Installing Gentoo: One Month Later

May 28, 2018

It seems that the general consensus on "distro hopping," the act of constantly switching between distributions of GNU/Linux, is that it's a bad habit that should be consciously avoided. If you do a search for the term, you'll get articles with titles along the lines of "How I Stopped Distro Hopping." But it's also a term that gets thrown around loosely, and I think that that "distro hopping" is an acceptable practice in a lot of the contexts where the phrase is used. Needless to say, I've "hopped" distributions in the past month, and this blog post is going to describe the highs and lows of that experience.

My experiences with GNU/Linux began when I installed openSUSE about four years ago. I chose it over something more conventional like Ubuntu for its integration with KDE Plasma 4 (I'm aware that I suffered from bad taste at the time). I stuck with that until I decided to try Fedora for no particular reason, which was short-lived. I later switched to Arch Linux to fit in with the cool kids, and that became my daily driver for a little over two years. Recently, however, I've switched to Gentoo, because I've wanted to try GNU/Linux without systemd and friends. Many conversations with people over IRC convinced me that the maintenance model of those packages is concerning, to say the least, and that it's preferable if the operations-critical parts of my operating system aren't ridden with CVE's. Gutting Arch of the beasts within is possible, but seriously complicates everything, so I decided that the best course of action was to just throw the baby out with the bathwater and use this as an opportunity to experiment with something I'd been meaning to try.

Gentoo has been on my radar ever since I installed Arch, as I had several friends who loved to talk about the merits of a source-based distribution. My original plan was to wait until I had a machine I could comfortably experiment with, separate from my workstation or laptop, but since I was hopping distros anyway, I decided to just go ahead and get my hands dirty. Of course, I didn't go into the whole migration process without concerns. For one, I want to cleanse all of machines of systemd. That includes the Raspberry Pi I use as a home server, and I don't think it's powerful enough to be compiling everything from source. I opted to install Alpine on that instead. The other problem was that my laptop's only storage device was an SSD, which I didn't want to subject to excessive writes. Fortunately the solution to that was straightforward: I was able to mount =/var/tmp/portage'=as tmpfs so that all the object files generated while compiling got dumped to an in-memory filesystem instead of the disk.

After making sure that everything I needed to do was possible on the new setup, I went ahead and installed it on both my workstation and laptop. The canonical reference for installing Gentoo, dubbed "the handbook," is incredibly well-written, so the installation process was painless. I think the quality of documentation is a big benefit that Gentoo has over Arch; everyone praises the Arch wiki, but I find that the Gentoo documentation is far more informative and much more consistent. Setting it up past the initial installation really wasn't difficult either - I had X11 running the same night.

I also used this as an opportunity to try out some new software. On Arch, I was using i3 and rxvt-unicode, but now I'm on dwm and st and I'm really enjoying both of them. These programs are configured at compile-time, which would've made using them on Arch a bit unwieldy, but Gentoo's package manager makes the whole process trivial. I just throw any patches I want in /etc/portage/patches, edit the config.h files in /etc/portage/savedconfig, and emerge the package.

Gentoo's package manager is by far the best I've used in my four years of running GNU/Linux. Being able to interface with it through a couple of files in /etc is a great interface. It also brings USE flags, which is probably the poster child of Gentoo's features. If you're not familiar with USE flags, they allow you to enable or disable certain features at compile-time. As an example, say I want to play some Goldeneye on my Nintendo 64 and use my computer as a monitor. I have a cheap USB capture card with a kernel driver exposing the Video4Linux API. I'll need some sort of video player to put the stream on my monitor, but that video player is going to need to come with support for said Video4Linux API. I'm what you might call a special case - most GNU/Linux users don't have capture cards, so that feature isn't important to them. If it isn't important to them, why should they have to waste disk space housing all the code and dependencies for it? This is where conditional-compilation comes in. During the process of turning source code into executable binaries, certain features can be turned on or off. In a binary distribution like Arch Linux, the package maintainers need to make an executive decision about which features should be enabled, because they're making a binary for everyone. And, last I checked, they decided that V4L support wasn't important enough for them to enable it. Bummer. If you want that feature, you'll need to compile it yourself. And if a package has features you don't care about, bummer. You have to either deal with all the dependencies that those features bring in, or compile it yourself.

USE flags makes this a lot easier by integrating conditional compilation options into the package manager, rather than forcing you to wrangle with the configure script of whatever build system the software uses. For example, I can compile mpv with support for V4L simply by enabling the 'v4l' USE flag. The nice thing about this is that all packages supporting V4L recognize this same USE flag, and I can enable it globally - compiling V4L support into everything on my system without putting much thought into it. And if I just want it for mpv instead of everything on my system, I'm also able to enable it for just certain packages.

This freedom does come with the downsides of, well, having to compile everything from source. Compiling software takes time and processing power, and trying to optimize the process has caused me some headaches. In Gentoo, you'll want to pick a decent value for --jobs in make.conf so that compilation is fast. --jobs, or -j is a signal to the build system that it can run some number of tasks in parallel. I started out with -j8 on my laptop, since it has 8 cores. This worked great for smaller packages, but when I tried to emerge Firefox, my machine gave up half-way through. It was still running. I could Ctrl+Z from emerge and use it, but the compilation process had hanged and my only option was to restart it, to which it would hang at another point in the compilation process. I tried it again with -j4 and it was able to compile without any trouble, it just took much longer. I had a similar issue on my workstation - it has a quad-core processor so I was using -j4, but I was regularly getting segmentation faults while emerging large packages such as LLVM (apparently a hardware issue that I need to look into), so I lowered it to -j2. Of course, looking back on it now, the number of cores your machine has isn't a good value for '-j' anyway.

Another great thing about Portage is the API for making your own packages. It's shell scripts, so it's similar to how you'd go about making a package on Arch, but I find the API feels like a massive hack. For one, the documentation, again, towers over that of Arch, but it also brings something reminiscent of a standard library: eclasses, which enable you to abstract the commonality between packages using the same build system. Also, instead of having just one big AUR, unofficially maintained packages are distributed in user-managed "overlays." I'd think that pacman can probably do something similar, but you almost never see it in practice.

All in all, I'm very happy with the level of customization and freedom that Gentoo offers me, and I haven't missed systemd one bit. OpenRC, ALSA, and wpasupplicant are all I need. Going forward, I'm hoping to become more involved in the Gentoo community - becoming active on the forums and IRC, and hosting an overlay for the handful of ebuilds I've made. The Gentoo community seems much more tightly-knit than the Arch community, and I'm looking forward to meeting some new friends.

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