Anyone know who can describe how to get dev-mapper stop halting boot? (LUKS/clevis with /etc/fstab entry)

I've setup'ed clevis9 / LUKS with late boot authentication

sudo systemctl enable clevis-luks-askpass.path

Without any /etc/fstab entry, Ubuntu boots and unlocks the device.

With /dev/mapper entry in /etc/fstab, Ubuntu boot hangs forever with message:

A start job is running for dev-mapper-encryptedfs.device (5min / no limit)

The following /etc/fstab:

UUID=137541e1-4ee0-11e8-b9f6-d45ddf136996 / ext4 defaults 0 0
UUID=F9E1-7C3E /boot/efi vfat defaults 0 0 /swap.img    none    swap    sw  0   0
/dev/mapper/encryptedfs /home/user/luks/encryptedfs ext4    defaults,x-systemd-device-timeout=10   0       0

works OK for normal use, but not boot.

For reference, this is the /etc/crypttab

encryptedfs /dev/sda3 none _netdev

EDIT RESOLUTION: /etc/fstab entry for /dev/mapper/encryptedfs needed to specify _netdev also.

  • I think what is going on is the normal boot process with systemd-fstab-generator that tries to unlock your /dev/mapper/encryptedfs as if it is a normal LUKS partition. May be _netdev is not recognized ? Or may need more configuration? – solsTiCe May 8 '18 at 13:40
  • @solsTiCe I think _netdev is understood because /etc/crypttab entry without /etc/fstab entry works (luks asks for password and clevis provides unlock). – blaufish May 8 '18 at 14:36
  • I don't know but I know for sure I got the same error message, when for an unkown reason, I got /etc/fstab setup to use an encrypted volume while /etc/crypttab was left empty. Changes not saved. Just standard LUKs not clevis one. – solsTiCe May 8 '18 at 14:41
  • @solsTiCe _netdev was needed in /etc/fstab also ^_^ – blaufish May 9 '18 at 6:57


/etc/fstab entry also needed _netdev, i.e.

/dev/mapper/encryptedfs /home/user/luks/encryptedfs ext4    defaults,x-systemd-device-timeout=10,_netdev   0       0

I think what was happing with the old configuration;

  • clevis required _netdev
  • /etc/cryptab entry /dev/mapper/encryptedfs required _netdev
  • /etc/fstab entry started before _netdev but depeded on /dev/mapper/encryptedfs
  • i.e. process started before _netdev, waited on _netdev, and prevented _netdev from starting
  • deadlock

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