Install Gentoo Linux from Ubuntu

Gentoo is a distribution of Linux which is renowned for its customizability, complexity, package management, and general association with geeky-ness. First and foremost, the Gentoo distribution is not for everyone; be prepared to use your brain as you'll need to do some reading to get your system fully functional. In Gentoo, every package is compiled from source, using their package management tool, portage, so you, the user, decides what features and packages are installed on your system. Compilation/installation of large builds (kde/gnome/libreoffice) can take anywhere between 30 seconds to a few days (each) depending on the hardware used, while smaller builds are installed in a matter of minutes. This guide will allow you to install Gentoo, whilst still leaving your computer completely free for normal everyday use. It was written explicitly to work from Ubuntu, though there is no reason why this will not work from any other Linux distribution.

Steps

  1. Make sure that you have superuser privileges on your Ubuntu box; and an Internet connection - preferably a fast one. An intermediate knowledge of Ubuntu and Linux in general is also preferable.
  2. You need to install chroot on Ubuntu. You can achieve this through Synaptic by installing the dchroot and debootstrap packages; or the command line by typing sudo apt-get install dchroot debootstrap. This program allows Linux to temporarily pretend that its root directory is one different from normal.
  3. Either repartition existing partitions, or create a new partition from free Hard Disk space. Be careful! You don't want to lose any data.
    • Most websites recommend that, essentially, the more partitions, the better. At a minimum, you will need a root partition (/); but most people have a separate swap partition, home partition (/home). Some also recommend a separate partition for /boot and /var.
  4. Format the new partition(s) using a File System of your choice (for /home, /, /boot and /var it is preferable to use ext2, ext3 or reiser2). Swaps need to be formatted as swap partitions.
  5. Create a new folder, /mnt/gentoo and one for each of the separate partitions that you created.
  6. Mount your new partitions on here:
    • sudo mount /dev/sda5 /mnt/gentoo
    • sudo mount /dev/sda6 /mnt/gentoo/home
    where here, sda5 and 6 are the partitions containing your prospective root and home directories respectively.
  7. Check that your date is correct (type date). You can change it with the syntax date MMDDhhmmYYYY.
  8. Open a web browsing program of your choice, and navigate to here. Find your local mirror, and download the stage3 tarball from releases/x86/2008.0/stages/ (replace x86 with the architecture of your choice - this guide is only tested for AMD64 and x86). Download the corresponding md5 file.
  9. Move it to the Gentoo folder mv stage3*.bz2* /mnt/gentoo.
  10. Move yourself there (cd /mnt/gentoo) and check the tarball through md5: md5sum -c stage3*.md5. This makes sure that the tarball downloaded properly without being corrupted. If it doesn't report as OK, then you'll have to re-download it.
  11. Extract the tarball! sudo tar xvjpf stage3*.bz2. Wait for it to complete.
  12. You now have a few basic programs installed on the Gentoo partition; next, you need to install Portage: Gentoo's package management system which allows you to have complete control over what is on your system.
    • Go back to the mirror that you had previously downloaded the stage3 tarball from. Go to the snapshots/ directory, and download the latest Portage file. Move it to /mnt/gentoo, and use the command:
    • tar xvjf /mnt/gentoo/portage-<date>.tar.bz2 -C /mnt/gentoo/usr
    • A brief introduction to Portage: Portage is a package management system allowing for the relatively easy installation of numerous software packages. It works by downloading a list of these and their inter-relationships from an rsync server. This will point portage toward relevant files which can be downloaded from a huge number of other servers. Once these files are downloaded, the software will be compiled from source by your computer - optimising it for your machine.
  13. At this stage, you may want to set some compile flags. You do this by editing /mnt/gentoo/etc/portage/make.conf using your favourite text editor. A full guide on various make variables can be found by reading /mnt/gentoo/usr/share/portage/config/make.conf.example. Save your changes to the configuration file, and exit the text editor.
  14. Want to optimise your download? Edit make.conf again and ensure that the SYNC variable is set to your most local rsync server. Add as many mirrors are you like to the GENTOO_MIRRORS variable - though put your preferred one first. You can find the list of the available mirrors here.
  15. Before you immerse yourself in your new system, you need to make sure that you have a few vital settings copied over from Ubuntu as it is.
    • First, the dns settings: sudo cp -L /etc/resolv.conf /mnt/gentoo/etc/resolv.conf
    • And your proc system: sudo mount -t proc none /mnt/gentoo/proc.
    • And mount-bind the /dev filesystem: sudo mount -o bind /dev /mnt/gentoo/dev.
  16. Now you can chroot! This is simple enough really - and can be exited at any time by typing simply... err... exit. This is a three step process:
    • First, you change the root directory to /mnt/gentoo: sudo chroot /mnt/gentoo /bin/bash.
    • Then, you update the environment in order to ensure that this terminal knows where it's supposed to be: /usr/sbin/env-update
    • Finally, commit this to (temporary) memory: source /etc/profile
    • If you want to remind yourself that you're in chroot, you can use this dainty command: export PS1="(chroot) $PS1"
  17. Congratulations! You're inside Gentoo and about... a quarter of the way there. Chin up!
  18. Next, you need to compile the most vital component of any operating system: its kernel. The kernel is the part of the OS which dictates which pieces of software are allowed access to a piece of hardware at any one moment. Without a kernel, there is no operating system, because it can't operate.
  19. Remember installing portage earlier? Now you're going to download a list of packages which you can install from the rsync server that you specified. Type emerge --sync
  20. For the sake of clarity, at this stage I'll assume that you want to install the latest kernel (2.6) rather than 2.4.
  21. Now we must set our USE flags. These flags tell the compiler what options to add, as well as what optimizations to use. It is important to set the right use flags for your system, otherwise you may end up with some unexpected results. It is also good to add flags that tell what not to add support for.
  22. Every flag you want to add is simply a word. Every option you'd like to remove is the word with a dash (-) in front of it. For example, if we want to compile everything with ogg support, we would add ogg. But if we wanted no ogg support, we would add -ogg.
  23. To choose your USE flags, check out the Gentoo USE Flags documentation to see what flags you might want to include.
  24. Once you have chosen what flags to use, navigate to /etc/make.conf and put in the flags you want.
  25. Let's now set up your timezone. Gentoo has all the time zones at /usr/share/zoneinfo. Navigate to the directory and issue the ls command to view the available timezones. Then copy the timezone to /etc/localtime with a command like (# cp /usr/share/zoneinfo/GMT /etc/localtime).
  26. Now that we have our timezone set up, it is time to actually download our kernel sources and configure the kernel.
  27. Run (# emerge gentoo-sources) to download your kernel sources.
  28. This next step can be tricky for first timers. Here we configure the kernel so that it has whatever support we need. You need to be sure that you set up your kernel correctly, otherwise you may be without functions that you need.
  29. Run
    • cd /usr/src/linux
    • make menuconfig
  30. This will bring up the kernel configuration menu. Be sure to select all the drivers you'll need to boot your system, such as SCSI drivers (if needed), and be sure they are set to be built into the kernel. If they aren't, you won't be able to boot. Also, be sure you enable support for your file system.
  31. Select any network drivers you may need, such as ethernet drivers or wireless drivers (or both).
  32. Choose your processor type and family.
  33. Once you've finished, type ( make && make modules_install) to start compiling the kernel and kernel modules. This may take some time, so go read a book, watch TV, walk the dog, or whatever else you enjoy doing.
  34. make -j2 && make modules_install
  35. Now we need to copy your kernel image to /boot. Change kernel-2.6.24 to whatever you want your kernel to be named. (<code> cp arch/i386/boot/bzImage /boot/kernel-2.6.24)
  36. Now let's configure your kernel modules. Run (find /lib/modules/(kernel version)/ -type f -iname '*.o' -or -iname '*.ko') to find all available kernel modules. Of those, add the ones you want to be auto loaded to /etc/modules.autoload.d/kernel-2.6.Do not include the .ko or .o or the path. Just simply say, for example, snd-hda-intel.

Tips

  • root-groups=root,<host>,portage
  • groups=<host>,portage
  • priority=3
  • Refer to Gentoo Forums, website
  • directory=/mnt/gentoo
  • The stage 3 tarball lacks a "portage" user and group, for some reason, which will cause emerge to fail from inside the chroot. If you use schroot you will have to create the portage user and group on your host system (ubuntu maverick in my case); the passwd and group files in /mnt/gentoo/etc will be overwritten if you modify them directly. After adding the portage user & group to the host system chrooting in the ordinary way should also work with network access. I used schroot with the following configuration:
  • root-users=<host>
  • aliases=gentoo
  • type=directory
  • description=gentoo

Warnings

  • This will take a long time but usually worth it.
  • Do not try to install a cross-architecture version (e.g. gentoo 64 bits on ubuntu 32 bits), as chroot won't work properly (if someone can explain this better ?)

Things You'll Need

  • Ubuntu Ubuntu 10.10(other version are untested)
  • Continuous Internet connection

Related Articles

Sources and Citations

Retrieved from "https://kipkis.com/index.php?title=Install_Gentoo_Linux_from_Ubuntu&oldid=271293"