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DevConf.CZ 2019 Recap

·690 words·4 mins·

DevConf.CZ 2019 wrapped up last weekend and it was a great event packed with lots of knowledgeable speakers, an engaging hallway track, and delicious food. This was my first trip to any DevConf and it was my second trip to Brno.

Lots of snow showed up on the second day and more snow arrived later in the week!


First talk of 2019 #

I co-presented a talk with one of my teammates, Nikolai, about some of the fun work we’ve been doing at Red Hat to improve the quality of the Linux kernel in an automated way. The room was full and we had lots of good questions at the end of the talk. We also received some feedback that we could take back to the team to change how we approached certain parts of the kernel testing.


Our project, called Continuous Kernel Integration (CKI), has a goal of reducing the amount of bugs that are merged into the Linux kernel. This requires lots of infrastructure, automation, and testing capabilities. We shared information about our setup, the problems we’ve found, and where we want to go in the future.

Feel free to view our slides and watch the video (which should be up soon.)

Great talks from DevConf #

My favorite talk of the conference was Laura Abbott’s “Monsters, Ghosts, and Bugs.”


It’s the most informative, concise, and sane review of how all the Linux kernels on the planet fit together. From the insanity of linux-next to the wild world of being a Linux distribution kernel maintainer, she helped us all understand the process of how kernels are maintained. She also took time to help the audience understand which kernels are most important to them and how they can make the right decisions about the kernel that will suit their needs. There are plenty of good points in my Twitter thread about her talk.

Dan Walsh gave a detailed overview of how to use Podman instead of Docker. He talked about the project’s origins and some of the incorrect assumptions that many people have (that running containers means only running Docker). Running containers without root has plenty of benefits. In addition, a significant amount of work has been done to speed up container pulls and pushes in Podman. I took some notes on Dan’s talk in a thread on Twitter.

The firewalld package has gained some new features recently and it’s poised to fully take advantage of nftables in Fedora 31! Using nftables means that firewall updates are done faster with fewer hiccups in busy environments (think OpenStack and Kubernetes). In addition, nftables can apply rules to IPv4 and IPv6 simultaneously, depeending on your preferences. My firewalld Twitter thread has more details from the talk.

The cgroups v2 subsystem was a popular topic in a few of the talks I visited, including the lightning talks. There are plenty of issues to get it working with Kubernetes and container management systems. It’s also missing the freezer capability from the original cgroups implementation. Without that, pausing a container, or using technology like CRIU, simply won’t work. Nobody could name a Linux distribution that has cgroups v2 enabled at the moment, and that’s not helping the effort move forward. Look for more news on this soon.


OpenShift is quickly moving towards offering multiple architectures as a first class product feature. That would incluve aarch64, ppc64le, and s390x in addition to the existing x86_64 support. Andy McCrae and Jeff Young had a talk detailing many of the challenges along with lots of punny references to various “arches”. I made a Twitter thread of the main points from the OpenShift talk.

Some of the other news included:

  • real-time linux patches are likely going to be merged into mainline. (only 15 years in the making!)
  • Fedora, CentOS, RHEL and EPEL communities are eager to bring more of their processes together and make it easier for contributors to join in.
  • Linux 5.0 is no more exciting than 4.20. It would have been 4.21 if Linus had an extra finger or toe.

DevConf.US Boston 2019 #

The next DevConf.US is in Boston, USA this summer. I hope to see you there!