Hello friends! Ivan's here with a slightly delayed July roundup of all things Linux, Containers, Kubernetes, and Server Side 🧙 What I was working on This month, I got nerd-sniped by cgroups. It all started when I ran into a pretty significant difference in how Docker and Kubernetes handle the OOM events. When you limit the memory usage of a multi-process Docker container, the OOM killer often terminates only one of the processes if the container runs out of memory. If this process is not the...
about 1 month ago • 5 min read
Hey there 👋 I spent a few weeks deep diving into cgroup v2, and I'm happy to share my findings with you! Everyone knows that Docker and Kubernetes use cgroups to limit the resources of containers and Pods. But did you know that it's very easy to run an arbitrary Linux process in a cgroup using much more basic tools? The only kernel's interface for cgroups is the virtual filesystem called cgroupfs typically mounted at /sys/fs/cgroup. Creating folders there and writing to files in them is...
about 2 months ago • 1 min read
Hello friends! Ivan's here with the June roundup of all things Linux, Containers, Kubernetes, and Server-Side craft 🧙 What I was working on The first two lessons (and a few challenges) of my "Alternative Introduction to Dagger" course have not sparked much interest among my students, so I had to put this work on pause. With a heavy heart, though, because I do like Dagger, and I was enjoying working on the content about it. But no interest means fewer iximiuz Labs Premium subscribers, and I...
2 months ago • 3 min read
Hello friends! It's time for my traditional monthly roundup of all things Linux, Containers, Kubernetes, and Server-Side craft 🧙 Before we get started, I want you to know that this newsletter's previous issue (dispatched mid-May) was delivered to only about 1/5th of my usual email audience due to an unfortunate DNS misconfiguration. The good news is that you can still find it and all previous issues on newsletter.iximiuz.com. Also, if you reply to this email, it'd help to restore the domain's...
3 months ago • 4 min read
Hello friends! Ivan's here - with another well overdue roundup of all things Linux, Containers, Kubernetes, and Server-Side craft 🧙 This time, I have a great excuse - in April, we became parents of a lovely little boy. Expectedly, he immediately made us overly busy for a few weeks, but no complaints! I wouldn't trade this business for anything else in my life ❤️ Now, to more technical news. What I was working on My main focus remains on iximiuz Labs 🚀 Content authoring redesign In March &...
4 months ago • 10 min read
Hello friends! Ivan's here - with a well overdue February roundup of all things Linux, Containers, Kubernetes, and Server-Side craft 🧙 What I was working on A lot of stuff on the dev side - not so much on the content side. But things are soon to reverse 🤞 Announcing labCTL - the long-awaited iximiuz Labs CLI A dozen people have asked me over the past year-ish if there'll be access to the playgrounds from the local terminal and not only from the browser. And while I myself wanted this feature...
6 months ago • 7 min read
Hello there! 👋 Debugging containerized applications is... challenging. Debugging apps that use slim variants of container images is double challenging. And debugging slim containers in hardened production environments is often close to impossible. Before jumping to the DevOps problems that I prepared for you this week, let's review a few tricks that can be used to troubleshoot containers. If the container has a shell inside, running commands in it with docker exec (or kubectl exec) is...
7 months ago • 1 min read
Hey hey! Are you ready for your next DevOps challenge? Last week, we all witnessed yet another terrifying cyber-security event, and this time, it was a direct hit - researchers from Snyk discovered a way to break out of containers! 🤯 The vulnerability was found in the fundamental component of the containerization ecosystem - the most popular implementation of the (low-level) OCI container runtime - runc. Notice how, on the diagram above, most high-level container runtimes actually rely on the...
7 months ago • 1 min read
Hello friends! Ivan's here - with my traditional monthly roundup of all things Linux, Containers, Kubernetes, and Server-Side craft 🧙 What I was working on After my announcement of the iximiuz Labs GA earlier this month, the platform's usage has more than doubled, so I had to focus on the system's stability and UX. As a result, I increased observability and test coverage, added one more bare-metal server, streamlined a bunch of use cases, and fixed a few bugs. The most notable user-facing...
7 months ago • 3 min read