Difference between pages "Welcome" and "Rootfs over encrypted lvm"

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This howto describes how to setup LVM and rootfs with cryptoLUKS-encrypted drive. It is not meant to be a standalone installation guide, rather, it is meant to be read alongside the [[Funtoo Linux Installation]] Guide.
{{#Widget:MonthlyDonate}}
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<div class="boxy">
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== Featured Video ==
+
  
In this video, Jonathan Vasquez ([[User:Fearedbliss|fearedbliss]]) walks you through the process of installing Funtoo Linux with ZFS. See the [[ZFS Install Guide]] for detailed instructions.
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== Prepare the hard drive and partitions ==
{{#widget:YouTube|id=kxEdSXwU0ZI|width=320|height=180}}
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This is an example partition scheme, you may want to choose differently.
</div>
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<code>/dev/sda1</code> used as <code>/boot</code>. <code>/dev/sda2</code> will be encrypted drive with LVM.
<div class="boxy">
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* <code>/dev/sda1</code> -- <code>/boot</code> partition.
== Get on the UserMap! ==
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* <code>/dev/sda2</code> -- BIOS boot partition (not needed for MBR - only needed if you are using GPT) This step required for GRUB2. For more info, see: [http://www.funtoo.org/Funtoo_Linux_Installation#Prepare_Hard_Disk] for more information on GPT and MBR.
{{#compound_query:[[Category:People]] [[Role type::Staff]];?Geoloc;icon=Purplemarker.png;limit=9999
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* <code>/dev/sda3</code> -- <code>/</code> partition, will be the drive with LUKS and LVM.
    |[[Category:People]][[Role type::Contributor]];?Geoloc;icon=Orangemarker.png;limit=9999
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    |[[Category:People]][[Role type::User]];?Geoloc;icon=Greenmarker.png;limit=9999
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    |format=googlemaps3|height=275|zoom=1|type=hybrid|markercluster=yes}}
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See our full-size [[Usermap]] and find out how to become part of the Funtoo Universe!
+
</div>
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</div>
+
  
== What is Funtoo Linux? ==
+
=== Wipe the hard drive ===
 +
{{Fancywarning|This action will destroy all data on the disk.}}
 +
<console>
 +
# ##i##gdisk /dev/sda
  
[[Funtoo Linux]] is a Linux-based operating system created by [[user:Drobbins|Daniel Robbins]], the creator and former Chief Architect of Gentoo Linux. Funtoo Linux is a Free software, or "Open Source" operating system. All distribution source code is freely available, and it can be used and distributed free of charge.
+
Command: ##i##x ↵
 +
Expert command: ##i##z ↵
 +
About to wipe out GPT on /dev/sda. Proceed?: ##i##y ↵
 +
GPT data structures destroyed! You may now partition the disk using fdisk or other utilities.
 +
Blank out MBR?: ##i##y ↵
 +
</console>
  
Who develops and improves Funtoo Linux? '''You do.''' We are a completely open meta-distribution that is run by our users and a small group of support staff. Our development centers around the needs of our users. Any user can contribute code and help improve Funtoo Linux functionality on our [http://bugs.funtoo.org bug tracker].
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{{Note}} You will get a message about reaching the end of the device when the <code>dd</code> command has finished. This behavior is intended.
<div>
+
  
== What's New? ==
+
== Encrypting the drive ==
 +
Read more about different cipher options here: [http://blog.wpkg.org/2009/04/23/cipher-benchmark-for-dm-crypt-luks/]
 +
<console>
 +
# ##i##cryptsetup --cipher aes-xts-plain64 luksFormat /dev/sda3
 +
# ##i##cryptsetup luksOpen /dev/sda3 dmcrypt_root
 +
</console>
  
{{Note}} Feb 12, 2014: '''Clean GNOME 3.6 merges''' from funtoo-gnome-overlay hit Portage tree, '''GNOME 3.10''' on horizon -- [https://groups.google.com/d/msg/funtoo-dev/4JLeMOn-xMk/SifhK2GsiBgJ Learn more here]...
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There you'll be prompted to enter your password phrase for encrypted drive, type your paranoid password there.
  
== Resources ==
+
= Create logical volumes =
 +
<console>
 +
# ##i##pvcreate /dev/mapper/dmcrypt_root
 +
# ##i##vgcreate vg /dev/mapper/dmcrypt_root
 +
# ##i##lvcreate -L10G --name root vg         
 +
# ##i##lvcreate -L2G --name swap vg
 +
# ##i##lvcreate -L5G --name portage vg
 +
# ##i##lvcreate -l 100%FREE -nhome vg
 +
</console>
 +
Feel free to specify your desired size by altering the numbers after the -L flag. For example, to make your portage dataset 20GB's, use the flag -L20G instead of -L5G.
  
* Learn more about [[Funtoo Linux]].
+
= Create a filesystem on volumes =
* Why you should [[Choose Funtoo]]: ...and how it is different from other distros.
+
<console>
* Visit [[:Category:Projects|Funtoo Linux Projects]] and also look at the stuff online for [[Metro]].
+
# ##i##mkfs.ext2 /dev/sda1
* Learn [[:Category:Linux Core Concepts| Core Linux concepts]] from articles originally written by Daniel Robbins.
+
# ##i##mkswap /dev/mapper/vg-swap
* [[Funtoo Linux Installation|Install Funtoo Linux]]
+
# ##i##mkfs.ext4 /dev/mapper/vg-root
Funtoo Linux is focused on the needs of our users. Here's how to get involved:
+
# ##i##mkfs.ext4 /dev/mapper/vg-portage
 +
# ##i##mkfs.ext4 /dev/mapper/vg-home
 +
</console>
  
* '''wiki''': Help us maintain content on this wiki. Add yourself to the Funtoo [[Usermap]].
+
= Basic system setup =
* '''bugs''': Our [http://bugs.funtoo.org bug tracker] is used to track all ongoing development work in Funtoo Linux. If you find a bug in Funtoo Linux, report it here. Also used for enhancement requests.
+
<console>
* '''IRC''': Join us in the <tt>#funtoo</tt> IRC channel on <tt>irc.freenode.net</tt>.
+
# ##i##swapon /dev/mapper/vg-swap
* '''mailing list''': The [https://groups.google.com/forum/#!forum/funtoo-dev funtoo-dev mailing list] is used for development discussion.
+
# ##i##mkdir /mnt/funtoo
* '''forums''': [http://forums.funtoo.org Funtoo Forums] are available for forum-style Funtoo discussion.
+
# ##i##mount /dev/mapper/vg-root /mnt/funtoo
* '''blogs''': [http://larrythecow.org LarryTheCow.org] is a blog aggregation service for Gentoo ecosystem developers and users.
+
# ##i##mkdir -p /mnt/funtoo/{boot,usr/portage,home}
* '''rss/atom''': [[Funtoo RSS and Atom Feeds]] displays the latest posts on the Forums and Planet Larry.
+
# ##i##mount /dev/sda1 /mnt/funtoo/boot
 +
# ##i##mount /dev/mapper/vg-portage /mnt/funtoo/usr/portage
 +
# ##i##mount /dev/mapper/vg-home /mnt/funtoo/home
 +
</console>
 +
Now perform all the steps required for basic system install, please follow [http://docs.funtoo.org/wiki/Funtoo_Linux_Installation]
 +
don't forget to emerge the following before your install is finished:
  
__NOTOC__
+
* '''cryptsetup'''
__NOTITLE__
+
* '''lvm2'''
__NOEDITSECTION__
+
* '''a bootloader (grub recommended)'''
 +
* '''kernel sources '''
  
[[Category:Funtoo|*]]
+
= Editing the fstab =
 +
Fire up your favorite text editor to edit <code>/etc/fstab</code>. You want to put the following in the file:
 +
{{File
 +
|/etc/fstab|<pre>
 +
# <fs>                  <mountpoint>  <type>    <opts>                          <dump/pass>
 +
/dev/sda1              /boot        ext2      noauto,noatime                  1 2
 +
/dev/mapper/vg-swap    none          swap      sw                              0 0
 +
/dev/mapper/vg-root    /            ext4      noatime,nodiratime,defaults    0 1
 +
/dev/sr0                /mnt/cdrom    auto      noauto,ro                      0 0
 +
/dev/mapper/vg-portage  /usr/portage  ext4      noatime,nodiratime              0 0
 +
/dev/mapper/vg-home    /home        ext4      noatime,nodiratime              0 0
 +
</pre>}}
 +
 
 +
= Kernel options =
 +
{{Note}}This part is particularly important: pay close attention.
 +
{{kernelop
 +
| <br> |<pre>
 +
General setup --->
 +
      [*] Initial RAM filesystem and RAM disk (initramfs/initrd) support
 +
</pre>}}
 +
 
 +
{{kernelop
 +
| <br> |<pre>
 +
Device Drivers --->
 +
      Generic Driver Options --->
 +
      [*] Maintain a devtmpfs filesystem to mount at /dev
 +
</pre>}}
 +
 
 +
{{kernelop
 +
| <br> |<pre>
 +
Device Drivers --->
 +
      [*] Multiple devices driver support --->
 +
      <*>Device Mapper Support
 +
        <*> Crypt target support
 +
</pre>}}
 +
 
 +
{{kernelop
 +
| <br> |<pre>
 +
Cryptographic API --->
 +
      <*> XTS support
 +
      -*-AES cipher algorithms
 +
</pre>}}
 +
 
 +
= Initramfs setup and configuration =
 +
== Better-initramfs ==
 +
'''Build your initramfs with [https://bitbucket.org/piotrkarbowski/better-initramfs better-initramfs] project.'''
 +
 
 +
{{Note}} better-initramfs supports neither dynamic modules nor udev, so you should compile your kernel with built-in support for your block devices and file system support.
 +
 
 +
<console>
 +
# ##i##cd /opt
 +
# ##i##git clone git://github.com/slashbeast/better-initramfs.git
 +
# ##i##cd better-initramfs
 +
# ##i##less README.rst
 +
# ##i##bootstrap/bootstrap-all
 +
# ##i##make prepare
 +
# ##i##make image
 +
</console>
 +
 
 +
Copy resulting <code>initramfs.cpio.gz</code> to <code>/boot</code>:
 +
<console># ##i##cp output/initramfs.cpio.gz /boot</console>
 +
 
 +
Alternatively, a pre-compiled binary initramfs is available at https://bitbucket.org/piotrkarbowski/better-initramfs/downloads
 +
<console>
 +
# ##i##wget https://bitbucket.org/piotrkarbowski/better-initramfs/downloads/release-x86_64-v0.7.2.tar.bz2
 +
# ##i##tar xf release-x86_64-v0.5.tar.bz2
 +
# ##i##cd release*
 +
# ##i##gzip initramfs.cpio
 +
# ##i##cp initramfs.cpio.gz /boot
 +
</console>
 +
 
 +
Remember, better-initramfs project is a work in progress, so you need to update from time to time. It can be done easily with <code>git</code>. Go to the better-initramfs source dir and follow:
 +
<console>
 +
# ##i##cd /opt/better-initramfs
 +
# ##i##git pull
 +
# ##i##less ChangeLog
 +
</console>
 +
{{Note}}Please read the ChangeLog carefuly and perform necessary updates to <code>/etc/boot.conf</code>. Also, please backup the working <code>/boot/initramfs.cpio.gz</code> and <code>/etc/boot.conf</code> before updating better-initramfs.
 +
 
 +
== Genkernel ==
 +
Funtoo's genkernel capable to create initramfs for encrypted drive. Compile and install kernel and initramfs of your favorite kernel sources:
 +
<console>
 +
# ##i##genkernel --kernel-config=/path/to/your/custom-kernel-config --no-mrproper --makeopts=-j5 --install --lvm --luks all </console>
 +
 
 +
== Bootloader Configuration ==
 +
=== Grub2 configuration ===
 +
==== better-initramfs ====
 +
An example <code>/etc/boot.conf</code> for better-initramfs:
 +
 
 +
{{File
 +
|/etc/boot.conf|<pre>
 +
boot {
 +
  generate grub
 +
  default "Funtoo Linux"
 +
  timeout 3
 +
}
 +
"Funtoo Linux" {
 +
  kernel vmlinuz[-v]
 +
  initrd /initramfs.cpio.gz
 +
  params += enc_root=/dev/sda3 lvm luks root=/dev/mapper/vg-root  rootfstype=ext4 resume=swap:/dev/mapper/vg-swap quiet
 +
</pre>}}
 +
 
 +
Now, run <code>boot-update</code> to write the configuration files to <code>/boot/grub/grub.cfg</code>
 +
 
 +
==== genkernel ====
 +
Configure the bootloader as described above, with correct kernel and initramfs images names. An example for genkernel and grub2. You will be editing <code>/etc/boot.conf</code>:
 +
 
 +
{{File
 +
|/etc/boot.conf|<pre>
 +
boot {
 +
  generate grub
 +
  default "Funtoo Linux"
 +
  timeout 3
 +
}
 +
"Funtoo Linux" {
 +
  kernel kernel-genkernel-x86_64-3.13.0
 +
  initrd initramfs-genkernel-x86_64-3.13.0
 +
  params += crypt_root=/dev/sda3 dolvm real_root=/dev/mapper/vg-root  rootfstype=ext4 resume=swap:/dev/mapper/vg-swap quiet
 +
</pre>}}
 +
 
 +
== Lilo configuration ==
 +
For oldschool geeks, an example for lilo bootloader. Emerge lilo with device-mapper support
 +
<console>
 +
# ##i##echo 'sys-boot/lilo device-mapper' >> /etc/portage/package.use/lilo
 +
# ##i##emerge lilo
 +
</console>
 +
 
 +
Example <code>/etc/lilo.conf</code>:
 +
 
 +
{{File
 +
|/etc/lilo.conf|<pre>
 +
append="init=/linuxrc dolvm crypt_root=/dev/sda2 real_root=/dev/mapper/vg-root"
 +
boot=/dev/sda
 +
compact
 +
default=funtoo
 +
lba32
 +
prompt
 +
read-only
 +
timeout=50
 +
image=/boot/kernel-genkernel-x86_64-3.13.0
 +
initrd=/boot/initramfs-genkernel-x86_64-3.13.0
 +
label=funtoo
 +
</pre>}}
 +
 
 +
== Syslinux bootloader setup ==
 +
Syslinux is another advanced bootloader which you can find on all live CD's. Syslinux bootloader does not require additional BIOS boot partition. /dev/sda2 is the root partition.
 +
<console>
 +
# ##i##emerge syslinux
 +
# ##i##mkdir /boot/extlinux
 +
# ##i##extlinux --install /boot/extlinux
 +
# ##i##dd bs=440 conv=notrunc count=1 if=/usr/share/syslinux/mbr.bin of=/dev/sda
 +
- or -
 +
# ##i##sgdisk /dev/sda --attributes=1:set:2
 +
# ##i##dd bs=440 conv=notrunc count=1 if=/usr/share/syslinux/gptmbr.bin of=/dev/sda, for GPT partition
 +
</console>
 +
 
 +
Example <code>/boot/extlinux/extlinux.conf</code>:
 +
 
 +
{{File
 +
|/boot/extlinux/extlinux.conf|<pre>
 +
LABEL kernel1_bzImage-3.2.1
 +
MENU LABEL Funtoo Linux bzImage-3.2.1
 +
LINUX /bzImage-3.2.1
 +
INITRD /initramfs.cpio.gz
 +
APPEND rootfstype=ext4 luks enc_root=/dev/sda2 lvm root=/dev/mapper/vg-root
 +
</pre>}}
 +
 
 +
= Final steps =
 +
Umount everything, close encrypted drive and reboot
 +
<console>
 +
# ##i##umount -l -v /mnt/funtoo/{dev, proc, home, usr/portage, boot}
 +
# ##i##vgchange -a n
 +
# ##i##cryptsetup luksClose /dev/sda2 dmcrypt_root
 +
</console>
 +
After reboot you will get the following:
 +
<console>
 +
>>> better-initramfs started. Kernel version 2.6.35-gentoo-r10
 +
>>> Create all the symlinks to /bin/busybox.
 +
>>> Initiating /dev/dir
 +
>>> Getting LVM volumes up (if any)
 +
Reding all physical volumes. This make take awhile...
 +
No volume group found
 +
No volume group found
 +
>>> Opening encrypted partition and mapping to /dev/mapper/dmcrypt_root
 +
Enter passphrase fore /dev/sda2:
 +
</console>
 +
Type your password
 +
 
 +
<console>
 +
>>> Again, getting LVM volumes up (if any, after map dmcrypt).
 +
  Reading all physical volumes.  This may take a while...
 +
  Found volume group "vg" using metadata type lvm2
 +
  4 logical volume(s) in volume group "vg" now active
 +
>>> Mounting rootfs to /newroot
 +
>>> Umounting /sys and /proc.
 +
>>> Switching root to /newroot and executing /sbin/init.
 +
INIT: version 2.88 booting
 +
Loading /libexec/rc/console/keymap
 +
  OpenRC 0.6.1 is starting up Funtoo Linux (x86_64)
 +
...boot messages omitted for clarity
 +
 
 +
orion login: oleg
 +
Password:
 +
Last login: Thu Oct 14 20:49:21 EEST 2010 on tty1
 +
oleg@orion ~ %
 +
</console>
 +
 
 +
= Additional links and information =
 +
* [[gentoo-wiki:Root filesystem over LVM2, DM-Crypt and RAID|Root filesystem over LVM2, DM-Crypt, and RAID]]
 +
* [http://wiki.archlinux.org/index.php/System_Encryption_with_LUKS_for_dm-crypt System Encryption with LUKS for dm-crypt]
 +
* [http://en.wikipedia.org/wiki/Logical_volume_management Wikipedia article on LVM]
 +
* [https://wiki.archlinux.org/index.php/Dm-crypt_with_LUKS Arch Wiki article]
 +
 
 +
[[Category:HOWTO]]

Revision as of 13:00, 15 February 2014

This howto describes how to setup LVM and rootfs with cryptoLUKS-encrypted drive. It is not meant to be a standalone installation guide, rather, it is meant to be read alongside the Funtoo Linux Installation Guide.

Contents

Prepare the hard drive and partitions

This is an example partition scheme, you may want to choose differently. /dev/sda1 used as /boot. /dev/sda2 will be encrypted drive with LVM.

  • /dev/sda1 -- /boot partition.
  • /dev/sda2 -- BIOS boot partition (not needed for MBR - only needed if you are using GPT) This step required for GRUB2. For more info, see: [1] for more information on GPT and MBR.
  • /dev/sda3 -- / partition, will be the drive with LUKS and LVM.

Wipe the hard drive

Warning: This action will destroy all data on the disk.
# gdisk /dev/sda

Command: x ↵
Expert command: z ↵
About to wipe out GPT on /dev/sda. Proceed?: y ↵
GPT data structures destroyed! You may now partition the disk using fdisk or other utilities.
Blank out MBR?: y ↵

Note Note: You will get a message about reaching the end of the device when the dd command has finished. This behavior is intended.

Encrypting the drive

Read more about different cipher options here: [2]

# cryptsetup --cipher aes-xts-plain64 luksFormat /dev/sda3
# cryptsetup luksOpen /dev/sda3 dmcrypt_root

There you'll be prompted to enter your password phrase for encrypted drive, type your paranoid password there.

Create logical volumes

# pvcreate /dev/mapper/dmcrypt_root
# vgcreate vg /dev/mapper/dmcrypt_root
# lvcreate -L10G --name root vg           
# lvcreate -L2G --name swap vg
# lvcreate -L5G --name portage vg
# lvcreate -l 100%FREE -nhome vg

Feel free to specify your desired size by altering the numbers after the -L flag. For example, to make your portage dataset 20GB's, use the flag -L20G instead of -L5G.

Create a filesystem on volumes

# mkfs.ext2 /dev/sda1
# mkswap /dev/mapper/vg-swap
# mkfs.ext4 /dev/mapper/vg-root
# mkfs.ext4 /dev/mapper/vg-portage
# mkfs.ext4 /dev/mapper/vg-home

Basic system setup

# swapon /dev/mapper/vg-swap
# mkdir /mnt/funtoo
# mount /dev/mapper/vg-root /mnt/funtoo
# mkdir -p /mnt/funtoo/{boot,usr/portage,home}
# mount /dev/sda1 /mnt/funtoo/boot
# mount /dev/mapper/vg-portage /mnt/funtoo/usr/portage
# mount /dev/mapper/vg-home /mnt/funtoo/home

Now perform all the steps required for basic system install, please follow [3] don't forget to emerge the following before your install is finished:

  • cryptsetup
  • lvm2
  • a bootloader (grub recommended)
  • kernel sources

Editing the fstab

Fire up your favorite text editor to edit /etc/fstab. You want to put the following in the file:

# <fs>                  <mountpoint>  <type>    <opts>                          <dump/pass>
/dev/sda1               /boot         ext2      noauto,noatime                  1 2
/dev/mapper/vg-swap     none          swap      sw                              0 0
/dev/mapper/vg-root     /             ext4      noatime,nodiratime,defaults     0 1
/dev/sr0                /mnt/cdrom    auto      noauto,ro                       0 0
/dev/mapper/vg-portage  /usr/portage  ext4      noatime,nodiratime              0 0
/dev/mapper/vg-home     /home         ext4      noatime,nodiratime              0 0

Kernel options

Note Note: This part is particularly important: pay close attention.








Initramfs setup and configuration

Better-initramfs

Build your initramfs with better-initramfs project.

Note Note: better-initramfs supports neither dynamic modules nor udev, so you should compile your kernel with built-in support for your block devices and file system support.

# cd /opt
# git clone git://github.com/slashbeast/better-initramfs.git
# cd better-initramfs
# less README.rst
# bootstrap/bootstrap-all
# make prepare
# make image

Copy resulting initramfs.cpio.gz to /boot:

# cp output/initramfs.cpio.gz /boot

Alternatively, a pre-compiled binary initramfs is available at https://bitbucket.org/piotrkarbowski/better-initramfs/downloads

# wget https://bitbucket.org/piotrkarbowski/better-initramfs/downloads/release-x86_64-v0.7.2.tar.bz2
# tar xf release-x86_64-v0.5.tar.bz2
# cd release*
# gzip initramfs.cpio
# cp initramfs.cpio.gz /boot

Remember, better-initramfs project is a work in progress, so you need to update from time to time. It can be done easily with git. Go to the better-initramfs source dir and follow:

# cd /opt/better-initramfs
# git pull
# less ChangeLog

Note Note: Please read the ChangeLog carefuly and perform necessary updates to /etc/boot.conf. Also, please backup the working /boot/initramfs.cpio.gz and /etc/boot.conf before updating better-initramfs.

Genkernel

Funtoo's genkernel capable to create initramfs for encrypted drive. Compile and install kernel and initramfs of your favorite kernel sources:

# genkernel --kernel-config=/path/to/your/custom-kernel-config --no-mrproper --makeopts=-j5 --install --lvm --luks all 

Bootloader Configuration

Grub2 configuration

better-initramfs

An example /etc/boot.conf for better-initramfs:

boot {
  generate grub
  default "Funtoo Linux"
  timeout 3
}
"Funtoo Linux" {
  kernel vmlinuz[-v]
  initrd /initramfs.cpio.gz
  params += enc_root=/dev/sda3 lvm luks root=/dev/mapper/vg-root  rootfstype=ext4 resume=swap:/dev/mapper/vg-swap quiet

Now, run boot-update to write the configuration files to /boot/grub/grub.cfg

genkernel

Configure the bootloader as described above, with correct kernel and initramfs images names. An example for genkernel and grub2. You will be editing /etc/boot.conf:

boot {
  generate grub
  default "Funtoo Linux"
  timeout 3
}
"Funtoo Linux" {
  kernel kernel-genkernel-x86_64-3.13.0
  initrd initramfs-genkernel-x86_64-3.13.0
  params += crypt_root=/dev/sda3 dolvm real_root=/dev/mapper/vg-root  rootfstype=ext4 resume=swap:/dev/mapper/vg-swap quiet

Lilo configuration

For oldschool geeks, an example for lilo bootloader. Emerge lilo with device-mapper support

# echo 'sys-boot/lilo device-mapper' >> /etc/portage/package.use/lilo
# emerge lilo

Example /etc/lilo.conf:

append="init=/linuxrc dolvm crypt_root=/dev/sda2 real_root=/dev/mapper/vg-root"
boot=/dev/sda
compact
default=funtoo
lba32
prompt
read-only
timeout=50
image=/boot/kernel-genkernel-x86_64-3.13.0
initrd=/boot/initramfs-genkernel-x86_64-3.13.0
label=funtoo

Syslinux bootloader setup

Syslinux is another advanced bootloader which you can find on all live CD's. Syslinux bootloader does not require additional BIOS boot partition. /dev/sda2 is the root partition.

# emerge syslinux
# mkdir /boot/extlinux
# extlinux --install /boot/extlinux
# dd bs=440 conv=notrunc count=1 if=/usr/share/syslinux/mbr.bin of=/dev/sda
- or -
# sgdisk /dev/sda --attributes=1:set:2
# dd bs=440 conv=notrunc count=1 if=/usr/share/syslinux/gptmbr.bin of=/dev/sda, for GPT partition

Example /boot/extlinux/extlinux.conf:

LABEL kernel1_bzImage-3.2.1
MENU LABEL Funtoo Linux bzImage-3.2.1
LINUX /bzImage-3.2.1
INITRD /initramfs.cpio.gz
APPEND rootfstype=ext4 luks enc_root=/dev/sda2 lvm root=/dev/mapper/vg-root

Final steps

Umount everything, close encrypted drive and reboot

# umount -l -v /mnt/funtoo/{dev, proc, home, usr/portage, boot} 
# vgchange -a n
# cryptsetup luksClose /dev/sda2 dmcrypt_root

After reboot you will get the following:

>>> better-initramfs started. Kernel version 2.6.35-gentoo-r10
>>> Create all the symlinks to /bin/busybox.
>>> Initiating /dev/dir
>>> Getting LVM volumes up (if any)
Reding all physical volumes. This make take awhile...
No volume group found
No volume group found
>>> Opening encrypted partition and mapping to /dev/mapper/dmcrypt_root
Enter passphrase fore /dev/sda2:

Type your password

>>> Again, getting LVM volumes up (if any, after map dmcrypt).
  Reading all physical volumes.  This may take a while...
  Found volume group "vg" using metadata type lvm2
  4 logical volume(s) in volume group "vg" now active
>>> Mounting rootfs to /newroot
>>> Umounting /sys and /proc.
>>> Switching root to /newroot and executing /sbin/init.
INIT: version 2.88 booting
Loading /libexec/rc/console/keymap
  OpenRC 0.6.1 is starting up Funtoo Linux (x86_64)
...boot messages omitted for clarity
   
orion login: oleg
Password:
Last login: Thu Oct 14 20:49:21 EEST 2010 on tty1
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