| 14 Aug 2022 |
 @grahamc:nixos.org | At this point I can make, upload, and boot an AMI in ~30s, making the most drastically slow step terminating the instance. | 00:35:38 |
 @elvishjerricco:matrix.org | I would love to know more about that, though tonight is a night for things-that-aren't-that :P | 00:36:32 |
| @grahamc:nixos.org | I’m going to bed in a few minutes, and it skips stage-1 anyway … :) | 00:37:00 |
| @elvishjerricco:matrix.org | Y'know, over time, I've stumbled over various little tidbits that make me think we're handling file systems in initrd slightly wrong. And in particular, I've been trying to figure out why I don't have After=local-fs-pre.target on initrd file systems since not having that can fuck with hibernation resumption, and I found this: https://github.com/systemd/systemd/blob/3f504b892b92f54087feeb3fb35e3938567d7fa0/src/core/mount.c#L482-L484 | 03:25:05 |
| @elvishjerricco:matrix.org | I think we're really meant to be using initrd-fs.target the way we've been using local-fs.target | 03:25:59 |
| @elvishjerricco:matrix.org | the problem is that we can't use /etc/fstab to find x-initrd.mount file systems until we've run activation | 03:27:02 |
| @elvishjerricco:matrix.org | Oh holy shit. You can just put fstab in /sysroot/etc/fstab instead of in /etc/fstab as long as you ad x-initrd.mount, and then you don't need all the /sysroot prefix stuff in the fstab stuff, and I bet the initrd dependencies work a bit better | 05:39:18 |
| @elvishjerricco:matrix.org | * Oh holy shit. You can just put fstab in /sysroot/etc/fstab instead of in /etc/fstab in the initrd image as long as you ad x-initrd.mount, and then you don't need all the /sysroot prefix stuff in the fstab stuff, and I bet the initrd dependencies work a bit better | 05:39:37 |
| @elvishjerricco:matrix.org | * Oh holy shit. You can just put fstab in /sysroot/etc/fstab instead of in /etc/fstab in the initrd image as long as you add x-initrd.mount, and then you don't need all the /sysroot prefix stuff in the fstab stuff, and I bet the initrd dependencies work a bit better | 05:39:46 |
| @elvishjerricco:matrix.org | Thank you systemd-fstab-generator for not sanity checking if it makes sense to look at /sysroot/etc/fstab yet... | 05:41:04 |
 Winter (she/her) | is it safe to rely on that though | 06:01:24 |
| @elvishjerricco:matrix.org | I think so | 06:23:09 |
| @elvishjerricco:matrix.org | fstab-generator.c just has a bit of code that basically says "if we're in initrd then go ahead and parse /sysroot/etc/fstab too, with the whole /sysroot thing added in" | 06:25:04 |
| Winter (she/her) | yeah, but what do you mean by the sanity check comment? | 06:25:35 |
| Winter (she/her) | if that behavior is explicit | 06:25:38 |
| @elvishjerricco:matrix.org | more of a joke | 06:25:43 |
| @elvishjerricco:matrix.org | If you think about it for longer than 2 millisecond, it doesn't really make sense to check /sysroot/etc/fstab when /sysroot hasn't been mounted yet | 06:26:06 |
| @elvishjerricco:matrix.org | * If you think about it for longer than 2 milliseconds, it doesn't really make sense to check /sysroot/etc/fstab when /sysroot hasn't been mounted yet | 06:26:12 |
| @elvishjerricco:matrix.org | but it's also harmless and writing code against it would be pointless | 06:26:28 |
| Winter (she/her) | but if the /sysroot behavior is explicit, why wouldn't they mount it before | 06:26:55 |
| Winter (she/her) | i guess i should look at the code | 06:27:04 |
| @elvishjerricco:matrix.org | Winter (she/her): Oh they do | 06:27:06 |
| @elvishjerricco:matrix.org | generators are run twice in initrd | 06:27:13 |
| @elvishjerricco:matrix.org | once before /sysroot is mounted just to get the ball rolling, i.e. parsing /etc/fstab and /proc/cmdline (for root=) | 06:27:37 |
| @elvishjerricco:matrix.org | and once after to check the real root's /etc/fstab for mounts with x-initrd.mount | 06:27:51 |
| @elvishjerricco:matrix.org | (really they don't expect you to use /etc/fstab in initrd; they expect you to tell it where root and /usr are with the cmdline; then they expect all other initrd file systems to come from /sysroot/etc/fstab with x-initrd.mount) | 06:28:52 |
| @elvishjerricco:matrix.org | (which, btw, means systemd technically doesn't want you to have /etc on a file system other than your rootfs) | 06:29:16 |
 K900 | Arguably they don't want you to have an fstab at all\ | 06:29:50 |
| K900 | * Arguably they don't want you to have an fstab at all | 06:29:52 |
| @elvishjerricco:matrix.org | yea well that's a whole other thing :P | 06:30:02 |
