Filip Chabik

DevOps Engineer, Husband & Dad.

NGINX Extended Security Update (2) →

NGINX before 1.17.7, with certain error_page configurations, allows HTTP request smuggling, as demonstrated by the ability of an attacker to read unauthorized web pages in environments where NGINX is being fronted by a load balancer.

That’s the essence of the CVE-2019-20372. Yet again, as I mentioned in my NGINX Extended post I was not going to work on 1.14.x branch any more with the exception of security updates – this is the case for such exception. Both 1.14.x for Xenial (16.04 LTS) and 1.16.x for Bionic (18.04 LTS) were patched against this vulnerability and are available from my PPA. On Docker Hub I bumped up only the 1.16.x branch as usage for 1.14.x is pretty much non-existent.

Backporting BCC & bpftrace

4th January 2020

I’m following Brendan Gregg’s performance-related content for years now. I started when he was still in Joyent, later on I bought his Systems Performance book and I get back to it whenever I’m doing any profiling. Now I follow closely all of the latest work he’s doing on BPF front. There’s a small problem though. On the dependency tree of production-grade systems, I’ve got the following:

  • stable OS (Debian 10 “Buster” or Ubuntu 18.04 “Bionic Beaver”)
  • latest kernel (5.0+)
  • latest tracing tools (BCC & bpftrace)

Two first are easy – both Debian and Ubuntu are now providing ways for having relatively new kernel up and running – former with buster-backports1 and latter with HWE.2 The third one becomes a small hassle, at least in Ubuntu world.

bpftrace is currently not available for bionic at all. There’s no technical limitation here – it’s just the package was never built for it.3 I decided to backport it then.

  1. Version 5.3.9-2~bpo10+1. 

  2. Version 

  3. In contrast, buster has 0.8+git60-gccac69c2239b-2. 

Dynamic upstreams in NGINX w/ Consul

8th December 2019

I already briefly wrote about the idea of having dynamically discoverable upstreams in NGINX when I covered the topic of NGINX Extended. With the boom of microservices and containers scattered all over the place there was suddenly a need for something that would serve as a single source of truth. When solutions like Mesos/Marathon or Kubernetes kicked in, notion of having services statically assigned to particular address and/or port went straight to the trash. That’s exactly where Consul comes into play. I first crossed my paths with it years ago when it was both relatively new concept and software. These days I think it’s safe to say that, along etcd, it became industry’s standard. But even with its mature state, it solves only half of the problem – it registers and allows services to discover each other for variety of connection purposes, but if there’s anything that needs to serve as an application for HTTPs reverse-proxy, it has to be relatively static. Or does it?

Restic 0.9.6 →

Backups are one of those things that are usually afterthought. Maybe reason for that was a bit too much of necessary configuration or not enough sensible default choices to fit the bill in the older apps I’ve been trying. Either way – this small, single-binary go application simply nails it. All backups are automagically encrypted and deduplicated. These days I tend to setup backups and then just forget about them – they are taken over by restic and it performs its magic on my behalf. Saved my butt few times already.

This release brings no spectacular changes nor features. Which is good, I don’t want my backup solution to have exciting releases – I want bug fixes and small changes and minor enhancements to its matured, stable state. 0.9.6 bring exactly that 🎉