Gentoo on the Google Pixel Pt. 2


I ended up slowing down and taking a while to fully explore all the options in building a Gentoo system on my Pixel. This included me reinstalling from scratch multiple times and learning along the way. This final product is a Pixel install with a 3.12.8 kernel, with the /,/home, and swap partitions sitting in a LVM encrypted with LUKS. Follow through and you will be able to get the same. Also, this install uses the SystemRescueCD (which is based on Gentoo).

Paritioning Drives

Since we are using a SSD for the install, GPT is recommended, which complicates things a tad bit. Using parted, we have to create 3 partitions, the grub-bios partition, /boot, and the 3rd for the LVM. The grub-bios partition is 2MB, the /boot is 512MB (for multiple kernels), and the LVM will be the rest of the drive.

parted -a optimal /dev/sda
mklabel gpt
(parted) unit mib
(parted) mkpart primary 1 3
(parted) name 1 grub
(parted) set 1 bios_grub on
(parted) print
(parted) mkpart primary 3 515
(parted) name 2 boot
(parted) mkpart primary 515 -1
(parted) name 3 rootfs

Encrypting and Creating LVM/File Systems

Encrypt /dev/sda3, mount it and create the LVM

cryptsetup -y --cipher aes-cbc-essiv:sha256 --key-size 256 luksFormat /dev/sda3
cryptsetup luksOpen /dev/sda3 rootfs
pvcreate /dev/mapper/rootfs
lvcreate -L1024m -nswap rootfs
lvcreate -L20480m -nroot rootfs
lvcreate -l 100%FREE home rootfs

Create file systems on the multiple logical volumes you’ve created and mount them to their proper locations:

mkswap -L SWAP /dev/mapper/rootfs-swap
swapon /dev/mapper/rootfs-swap
mkfs.ext4 -j /dev/mapper/rootfs-root -L ROOT
mount /dev/mapper/rootfs-root /mnt/gentoo
mkdir /mnt/gentoo/home
mkfs.ext4 -j /dev/mapper/rootfs-home -L HOME
mount /dev/mapper/rootfs-home /mnt/gentoo/home
mkdir /mnt/gentoo/boot
mkfs.ext4 -j /dev/sda2 -L BOOT
mount /dev/sda2 /mnt/gentoo/boot

Download Gentoo Stage3 tarball

Change directories into /mnt/gentoo, download the stage3 and extract it. Copy over resolv.conf

cd /mnt/gentoo
tar xvjpf stage3-.tar.bz2
cp -L /etc/resolv.conf /mnt/gentoo/etc/

Prepare Portage

nano /mnt/gentoo/etc/portage/make.conf
  CFLAGS="-march=k8 -O2 -pipe"
  mirrorselect -i -o >> /mnt/gentoo/etc/portage/make.conf
  mirrorselect -i -r -o >> /mnt/gentoo/etc/portage/make.conf

Mount Virtual Filesystems

mount -t proc proc /mnt/gentoo/proc
mount --rbind /sys /mnt/gentoo/sys
mount --rbind /dev /mnt/gentoo/dev

Chroot into your new system

chroot /mnt/gentoo /bin/bash
source /etc/profile
export PS1="(chroot) $PS1"

Initialize Portage

emerge --sync

Set up localization information

echo "Continent/Country" > /etc/timezone
emerge --config sys-libs/timezone-data
nano -w /etc/locale.gen
eselect locale list
eselect locale set # Your locale here
env-update && source /etc/profile


At this point I like to install a few apps I use, that way I won’t have to worry about them later. I’d recommend installing vim, NetworkManager (for nmcli), and really anything else you expect to use. I also wanted to use systemd, so I had to prep for that. That includes installing udev with -systemd in make.conf, the installing systemd (obviously remove the - after installing udev), and then uninstalling udev, since systemd provides virtual/udev.

Kernel Setup

  echo "=sys-kernel/gentoo-sources-3.12.8" >> /etc/portage/package.keywords
  emerge gentoo-sources genkernel-next lvm2 cryptsetup grub vim

(As a side note, genkernel-next is required for a systemd install to include udev in the kernel)

vim /etc/genkernel.conf

Create the kernel

genkernel --udev all

Remember to enable support for crypto devices in the kernel, along with anything else you may need/want.

  Device Drivers
    Multi-device support (RAID and LVM)
      [*] Multiple devices driver support (RAID and LVM)
        <*>  Device mapper support
        <*>  Crypt target support

  Cryptographic API 
    <*>  SHA256 digest algorithm
    <*>  AES cipher algorithms

Installing grub2

vim /etc/default/grub
  GRUB_CMDLINE_LINUX="real_init=/usr/lib/systemd/systemd quiet real_root=/dev/mapper/rootfs-root crypt_root=/dev/sda3 dolvm"
grub2-install --modules="configfile linux crypto search_fs_uuid luks lvm" --recheck /dev/sda
grub2-mkconfig -o /boot/grub/grub.cfg

Reboot the machine and you should have a working Gentoo install on your Google Pixel!

Part 3

Asara’s personal blog