anil Madhavapeddy, Mindy Preston and David Scott


Mirage on ARM

Managed to run mir-console on ARM! Sent patches to libm to enable package support and they've been merged so should be in next release. They were very responsive to patches.

ThomasL is currently getting everything working with packages and scripts and other stuff. when ready will send PR to Mirage. Not tried any device drivers yet, just console. Anil is curious if block device works yet - it's straight-forward to debug in the post-mortem. mirage-net-xen might be good to try next. Thomas will have a look. Could get something working by the Xen Hackathon (or at the Hackathon).


Ctypes 0.3.0 was released, with stub generation, which unlocks a bunch of other work that was waiting on it. Anil did a quick release of ocaml-conduit last month and has spent time since then refactoring and improving interfaces. Hoping to get a new release out by the end of the week, which will then unlock a bunch of others e.g. the TLS work, cohttp and a number of others. Anil will update the list when things are settled.


The linking problem mentioned last time was fixed and Dave believes it's all working and Jon can do more at the Hackathon.


Note: Irminsule has been renamed to to Irmin and the repo moved into the Mirage GitHub organisation.

Update on Xenstore and Irmin (Anil wants to call it 'Xirminstore' - no-one else seems keen). Dave, wants to make it fault-tolerant. Will focus on making the interface better and get to a demo for the Xen Hackathon and using Irmin to keep all the logs for debugging.

ThomasG is working on improving the Irmin API so there are some changes coming (Dave has now been warned). A release due very soon and Thomas will be giving a talk on the 6th of June in France. Benjamin Farinier, who's joined for the summer, is also making good progress.

Xen Hackathon

The Xen Developer Hackathon is taking place this week. The schedule is up and there are several topics of interest to us including Docker. You can see the full list on the Xen wiki page.

Anil, ThomasL, Dave and Jon are all registered to go with Nik Sultana on the wait list. There are others who we should talk to at the event including Joao and Filipe about ClickOS and Hwanju about PVH. Could possibly ask the organisers for a Unikernel table. Our aims for the hackathon should be:

  • Get vchan working and Mirage ARM pinging
  • Work on fault-tolerant Xenstore/Irmin
  • Upstream miniOS patches/packages and discuss how best to do this
  • Talk to people about PVH, ARM, suspend/resume and MAC.

Anil notes that we're at risk of turning the hackathon into a chatathon.


Anil wrote a blog post about this summer's Mirage hackers, including those from GSoC and OPW. Intros have been made on the mailing list and they're off to a flying start!

Mindy joined the call this week and she's run through some tests of cohttp. Came up against a roadblock until there's more differentiation of results between invalid requests and invalid pipes. Submitted an issue about this but is aware that there are releases coming soon. Instead she switched over to looking at more client side things. Anil suggested looking at the TCP stack as it's only been tested for the common case and there are probably a lot of issues that could be surfaced. Can't really use Travis for this as it needs a network, which you don't get in a container. Mindy already has a working Xen box so this shouldn't be an issue. You can also read Mindy's recent post on throwing some fuzzy dice to see what she's been up to.


Anil mentioned that it would be fun to get people who are running unikernels (e.g their websites) to automatically be listed on the Mirage site or get some kind of shiny badge for their own. This could be automatic once the TLS libs are usable as it can simply be part of the configuration. Amir laments that his unikernel site is languishing in a Git repo until he can deploy them to the Bytemark machines. Will put this on the agenda for the next call.

Next call will be 10th June and items can be added to the Agenda.