Another year, another FOSDEM edition. As always, since this conference grew so big (fact: if you tried to watch all videos in a row, it'll take you about 9 weeks!), chances are, every review you read from the conference will contain something different, and therefore, complementary.

This is what I was able to experience. Let's take a look.

A recurrent theme in FOSDEM seems to be the high concurrency. There were lots of people attending, which made it difficult to make it into some dev-rooms, as they were overcrowded. In addition, some very popular dev-rooms got regular-size rooms where not enough people could fit (for example the PostgreSQL one, as opposed to last year). Because of this, I missed quite a few opportunities.

However, another trait of the conference is not only the high concurrency, but also the high quality of the talks. Therefore, falling back to some any other talk ended up on me learning about some cool topic, with the added element of surprise.

The Talks

On Saturday, I started the morning in the free Java dev-room, and the first talk I watched was Tornado VM: A Java VM for heterogeneous hardware. It introduced the idea of having a VM that takes advantage of different hardware (not just CPU, but also GPUs, and FPGAs as well). Though it was Java-focused, it did mention that the concepts are applicable to other languages as well.

The followed a talk about ByteBuffers. A really nice presentation of the new memory management API (coming up to Java 14). It presented the rationale, common performance issues, the goals of accessing memory on and off the heap, and such.

Afterwards, I went to the The Hidden Early History of Unix.

One of the highlights of the conference was Fixing the Kubernetes clusterfuck. An amazing talk (I highly recommend you watch the video), with a live demonstration of how to hack (and detect) a Kubernetes cluster. It started with a very good introduction to the falco project (how it's built, how it works, how it integrates with another tools, and its capabilities). It's a project with interesting features (like for instance the fact that uses eBPF makes it have a minimal overhead).

The next three talks continued with the security theme. The first one of them also about containers: Using SELinux with container runtimes, The hairy issue of e2e encryption in instant messaging, and What you most likely did not know about sudo.

And that closed up the first day.

On Sunday, I started by attending two talks about monitoring and observability. On [Distributed tracing for beginners]{.title-ref} we saw a live demo of applying tracing to a Java application, from the ground up, and seeing the metrics with Jaeger. Then came a talk about Grafana: successfully correlate metics, logs, and traces which was a very good continuation. It was also interesting to learn about upcoming features to Grafana (such as linking to traces from the metrics graphs directly, and more integrations).

Afterwards, I attended another talk about SWIM - Protocol to build a cluster, and on the same room came the talk about Implementing protections against Speculative Execution side channel: a really technical and well-presented talk explaining low-level security implications of side channel attacks, and some recommendations on how to avoid some of those issues. The talk introduced the MDS / TAA threat models, and their implications. There were also really good questions asked at the end, that provided very interesting food for thought.

On the evening, I was able to finally make it into the PostgreSQL dev-room, and it was really worth it. The first talk was about The state of full-text search on PostgreSQL 12. It properly explained some of the internals that go on, when we try to use this feature, and some caveats to avoid. It had a really nice introduction to information retrieval, and how it's implemented in PostgreSQL.

Finally, RTFM (don't be misled --as I was--, by the title), presented four case studies on which things went south, and why. The learnings on all cases, provided valuable insights on how to make a better use of our relational database.

Then came the closing talk, celebrating the 20 years of the conference.

All in all, another good edition of the European conference for open source. There's still lots of material that I would like to go over in more detail, and some missed talks that I have to catch up on, but it was a good experience.