encrypt swap Ubuntu 20.04 with hibernation

prerequisite

all command bellow are run has root
install ecryptfs

root@laptop:/root# install apt-get install ecryptfs-utils

encrypt swap

turn off current swap

root@laptop:/root# swapoff -a

encrypt swap partition

root@laptop:/root# cryptsetup luksFormat --cipher aes-xts-plain64 --verify-passphrase --key-size 256 /dev/nvme0n1p2
root@laptop:/root# cryptsetup open /dev/nvme0n1p2 cryptswap

set up the crypt partition as swap.

root@laptop:/root# mkswap /dev/mapper/cryptswap

ajust /etc/fstab to use your mapper, replace your encrypt swap device like bellow :

/dev/mapper/cryptswap   none   swap   discard   0   0

add your encrypt swap device define in /etc/crypttab

cryptswap   /dev/nvme0n1p2		none	luks

enable swap

root@laptop:/root# swapon -a

edit /etc/initramfs-tools/conf.d/resume. Replace the existing RESUME line with the following line.

root@laptop:/root# printf "RESUME=/dev/mapper/cryptswap" | tee /etc/initramfs-tools/conf.d/resume

root@laptop:/root# update-initramfs -u -k all

Change your /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT to point to remove or be sure there is nothing in resume

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

root@laptop:/root# update-grub

disable encrypted swap

root@laptop:/root# swapoff -a
root@laptop:/root# cryptsetup close cryptswap
root@laptop:/root# mkswap /dev/nvme0n1p2
root@laptop:/root# printf "RESUME=/dev/nvme0n1p2" | tee /etc/initramfs-tools/conf.d/resume
root@laptop:/root# update-initramfs -u -k all
root@laptop:/root# update-grub

ajust /etc/fstab to

/dev/nvme0n1p2  none    swap    discard 0       0
#/dev/mapper/cryptswap  none    swap    discard 0       0

check

root@laptop:/root# swapon -a
root@laptop:/root# swapon --summary
Nom de fichier				Type		Taille	Utilisé	Priorité
/dev/nvme0n1p2                         	partition	32653308	0	-2
root@laptop:/root#

to be solve

cryptsetup: ERROR: Couln't resolve device rpool/ROOT/ubuntu_...
cryptsetup: WARNING: Couln't determine root device

- don't work anymore after upgrade form 20.04 to 21.04 on Full ZFS with zfs encrypt and encrypted swap but still work if swap is unencrypted.
- just test it sucessfully again (12.2021) on a 20.04 Full ZFS with zfs unencrypt and encrypted swap.

encrypt swap Ubuntu 20.04 with hibernation

prerequisite

encrypt swap

disable encrypted swap

to be solve

sources