I should learn more about Grub2

July 25, 2016

I have a long-standing dislike of Grub2 (eg, and). Ever since I started having to deal with it I've felt that it's really overcomplicated, and this complexity makes it harder to deal with. There's a lot more to know and learn with Grub2 than there is with the original Grub, and I resent the added complexity for what I feel should be a relatively simple process.

You know what? The world doesn't care what I think. Grub2 is out there and it's what (almost) everyone uses, whether or not I like it. And recent events have shown me that I don't know enough about how it works to really troubleshoot problems with it. As a professional sysadmin, it behooves me to fix this sort of a gap in my knowledge for the same reason that I should fix my lack of knowledge about dpkg and apt.

I'm probably never going to learn enough to become an expert at Grub 2 (among other things, I don't think there's anything we do that requires that much expertise). Right now what I think I should learn is twofold. First, the basic operating principles, things like where Grub 2 stores various bits of itself, how it finds things, and how it boots. Second, a general broad view of the features and syntax it uses for grub.cfg files, to the point where I can read through one and understand generally how it works and what it's doing.

(I did a little bit of this at one point, but much of that knowledge has worn off.)

Unfortunately there's a third level I should also learn about. Grub2 configurations are so complex that they're actually mostly written and updated by scripts like grub2-mkconfig. This means that if I want to really control the contents of my grub.cfg on most systems, I need to understand broadly what those scripts do and what they get controlled by (and thus where they may go wrong). Since I don't think this area is well documented, I expect it to be annoying and thus probably the last bit that I tackle.

(If I cared about building custom grub2 configurations, it should be the first area. But I don't really; I care a lot more about understanding what Grub2 is doing when it boots our machines.)

Written on 25 July 2016.
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Last modified: Mon Jul 25 00:55:21 2016
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