Custom installation

In the present context, “custom installation” refers to things like manual partitioning, setting up LVM and RAID, and manual LUKS encryption configuration.

Installer Defaults

For reference, these are the typical defaults for a single disk with legacy boot:

Mount Point: /boot
Desired Capacity: 1024 MiB
Device Type: Standard Partition
File System: ext4
Name: (none)

Mount Point: /
Desired Capacity: (your choice)
Device Type: LVM Thin Provisioning
Volume Group: qubes_dom0
File System: ext4
Name: root

Mount Point: (none)
Desired Capacity: 10 GiB
Device Type: LVM
Volume Group: qubes_dom0
File System: swap
Name: swap

SUMMARY OF CHANGES

Order   Action              Type                    Device              Mount point

1       Destroy Format      Unknown                 Disk (sda)
2       Create Format       partition table (MSDOS) Disk (sda)
3       Create Device       partition               sda1 on Disk
4       Create Format       ext4                    sda1 on Disk        /boot
5       Create Device       partition               sda2 on Disk
6       Create Format       LUKS                    sda2 on Disk
7       Create Device       luks/dm-crypt           luks-sda2
8       Create Format       physical volume (LVM)   luks-sda2
9       Create Device       lvmvg                   qubes_dom0
10      Create Device       lvmthinpool             qubes_dom0-pool00
11      Create Device       lvmthinlv               qubes_dom0-root
12      Create Device       lvmlv                   qubes_dom0-swap
13      Create Format       swap                    qubes_dom0-swap
14      Create Format       ext4                    qubes_dom0-root     /

Typical Partition Schemes

If you want your partition/LVM scheme to look like the Qubes default but with a few tweaks, follow this example. With a single disk, the result should look something like this:

NAME                                SIZE    TYPE    MOUNTPOINT
sda                                         disk
├──sda1                               1G    part    /boot
└──sda2                                     part
   └──luks-<UUID>                           crypt
      ├──qubes_dom0-pool00_tmeta            lvm
      ├──qubes_dom0-pool00_tdata            lvm
      └──qubes_dom0-swap                    lvm     [SWAP]

Encryption Defaults

By default, cryptsetup 1.7.5 will create a LUKS/dm-crypt volume as follows:

Version:            1
Cipher name:        aes
Cipher mode:        xts-plain64
Hash spec:          sha256

$ cryptsetup --help
[...]
Default compiled-in device cipher parameters:
        loop-AES: aes, Key 256 bits
        plain: aes-cbc-essiv:sha256, Key: 256 bits, Password hashing: ripdemd160
        LUKS1: aes-xts-plain64, Key: 256 bits, LUKS header hashing: sha256, RNG: /dev/urandom

This means that, by default, Qubes inherits these upstream defaults:

  • AES-128 [1][2][3]

  • SHA-256

  • /dev/urandom

  • probably an iter-time of one second

If, instead, you’d like to use AES-256, SHA-512, /dev/random, and a longer iter-time, for example, you can configure encryption manually by following the instructions below.

Example: Custom LUKS Configuration

Boot into the Qubes installer, then press ctrl+alt+F2 to get a virtual console.

  1. (Optional) Wipe the disk:

    # dd if=/dev/zero of=/dev/sda bs=1M status=progress && sync

  2. Create partitions:

    # fdisk /dev/sda

    Follow the steps to create two partitions:

    • ~500MiB-1GiB for /boot

    • The rest for / (might want to leave some for overprovisioning if it’s an SSD)

  3. Create LUKS encrypted volume:

    # cryptsetup -v --hash sha512 --cipher aes-xts-plain64 --key-size 512 --use-random --iter-time 10000 --verify-passphrase luksFormat /dev/sda2

  4. Open encrypted volume:

    # cryptsetup open /dev/sda2 luks

  5. Create LVM volumes:

    # pvcreate /dev/mapper/luks
# vgcreate qubes_dom0 /dev/mapper/luks
# lvcreate -n swap -L 10G qubes_dom0
# lvcreate -T -l +100%FREE qubes_dom0/pool00
# lvcreate -V1G -T qubes_dom0/pool00 -n root
# lvextend -L <size_of_pool00> /dev/qubes_dom0/root

  6. Proceed with the installer. You can do that either by pressing ctrl+alt+F6, or by rebooting and restarting the installation. At the disk selection screen, select:

    [x] I will configure partitioning.
[ ] Encrypt my data.

  7. Decrypt your partition. After decrypting you may assign mount points: Open the Unknown list and select qubes_dom0-root. Check the reformat box to the right and choose ext4 as a filesystem. Enter / into the Mount Point field at the top. Repeat the process for sda1 and qubes_dom0-swap. Those should be assigned to /boot and swap respectively. The default file systems are ext4 for /boot and /, and swap for swap. When you are finished, the Unknown list should go away, and all three mount points should be assigned. Proceed normally with the installation from there.