Rootfs over encrypted lvm

This howto describes how to setup LVM, swap, and root with dmcrypt LUKS. It is a standalone installation walk through, based on the official installations finished product. boot is not encrypted.

   Warning

You may try this installation method at your own risk! Please note: this guide is outside of the official installation documentation and cannot be supported. If you choose to use this, we assume you know what you are doing and you are on your own.

Prepare the hard drive and partitions

• Before you begin, make sure you are partitioning the correct drive. For the rest of this tutorial, we will be using /dev/sdX as a placeholder.

root # lsblk
NAME          MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda             8:0    0  1.8T  0 disk 
├─sda1          8:1    0  512M  0 part 
├─sda2          8:2    0    8G  0 part [SWAP]
└─sda3          8:3    0  1.8T  0 part 
  ├─main-root 254:0    0  500G  0 lvm  /
  └─main-data 254:1    0  1.3T  0 lvm  /home

Partition

MBR [BIOS] Partitioning

   Note

Use this method if you are booting using your BIOS, and if your Funtoo LiveCD initial boot menu was light blue. If you're going to use the UEFI/GPT disk format, then please proceed to the next section.

root # fdisk /dev/sdX

Within fdisk, follow these steps:

Empty the partition table:

Command (m for help): o ↵

Create boot partition:

Command (m for help): n ↵
Partition type (default p): ↵
Partition number (1-4, default 1): ↵
First sector: ↵
Last sector: +128M ↵

Create partition which will be encrypted with LUKS:

Command (m for help): n ↵
Partition type (default p): ↵
Partition number (2-4, default 2): ↵
First sector: ↵
Last sector: ↵

Verify the partition table:

Command (m for help): p

Disk /dev/sdX: 298.1 GiB, 320072933376 bytes, 625142448 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x82abc9a6

Device    Boot     Start       End    Blocks  Id System
/dev/sdX1           2048    264191    131072  83 Linux
/dev/sdX2        4458496 625142447 312439128  83 Linux

Write the partition table to disk:

Command (m for help): w

Your new MBR partition table will now be written to your system disk.

UEFI Partitioning

   Note

Use this method if you are interested in booting using UEFI, and if your Funtoo LiveCD initial boot menu was black and white, or the system booted without a boot menu. If it was light blue, this method will not work. Instead, use the instructions in the previous section then skip this section, or reboot LiveCD in UEFI mode first.

root # gdisk /dev/sdX

Within gdisk, follow these steps:

Empty the partition table:

Command: o ↵
This option deletes all partitions and creates a new protective MBR.
Proceed? (Y/N): y ↵

Create boot partition:

Command: n ↵
Partition Number: 1 ↵
First sector: ↵
Last sector: +128M ↵
Hex Code: EF00 ↵

Create partition which will be encrypted with LUKS:

Command: n ↵
Partition Number: 2 ↵
First sector: ↵
Last sector: ↵ (for rest of disk)
Hex Code: ↵

(Optional) Create disk labels:

Command: c ↵
Partition Number: 1
Enter name: BOOT 
Command: c ↵
Partition Number: 2
Enter name: ROOT

Write Partition Table To Disk:

Command: w ↵
Do you want to proceed? (Y/N): Y ↵

The partition table will now be written to the disk and gdisk will close.

Create and mount filesystems.

Create /boot filesystem

For BIOS systems

root # mkfs.ext2 /dev/sdX1

For UEFI systems

root # mkfs.vfat -F 32 /dev/sdX1

Create LUKS encrypted volume

   Note

Cryptsetup now defaults to LUKS2, which is unsupported by stable versions of grub. This is why we are not encrypting /boot.

   Warning

The debian-sources kernel in current stage3 tarballs does not allow for passwords in excess of 63 characters.

root # cryptsetup luksFormat /dev/sdX2

Open newly created LUKS volume

root # cryptsetup open --type luks2 /dev/sdX2 root

Create LVM volumes for / and swap

root # pvcreate /dev/mapper/root

root # vgcreate vg /dev/mapper/root

   Note

Replace "16G" with the amount of swap you would like to make available.

root # lvcreate -L16G --name swap vg

root # lvcreate -l 100%FREE --name root vg

   Note

The "-l 100%FREE" option above will use the remainder of the disk for your root partition. If you would prefer to create separate for /home or /var (for example), you can instead continue to use the "-LXXG" option for fixed sizes.

Create filesystems on LVM volumes

root # mkswap /dev/mapper/vg-swap

root # mkfs.ext4 /dev/mapper/vg-root

Create directories for chroot

root # mkdir -p /mnt/funtoo

Mount filesystems

root # mount /dev/mapper/vg-root /mnt/funtoo

root # mkdir /mnt/funtoo/boot

root # mount /dev/sdX1 /mnt/funtoo/boot

root # mkdir /mnt/funtoo/proc

root # mount -t proc none /mnt/funtoo/proc

root # mkdir /mnt/funtoo/dev

root # mount --rbind /dev /mnt/funtoo/dev

root # mkdir /mnt/funtoo/sys

root # mount --rbind /sys /mnt/funtoo/sys

Set the date

   Note

See the official Funtoo docs on setting the date.

Install the Funtoo starge tarball of your choice

   Note

These instructions will be using the intel-haswell minimal stage3. You should adjust them accordingly

root # cd /mnt/funtoo

root # wget https://build.funtoo.org/1.4-release-std/x86-64bit/intel64-haswell/2021-03-10/stage3-intel64-haswell-1.4-release-std-2021-03-10.tar.xz

root # tar --numeric-owner --xattrs --xattrs-include='*' stage3-intel64-haswell-1.4-release-std-2021-03-10.tar.xz && rm -f stage3-intel64-haswell-1.4-release-std-2021-03-10.tar.xz

Chroot into your new system

root # env -i HOME=/root TERM=$TERM $(which chroot) /mnt/funtoo bash -l

Configure your system

Set a new root password

root # passwd

Set hostname

root # echo 'hostname="yourdesiredhostname"' > /etc/conf.d/hostname

Set up DNS resolution

   Note

We are using the Cloudflare DNS server address here. Feel free to use your own.

root # echo "nameserver 1.1.1.1" > /etc/resolv.conf

Set your timezone

root # ln -sf /usr/share/zoneinfo/YOUR/TIMEZONE /etc/localtime

Note your filesystem information

root # lsblk

/dev/sdX1: UUID="6453-0C55" TYPE="vfat" PARTLABEL="efi" PARTUUID="4e195c4b-f88c-4205-b9df-79a879704b2f"
/dev/sdX2: UUID="aafe709b-82e7-448f-a2cb-36adc3787dc3" TYPE="crypto_LUKS" PARTLABEL="system" PARTUUID="93d0cf9b-0b95-4d8b-919f-48cd1774996f"
/dev/mapper/root: UUID="hvz79n-I2VE-nR1c-0hDQ-PVkR-3GRb-rnuJ9C" TYPE="LVM2_member"
/dev/mapper/vg-swap: UUID="a9188bc3-7def-422b-990d-9de431825779" TYPE="swap"
/dev/mapper/vg-root: UUID="2eaf45e6-d33b-4155-b4ca-63a2fdbfb896" TYPE="ext4"

Configure /etc/fstab

   Note

The UUID parameter is set to the UUID of your boot partition as found from the blkid command above.

root # cat > /etc/fstab << 'EOF'
UUID=6453-0C55 /boot vfat noauto,noatime 1 2
/dev/mapper/vg-swap none swap sw 0 0
/dev/mapper/vg-root / ext4 noatime,nodiratime,defaults 0 1
EOF

Create /etc/crypttab

   Note

The UUID parameter is set to the UUID of /dev/sdX2 as found from the blkid command above.

root # echo "root UUID=aafe709b-82e7-448f-a2cb-36adc3787dc3 none luks,discard" >> /etc/crypttab

Create /etc/dmtab

root # dmsetup table >> /etc/dmtab

Portage

Download the portage tree

root # ego sync

Change your ego profile to include encrypted root support

root # epro mix-in encrypted-root

Edit package USE-flags

root # cat > /etc/portage/package.use <<'EOF'
*/* device-mapper lvm luks
sys-kernel/linux-firmware initramfs
sys-fs/cryptsetup -dynamic
EOF

Install necessary packages

root # emerge grub haveged intel-microcode linux-firmware cryptsetup lvm2 genkernel iucode_tool

Configure services to start at boot

root # rc-update add device-mapper sysinit

root # rc-update add dmcrypt sysinit

root # rc-update add lvmetad sysinit

root # rc-update add haveged default

root # rc-update add busybox-ntpd default

Install a bootloader

Configure /etc/boot.conf

   Note

The UUID parameter is set to the UUID of /dev/sdX2 as found from the blkid command above.

root # cat > /etc/boot.conf <<'EOF'
boot {
    generate grub
    default "Funtoo Linux"
    timeout 3
}
"Funtoo Linux" {
    kernel kernel[-v]
    initrd initramfs[-v]
    params += crypt_root=UUID=aafe709b-82e7-448f-a2cb-36adc3787dc3 dolvm real_root=/dev/mapper/vg-root ro rootfstype=ext4 resume=swap:/dev/mapper/vg-swap quiet
}
EOF

Install GRUB

For BIOS systems

root # grub-install --target=i386-pc --no-floppy /dev/sdX

root # ego boot update

For UEFI systems

root # mount -o remount,rw /sys/firmware/efi/efivars

   Note

For 32 bit systems, the following command should be changed to:

root # grub-install --target=i386-efi --efi-directory=/boot --bootloader-id="Funtoo Linux" --recheck /dev/sdX

root # grub-install --target=x86_64-efi --efi-directory=/boot --bootloader-id="Funtoo Linux" --recheck /dev/sdX

root # ego boot update

Patch genkernel to include LUKS2 support

root # sed '/MODULES_CRYPT/ s/\"$/ af_alg algif_skcipher\"/' -i /usr/share/genkernel/arch/$(arch)/modules_load

Generate a new initramfs

root # genkernel --clean --luks --lvm --disklabel --ramdisk-modules --fullname=$(ls /boot/initramfs-*

Finishing installation

From this point, you should be able to finish following the official Funtoo Linux install instructions

Managing your LUKS volume

Change your LUKs-encrypted drive's passphrase You may want to change your encrypted volume’s passphrase or password from time to time. To do so, run the following commands in the console as root:

root # cryptsetup luksChangeKey /dev/sdx3

You'll be prompted to enter in the existing passphrase first, then to enter in your new passphrase. You will not be asked to confirm your new passphrase, so be careful when running this operation.

Additional links and information

• crypttab
• Root filesystem over LVM2, DM-Crypt, and RAID
• System Encryption with LUKS for dm-crypt
• arch encrypt entire system
• Wikipedia article on LVM
• Arch Wiki article