Root on ZFS with native encryption: Difference between revisions
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This is a guide for installing Alpine Linux with its root partition on an encrypted ZFS volume, using ZFS's own encryption capabilities. The system will be encrypted when powered off and will need to be unlocked by typing a passphrase at boot. To be able to boot the system, the `/boot` partition remains unencrypted. | |||
= | = OpenZFS Guide = | ||
Download the '''extended''' release from https://www.alpinelinux.org/downloads/ as only it contains the zfs kernel | A guide on OpenZFS website supports native encryption, UEFI boot and legacy boot, and multi-disk. See [https://openzfs.github.io/openzfs-docs/Getting%20Started/Alpine%20Linux/Root%20on%20ZFS.html here]. | ||
= Downloading Alpine = | |||
Download the '''extended''' release from https://www.alpinelinux.org/downloads/ as only it contains the zfs kernel modules at the time of writing (2022-02-12). | |||
Write it to a USB device and boot from it. | Write it to a USB device and boot from it. | ||
= Initial Setup = | |||
Run the following | Run the following to start the installation procedure: | ||
{{cmd|setup-alpine}} | |||
Answer all the questions, and hit | Answer all the questions, and hit {{Key|Ctrl}}+{{Key|C}} when prompted for which disk you'd like to use. | ||
== | == Optional: SSH access == | ||
This section is optional and it assumes internet connectivity. You may enable sshd so you can ssh into the box and copy and paste the rest of the commands into | This section is optional and it assumes internet connectivity. You may enable sshd so you can ssh into the box and copy and paste the rest of the commands from these instructions into a terminal window. | ||
Edit | Edit {{path|/etc/ssh/sshd_config}} and search for `Permit`. Change the value after `PermitRootLogin` to read `yes` | ||
save and exit to shell. Run | save and exit to shell. Run {{codeline|service sshd restart}} | ||
Now you can ssh in as root. Do not forget to go back and comment this line out when you're done since it will be enabled on | Now you can ssh in as root. Do not forget to go back and comment this line out when you're done since it will be enabled on the resulting machine. You will be reminded again at the end of this doc. | ||
= Add required packages = | |||
{{cmd|apk add {{pkg|zfs}} {{pkg|sfdisk}} {{pkg|e2fsprogs}} {{pkg|syslinux}}}} | |||
= | = Partition setup = | ||
We're assuming | We're assuming that {{path|/dev/sda}} is the target storage device here and in the rest of the document, but the name of the storage device you wish to install to may be different. To see a list of storage devices and determine the correct one, type {{codeline|sfdisk -l}}. | ||
{{cmd|echo -e "/dev/sda1: start{{=}}1M,size{{=}}100M,bootable\n/dev/sda2: start{{=}}101M" | sfdisk --quiet --label dos /dev/sda}} | |||
== Create device nodes == | == Create device nodes == | ||
{{cmd|mdev -s}} | |||
== Create the /boot filesystem == | == Create the {{path|/boot}} filesystem == | ||
{{cmd|mkfs.ext4 /dev/sda1}} | |||
== Create the root | = ZFS setup = | ||
== Create the root zpool == | |||
{{cmd|modprobe zfs | |||
zpool create -f -o ashift{{=}}12 \ | |||
-O acltype{{=}}posixacl -O canmount{{=}}off -O compression{{=}}lz4 \ | |||
-O dnodesize{{=}}auto -O normalization{{=}}formD -O relatime{{=}}on -O xattr{{=}}sa \ | |||
-O encryption{{=}}aes-256-gcm -O keylocation{{=}}prompt -O keyformat{{=}}passphrase \ | |||
-O mountpoint{{=}}/ -R /mnt \ | |||
rpool /dev/sda2}} | |||
You will have to enter your passphrase at this point. Choose wisely, as your passphrase is most likely [https://gitlab.com/cryptsetup/cryptsetup/wikis/FrequentlyAskedQuestions#5-security-aspects the weakest link in this setup]. | You will have to enter your passphrase at this point. Choose wisely, as your passphrase is most likely [https://gitlab.com/cryptsetup/cryptsetup/wikis/FrequentlyAskedQuestions#5-security-aspects the weakest link in this setup]. | ||
A few notes on the options supplied to zpool: | A few notes on the options supplied to zpool: | ||
<ul> | |||
<li>{{codeline|ashift{{=}}12}} is recommended here because many drives today have 4KiB (or larger) physical sectors, even though they present 512B logical sectors</li> | |||
<li>{{codeline|acltype{{=}}posixacl}} enables POSIX ACLs globally</li> | |||
<li>{{codeline|normalization{{=}}formD}} eliminates some corner cases relating to UTF-8 filename normalization. It also enables `utf8only=on`, meaning that only files with valid UTF-8 filenames will be accepted.</li> | |||
<li>{{codeline|xattr{{=}}sa}} vastly improves the performance of extended attributes, but is Linux-only. If you care about using this pool on other OpenZFS implementation don't specify this option.</li></ul> | |||
After completing this, confirm that the pool has been created: | After completing this, confirm that the pool has been created: | ||
{{cmd|# zpool status}} | |||
Should return something like: | Should return something like: | ||
| Line 75: | Line 77: | ||
scan: none requested | scan: none requested | ||
config: | config: | ||
NAME STATE READ WRITE CKSUM | NAME STATE READ WRITE CKSUM | ||
rpool ONLINE 0 0 0 | rpool ONLINE 0 0 0 | ||
sda2 ONLINE 0 0 0 | sda2 ONLINE 0 0 0 | ||
errors: No known data errors | errors: No known data errors | ||
== Create the required datasets and mount root == | == Create the required datasets and mount root == | ||
{{cmd|zfs create -o mountpoint{{=}}none -o canmount{{=}}off rpool/ROOT | |||
zfs create -o mountpoint{{=}}legacy rpool/ROOT/alpine | |||
mount -t zfs rpool/ROOT/alpine /mnt/}} | |||
== Mount the {{path|/boot}} filesystem == | |||
{{cmd|mkdir /mnt/boot/ | |||
mount -t ext4 /dev/sda1 /mnt/boot/}} | |||
== Enable ZFS' services == | |||
{{cmd|rc-update add zfs-import sysinit | |||
rc-update add zfs-mount sysinit}} | |||
= Install Alpine Linux = | |||
{{cmd|setup-disk /mnt | |||
dd if{{=}}/usr/share/syslinux/mbr.bin of{{=}}/dev/sda # write mbr so we can boot}} | |||
= Reboot and enjoy! = | |||
😉 | 😉 | ||
Latest revision as of 17:18, 21 August 2023
This is a guide for installing Alpine Linux with its root partition on an encrypted ZFS volume, using ZFS's own encryption capabilities. The system will be encrypted when powered off and will need to be unlocked by typing a passphrase at boot. To be able to boot the system, the `/boot` partition remains unencrypted.
OpenZFS Guide
A guide on OpenZFS website supports native encryption, UEFI boot and legacy boot, and multi-disk. See here.
Downloading Alpine
Download the extended release from https://www.alpinelinux.org/downloads/ as only it contains the zfs kernel modules at the time of writing (2022-02-12).
Write it to a USB device and boot from it.
Initial Setup
Run the following to start the installation procedure:
setup-alpine
Answer all the questions, and hit Ctrl+C when prompted for which disk you'd like to use.
Optional: SSH access
This section is optional and it assumes internet connectivity. You may enable sshd so you can ssh into the box and copy and paste the rest of the commands from these instructions into a terminal window.
Edit /etc/ssh/sshd_config and search for `Permit`. Change the value after `PermitRootLogin` to read `yes`
save and exit to shell. Run service sshd restart
Now you can ssh in as root. Do not forget to go back and comment this line out when you're done since it will be enabled on the resulting machine. You will be reminded again at the end of this doc.
Add required packages
apk add zfs sfdisk e2fsprogs syslinux
Partition setup
We're assuming that /dev/sda is the target storage device here and in the rest of the document, but the name of the storage device you wish to install to may be different. To see a list of storage devices and determine the correct one, type sfdisk -l.
echo -e "/dev/sda1: start=1M,size=100M,bootable\n/dev/sda2: start=101M" | sfdisk --quiet --label dos /dev/sda
Create device nodes
mdev -s
Create the /boot filesystem
mkfs.ext4 /dev/sda1
ZFS setup
Create the root zpool
modprobe zfs zpool create -f -o ashift=12 \ -O acltype=posixacl -O canmount=off -O compression=lz4 \ -O dnodesize=auto -O normalization=formD -O relatime=on -O xattr=sa \ -O encryption=aes-256-gcm -O keylocation=prompt -O keyformat=passphrase \ -O mountpoint=/ -R /mnt \ rpool /dev/sda2
You will have to enter your passphrase at this point. Choose wisely, as your passphrase is most likely the weakest link in this setup.
A few notes on the options supplied to zpool:
- ashift=12 is recommended here because many drives today have 4KiB (or larger) physical sectors, even though they present 512B logical sectors
- acltype=posixacl enables POSIX ACLs globally
- normalization=formD eliminates some corner cases relating to UTF-8 filename normalization. It also enables `utf8only=on`, meaning that only files with valid UTF-8 filenames will be accepted.
- xattr=sa vastly improves the performance of extended attributes, but is Linux-only. If you care about using this pool on other OpenZFS implementation don't specify this option.
After completing this, confirm that the pool has been created:
# zpool status
Should return something like:
pool: rpool
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
rpool ONLINE 0 0 0
sda2 ONLINE 0 0 0
errors: No known data errors
Create the required datasets and mount root
zfs create -o mountpoint=none -o canmount=off rpool/ROOT zfs create -o mountpoint=legacy rpool/ROOT/alpine mount -t zfs rpool/ROOT/alpine /mnt/
Mount the /boot filesystem
mkdir /mnt/boot/ mount -t ext4 /dev/sda1 /mnt/boot/
Enable ZFS' services
rc-update add zfs-import sysinit rc-update add zfs-mount sysinit
Install Alpine Linux
setup-disk /mnt dd if=/usr/share/syslinux/mbr.bin of=/dev/sda # write mbr so we can boot
Reboot and enjoy!
😉
NOTE: If you went with the optional step, be sure to disable root login after you reboot.