luksOpen fails in initramfs

Moriah · Posted: Sat Mar 23, 2024 11:14 pm Post subject:

APPLAUSE !!!
When I corrected /dev/random from block to character device, the SYSTEM BOOTS !!!

Now I need to clean up a few things.

First and foremost, I need to change my network device names from enp0s25 to eth0, and from wlp3s0 to wlan0.

Next I need to force vgmknodes to run, perhaps in /etc/rc.d/rc.local so my LVM device names are listed in /dev.

Then I need mkswap /dev/gentoo/swap to run, also probably in rc.local.

I seem to recall that there is a preferred method instead of rc.local, but I am an old timer, and that's the way I remember doing it before. I haven't built a new kernel in several years, and then it was for a set of hardware-identical machines that serve as routers, firewalls, etc. on my network.

Its really too bad that I let this laptop get so far out of date, but the pandemic and associated pandemonium kept me so busy I didn't have time to risk having something go wrong and mess up my laptop, so I put it of, and off.

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Hu · Moderator Joined: 06 Mar 2007 Posts: 21635

Moriah · Posted: Sun Mar 24, 2024 2:19 am Post subject:

I was trying to avoid having to staticly link yet another executable to run in my initramfs. That is why I wanted to run vgmknodes after the main system started up. Yes, it might be "prettier" to do it in the iniramfs, but it seemed easier to do it when the main system starts up.

When I said "mkswap", I meant to say "swapon".

I do not plan to use hibernation at all. My plan is to use kvm or lxd to create a savable envirionment that I can control manually without having to do a reboot. This will allow me to save a virtual environment for a project, and restore a different virtual environment for a different project at will, without having to reboot. This would be useful when I am supporting multiple clients or project in the same timeframe, and would even allow me to hot-swap my second laptop drive to mount a disk with a different client's project, then restore the saved kvm or lxd environment, again, without having to reboot. This approach can also provide an alternative to hibernation if I need to shut my laptop down and then reboot it later.

Yes, /etc/local.d with stat/stop scripts (mostly start scripts) might be an alternative to rc.local. I currently use rc.local to start my gateway firewall, but I don't recall using it anywhere else lately.

Predictable Network Interface Names is what I am looking to disable so I can use eth0, etc. since I have a number of scripts that rely on those names. Thanks for reminding me what to look for.
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Hu · Moderator Joined: 06 Mar 2007 Posts: 21635

You already put lvm in the initramfs, presumably statically linked. You are using its subcommands for vgchange, among other purposes. lvm vgmknodes would be yet another subcommand, so I think you do not need to add any other programs to your initramfs to be able to use vgmknodes. Just add lvm vgmknodes at the right point in the script.

Moriah · Posted: Sun Mar 24, 2024 11:40 am Post subject:

Good point. What was I thinking? You are right. I will put vgmknodes in the initramfs init script today.
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sublogic · Posted: Mon Mar 25, 2024 12:44 am Post subject:

[Assuming Openrc] the swap is enabled if you declare it in your /etc/fstab and put the swap service in the boot runlevel.

Moriah · Posted: Mon Mar 25, 2024 2:34 am Post subject:

So I put vgmknodes in my init script of my initramfs, and followed it by a ls -l /dev/g* because my volume group is /dev/gentoo, and sure enough, the logical device names were there.

But when the system had completely booted and prompted for a login, I signed in as root and did another ls -l /dev/g* and nothing was there! This surprised me at first, but after thinking about it for a few minutes, I realized that before the chroot in the initscript, /dev is on a filesystem that becomes hidden after the chroot because the vgmknodes was executed before the root filesystem was mounted.

So the bottom line is a need the vgmknodes in my rc.local (or local.d/whatwever) script so it will run after the chroot, as the work done in the initramfs init script gets lost at the chroot.
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Hu · Moderator Joined: 06 Mar 2007 Posts: 21635

If you switch your initramfs to use devtmpfs, and configure the booted system to also use devtmpfs, then changes made to the initramfs dev will be visible in the main system. Also, for certain complex arrangements, the initramfs may need a vgmknodes even if those do not persist into the main system.

Moriah · Posted: Mon Mar 25, 2024 12:03 pm Post subject:

I used to use /dev/tmpfs, but then after a while I started to run into problems with large ebuilds such as rust, etc. so I switched to a disk resident tmpfs, since I almost always have plenty of disk space. I know it is slower, but like the tortoise and the hare, slow and steady wins the race. :wink:

I think I'll stick with using disk for tmpfs for now. Maybe when I get more ram, I'll try /dev/tmpfs again...

Here is my current /etc/fstab:

Hu · Moderator Joined: 06 Mar 2007 Posts: 21635

I think you misunderstand the idea of devtmpfs. It is a kernel-managed filesystem, which happens to use a lot of tmpfs code internally, and it contains the device nodes the kernel thinks it should have, based on current hardware. It is not meant to be writable by ebuilds or users, nor even written by root other than when udev tweaks the kernel defaults. It is not used for backing /dev/shm. It is not used as a general storage area. You seem to be talking about using a regular tmpfs for PORTAGE_TMPDIR, which yes, that can have problems with very large builds. To use devtmpfs, mount it: mount -t devtmpfs devtmpfs /dev. Then the nodes in the resulting /dev are accurate for your hardware.

Moriah · Posted: Mon Mar 25, 2024 3:31 pm Post subject:

So do I mount it before the luksOpen, like /proc and /sys ? Or do I just put it in the dev directory of my initramfs, or what?
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The MyWord KJV Bible tool is at http://www.elilabs.com/~myword

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Hu · Moderator Joined: 06 Mar 2007 Posts: 21635

It is a virtual filesystem, so you cannot store it in the static on-disk directory. Mount it in the same block where you mount the procfs and sysfs virtual filesystems.

Moriah · Posted: Mon Mar 25, 2024 7:19 pm Post subject:

Thanks for the tip on devtmpfs. I put it in the initramfs init script and it works great.

Now for more fun. I did an emerge --sync and got a news item to read. Seems that the devs just released a new profile. :evil:

So I am now making an image backup of my system using dd from the live usb. Running at about 20 GB/min, it should take about 2 hours to finish, then I will follow the directions in the news item to upgrade my profile.
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The MyWord KJV Bible tool is at http://www.elilabs.com/~myword

Foghorn Leghorn is a Warner Bros. cartoon character.

Moriah · Posted: Sun Mar 31, 2024 12:24 am Post subject:

Well, everything is now working under the old profile except alsa sound, specifically alsamixer fails, so something is wrong with my kernel, because it used to work with the old kernel, and the hardware is the same.

I think getting the alsa sound working is a new topic for a new thread, and then I will update the profile per instruction given in the latest news item.

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The MyWord KJV Bible tool is at http://www.elilabs.com/~myword

Foghorn Leghorn is a Warner Bros. cartoon character.