void-linux / void-linux/void-docs

FDE guide: Use UUID instead of `/dev/sda*` in crypttab

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Description

The FDE guide here currently shows the following example /etc/crypttab:

voidvm   /dev/sda1   /boot/volume.key   luks

This should be changed to using the UUID of the encrypted device/partition, as the device file names dev/sdx are not deterministic.

Some user on #voidlinux just had an issue where the key file in the initramfs would sometimes not be picked up, and they were asked to enter a passphrase instead. I think this might be because they had /dev/sda1 in their /etc/crypttab like the guide suggests. They reported that using /dev/disk/by-uuid/* worked.

I think dracut also understands some other syntax like UUID=... and even luks-..., but I'm not sure which one is best/correct here. I think the relevant dracut module is /usr/lib/dracut/modules.d/90crypt.

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the FDE guide section linked in the issue and inspect its /etc/crypttab example. Check the referenced dracut module at /usr/lib/dracut/modules.d/90crypt to determine the supported UUID syntax, then update the example so it uses a deterministic device identifier and verify the guide's wording is consistent.

Written by the indexing model from the issue text.

Assessment

Tech stack
linux
Domain
documentation, operating-systems
Issue type
Documentation
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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