Open LVM volumes after reboot on live USB

To access an encrypted disk from a live USB, execute:

1. cryptsetup luksOpen /dev/nvme0n1p3 lvm
2. vgscan --cache
3. vgchange -a y

Chrooting

1. Create a directory for the new Gentoo installation and mount the root LVM volume to it:
   • mkdir /mnt/gentoo
   • mount /dev/mapper/vg0-root /mnt/gentoo
2. Copy DNS info (to ensure Internet is working once chrooted to /mnt/gentoo):
   • cp --dereference /etc/resolv.conf /mnt/gentoo/etc/
3. Mount necessary file systems:
   • mount --types proc /proc /mnt/gentoo/proc
   • mount --rbind /sys /mnt/gentoo/sys
   • mount --make-rslave /mnt/gentoo/sys
   • mount --rbind /dev /mnt/gentoo/dev
   • mount --make-rslave /mnt/gentoo/dev
   • mount --bind /run /mnt/gentoo/run
   • mount --make-slave /mnt/gentoo/run
     • or as one command:
       • sudo mount --types proc /proc /mnt/gentoo/proc && sudo mount --rbind /sys /mnt/gentoo/sys && sudo mount --make-rslave /mnt/gentoo/sys && sudo mount --rbind /dev /mnt/gentoo/dev && sudo sudo mount --make-rslave /mnt/gentoo/dev && sudo mount --bind /run /mnt/gentoo/run && sudo mount --make-slave /mnt/gentoo/run
   • If your distribution (Ubuntu Live USB) has /dev/shm being a symbolic link to /run/shm/, you need to also execute:
     • test -L /dev/shm && rm /dev/shm && mkdir /dev/shm
     • mount --types tmpfs --options nosuid,nodev,noexec shm /dev/shm
     • chmod 1777 /dev/shm /run/shm
4. Enter the new environment:
   • Change the root location: chroot /mnt/gentoo /bin/bash
   • Reload settings: source /etc/profile
   • Change primary prompt name: export PS1="(chroot) ${PS1}"
5. Mount boot partition:
   • mount /dev/nvme0n1p1 /boot