Setting up disks manually: Difference between revisions

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You may have complex needs that aren't handled automatically by the [[Alpine Setup Scripts]]. In those cases, you'll need to prepare and mount your disks manually, and then supply the root mountpoint to [[setup-disk]].
{{Draft|Some information on this page may be incomplete or outdate.}}
 
You may have complex needs that aren't handled automatically by the [[Alpine Setup Scripts]]. In those cases, you'll need to prepare your disks manually.
 
It is possible to have one or more of RAID, encryption, and/or LVM on your {{Path|/}} (root) volume. However, the Alpine init script only knows how to handle them when they're layered in that order, and your initram and extlinux.conf file in the {{Path|/boot}} partition are configured properly.
 
Your {{Path|/boot}} cannot reside on an encrypted or LVM volume, at least not with Alpine's default bootloader (extlinux). (Grub2 can deal with {{Path|/boot}} being on an LVM volume.) The usual practice is to create a small partition for {{Path|/boot}}, and then devote the rest of your disk to a separate partition on which you layer one or more of RAID, encryption, and/or LVM.
 
Sometimes {{Path|/boot}} is also setup as a mirrored (RAID1) volume, however this is just for post-init access. That way, when you write a new kernel or bootloader config file to {{Path|/boot}}, it gets written to multiple physical partitions. During the pre-init, bootloader phase, only one of those partitions will be read from.
 
So, typical setups might look like this:
 
<pre>
One-disk system
---------------
  +------------------------------------------------+
  |  small partition (32--100M), holding          |
  |  only /boot, filesystem needn't be journaled  |
  +------------------------------------------------+
  |  rest of disk in second partition              |
  |  +------------------------------------------+  |
  |  | cryptsetup volume                        |  |
  |  |  +-------------------------------------+ |  |
  |  |  |  LVM PV, containing single VG,      | |  |
  |  |  |  containing multiple LVs, holding  | |  |
  |  |  |  /, /home, swap, etc                | |  |
  |  |  +-------------------------------------+ |  |
  |  +------------------------------------------+  |
  +------------------------------------------------+
 
 
Two-disk system
---------------
  +------------------------------------------------+  +------------------------------------------------+
  |  small partition (32--100M), holding          |  |  small partition (32--100M), holding          | These 2 partitions might
  |  only /boot, filesystem needn't be journaled  |  |  only /boot, filesystem needn't be journaled  | form a mirrored (RAID1)
  +------------------------------------------------+  +------------------------------------------------+ volume
  |  rest of disk in second partition              |  |  rest of disk in second partition              |
  | T================================================================================================T | These 2 partitions form
  | T +--------------------------------------------------------------------------------------------+ T | a second mirrored
  | T | cryptsetup volume                                                                          | T | (RAID1) volume
  | T |  +---------------------------------------------------------------------------------------+ | T |
  | T |  | LVM PV, containing single VG,                                                        | | T |
  | T |  | containing multiple LVs, holding                                                      | | T |
  | T |  | /, /home, swap, etc                                                                  | | T |
  | T |  +---------------------------------------------------------------------------------------+ | T |
  | T +--------------------------------------------------------------------------------------------+ T |
  | T================================================================================================T |
  |                                                |  |                                                |
  +------------------------------------------------+  +------------------------------------------------+
 
</pre>
 
In a three-disk system, the {{Path|/boot}} would still be RAID1, but the larger partition might in that case be RAID5.
 
 
=== RAID ===
<code>setup-disk</code> will automatically build a RAID array if you supply the '''-r''' switch, or if you specify more than one device.
 
If you instead want to build your RAID array manually, see [[Setting up a software RAID array]]. Then you can add additional layers of encryption and/or LVM, or just assemble the RAID array, and supply the {{Path|/dev/md<i>i</i>}} device directly to [[setup-disk]]. When you're finished, be sure to disassemble the RAID array before rebooting.
 
If <code>setup-disk</code> sees that you're using RAID---either because you gave it the <code>-r</code> switch, or multiple devices, or a {{Path|/dev/md<i>i</i>}} device---then it will setup your initramfs and extlinux.conf file properly. However, in other cases, such as when you're also using encryption, or you invoke <code>setup-disk</code> with a mounted directory argument, these might not be properly setup for RAID. In that case, you may need to manually edit/rebuild them. The following assumes that <code>$MNT</code> holds the root directory you're installing into:
 
{{Cmd|1=echo "/sbin/mdadm" > $MNT/etc/mkinitfs/files.d/raid
echo "/etc/mdadm.conf" >> $MNT/etc/mkinitfs/files.d/raid
&#35; edit $MNT/etc/mkinitfs/mkinitfs.conf to make sure features="..."
&#35; includes raid (this field is space-separated and quoted)
mkinitfs -c $MNT/etc/mkinitfs/mkinitfs.conf -b $MNT
&#35; edit $MNT/etc/update-extlinux.conf to make sure modules=... contains
&#35; raid1 or raid456 (whichever your / is on; this field is comma-separated)
&#35; also check the root= setting
extlinux --raid --install $MNT/boot --update
}}
 
{{Todo|Does adding the <code>--update</code> option to <code>extlinux ...</code> suffice to make {{Path|/boot/extlinux.conf}} be regenerated? Or do we need to manually tweak that file, or run <code>update-extlinux</code>, as well?}}
 
You might also need to manually tweak {{Path|$MNT/etc/fstab}}. And you might need to copy {{Path|/usr/share/syslinux/mbr.bin}} to your disk's MBR.
 
=== Encryption ===
 
See [[Setting up encrypted volumes with LUKS]]. Then you can add an additional layer of LVM, or just unlock the volume you've created (using <code>cryptsetup luksOpen ...</code>), and supply the {{Path|/dev/mapper/<i>something</i>}} device directly to [[setup-disk]]. When you're finished, be sure to relock the volume (using <code>cryptsetup luksClose ...</code>) before rebooting.
 
If you install your {{Path|/}} (root) on an encrypted volume, you'll need to manually edit/rebuild your initram and your extlinux.conf file. The following assumes that <code>$MNT</code> holds the root directory you're installing into, that you've created the cryptvolume on the device {{Path|/dev/md2}}, and that you want to unlock the encrypted volume into a virtual volume named "crypt":
 
{{Cmd|1=&#35; edit $MNT/etc/mkinitfs/mkinitfs.conf to make sure features="..."
&#35; includes cryptsetup (this field is space-separated and quoted)
mkinitfs -c $MNT/etc/mkinitfs/mkinitfs.conf -b $MNT
&#35; edit $MNT/etc/update-extlinux.conf to make sure default_kernel_opts="..."
&#35; contains cryptroot=/dev/md1 and cryptdm=crypt (this field is also space-separated and quoted)
&#35; also check the root= setting
extlinux --install $MNT/boot --update
}}
 
{{Todo|Does adding the <code>--update</code> option to <code>extlinux ...</code> suffice to make {{Path|/boot/extlinux.conf}} be regenerated? Or do we need to manually tweak that file, or run <code>update-extlinux</code>, as well?}}
 
You might also need to manually tweak {{Path|$MNT/etc/fstab}}.
 
=== LVM ===
<code>setup-disk</code> will automatically build and use volumes in a LVM group if you supply the '''-L''' switch.
 
If you instead want to build your LVM system manually, see [[Setting up Logical Volumes with LVM]]. Then <code>vgchange -ay</code>, format and mount your volumes, and supply the root mountpoint to [[setup-disk]]. When you're finished, be sure to
{{Cmd|umount ...
vgchange -an}}
before rebooting.
 
 
If <code>setup-disk</code> sees that you're using LVM---perhaps because you gave it the <code>-L</code> switch---then it will setup your initram and extlinux.conf file properly. However, in other cases, these might not be properly setup. In that case, you may need to manually edit/rebuild them. The following assumes that <code>$MNT</code> holds the root directory you're installing into:
 
{{Cmd|1=&#35; edit $MNT/etc/mkinitfs/mkinitfs.conf to make sure features="..."
&#35; includes lvm (this field is space-separated and quoted)
mkinitfs -c $MNT/etc/mkinitfs/mkinitfs.conf -b $MNT
&#35; edit $MNT/etc/update-extlinux.conf to make sure root= is set correctly
extlinux --install $MNT/boot --update
}}
 
{{Todo|Does adding the <code>--update</code> option to <code>extlinux ...</code> suffice to make {{Path|/boot/extlinux.conf}} be regenerated? Or do we need to manually tweak that file, or run <code>update-extlinux</code>, as well?}}
 
You might also need to manually tweak {{Path|$MNT/etc/fstab}}.
 
=== Custom partitioning ===
<code>setup-disk</code> will by default set up a root partition, a separate /boot partition and a swap. If you want a different layout you can manually create the partitions, filesystems and mount them up on {{Path|/mnt}} (or any other mount point) and then run:
 
{{Cmd|setup-disk /mnt}}
 
<code>setup-disk</code> will install your running system on the mounted root, detect your file system layout and generate a fstab.
 
If you're going for MBR, you are responsible for making the proper partition bootable and make sure the MBR is OK for extlinux. If you're going for EFI, make sure you set <code>BOOTLOADER=grub</code> and <code>USE_EFI=1</code> and {{Pkg|grub-efi}} and {{Pkg|efibootmgr}} are installed before running <code>setup-disk</code>.
 
See also [https://github.com/itoffshore/alpine-linux-scripts setup-partitions]
 
=== Dual-booting ===
See [[Installing Alpine on HDD dualbooting|Install to HDD with dual-boot]]
 
=== Other needs ===
* [[Installing Alpine Linux in a chroot]]
* [[Replacing non-Alpine Linux with Alpine remotely]]
 
 
<!--
Create partition with with type "Linux" (83).
apk_add e2fsprogs rsync
mkfs.ext3 /dev/hda1
mount -t ext3 /dev/hda1 /mnt
ROOT=/mnt apk_add uclibc busybox apk-tools alpine-baselayout alpine-conf
# Install busybox links
mkdir /mnt/proc && mount --bind /proc /mnt/proc && chroot /mnt /bin/busybox --install -s && umount /mnt/proc
# Copy the apk repository
rsync -ruav /media/cdrom/apks /mnt
mkdir /mnt/etc/apk && echo "APK_PATH=file://apks" > /mnt/etc/apk/apk.conf
# Copy the hd/ext3 initramfs image, kernel and kernel modules
rsync -ruav /media/cdrom/kernel/generic/hd-ext3.gz /media/cdrom/kernel/generic/bzImage /mnt
rsync -ruav /lib/modules/* /mnt/lib/modules/
-->
 
 
<!--
== Setting up the RAID ==
Set up a raid array as described [[Setting up a software RAID1 array|here]].
In this document two raid arrays are configured: md0 for swap (512MB) and md1 for /var.
 
== Create filesystem ==
We need to install the software to create the filesystem ("format" the partition).
apk_add e2fsprogs
 
If you use an Alpine release older than 1.3.8 you will need to manually create a link to /etc/mtab.
ln -fs /proc/mounts /etc/mtab
 
Create the filesystem. The -j option makes it ext'''3'''. Without the -j option it will become non-journaling ext'''2'''. This step might take some time if your partition is big.
mke2fs -j /dev/md1
 
 
Now edit /etc/fstab and add your new partitions. Mine looks like this:
none            /proc          proc    defaults 0 0
none            /sys            sysfs  defaults 0 0
udev            /dev            tmpfs  size=100k 0 0
none            /dev/pts        devpts  defaults 0 0
tmpfs          /dev/shm        tmpfs  defaults 0 0
/dev/cdrom      /media/cdrom    iso9660 ro 0 0
/dev/fd0        /media/floppy  vfat    noauto  0 0
/dev/usba1      /media/usb      vfat    noauto  0 0
none            /proc/bus/usb  usbfs noauto 0 0
 
/dev/md0        swap            swap    defaults 0 0
/dev/md1        /var            ext3    defaults 0 0
 
== Move the data ==
Now you should stop all services running that put anything in /var (syslog for example). If you have booted on a clean installation and not run setup-alpine, then no services should be running. However, some packages might have created dirs in /var so we need to backup /var mount the new and move all backed up dirs back to the raided /var.
 
mv /var /var.tmp
mkdir /var
mount /var
mv /var.tmp/* /var
rmdir /var.tmp
 
Verify that everyting looks ok with the ''df'' utility.
~ $ df
Filesystem          1k-blocks      Used Available Use% Mounted on
none                    255172    23544    231628  9% /
udev                      100        0      100  0% /dev
/dev/cdrom              142276    142276        0 100% /media/cdrom
/dev/md1              37977060    181056  35866876  1% /var
 
== Survive reboots ==
Now we have everything up and running. We need to make sure that everything will be restored during next reboot.
 
Create an initscript that will mount /var for you during boot. I call it /etc/init.d/mountdisk and it looks like this:
#!/sbin/runscript
start() {
        ebegin "Mounting /var"
        mount /var
        eend $?
}
stop() {
        ebegin "Unmounting /var"
        umount /var
        eend $?
}
 
Make it exectutable:
chmod +x /etc/init.d/mountdisk
 
'''NOTE:''' Since Alpine-1.7.3 there is a ''localmount'' script shipped so you will not need to create your own ''mountdisk'' script.
 
And that /var is mounted *after* raid is created. The -k option will make alpine to unmount the /Var partition during boot. Also add start of swap too boot
rc_add -k -s 06 mountdisk
rc_add -k -s 06 swap
 
The /dev/md* device nodes will not be created automatically so we need to put the on floppy too.
lbu include /dev/md*
 
If you have users on the server and want /home to be permanent, you can create a directory /var/home and create links to /var/home.
mkdir /var/home
mv /home/* /var/home/
ln -s /var/home/* /home/
 
'''NOTE:''' You cannot just replace /home with a link that points to /var/home since the base has a /home directory. When the boot tries to copy the config from floppy it will fail because of the already existing /home directory.
 
Make sure the links are stored to floppy:
lbu include /home/*
 
Also remember to move any newly created users to /var/home and create a link:
adduser bob
mv /home/bob /var/home/
ln -s /var/home/bob /home/bob
lbu include /home/bob
 
Save to floppy:
lbu commit floppy
 
== Test it works ==
Reboot computer. Now should the raid start and /var should be mounted. Check with df:
~ $ df
Filesystem          1k-blocks      Used Available Use% Mounted on
none                    255172    23976    231196  9% /
mdev                      100        0      100  0% /dev
/dev/cdrom              140932    140932        0 100% /media/cdrom
/dev/md1              37977060    180984  35866948  1% /var
 
== Upgrades ==
Since the package database is placed on disk, you cannot update by simply replacing the CDROM. You will have to either run the upgrade on the new CDROM or run ''apk_add -u ... && update-conf'' manually.
-->


== Setting up swap ==
== Setting up swap ==


# create partition with type "linux swap" (82)
# create partition with type "linux swap" (82) (If you're going to use an LVM logical volume for swap, skip this step and <code>lvcreate</code> that instead.)
# <code>mkswap /dev/sda2</code>
# <code>mkswap /dev/sda2</code>
# <code>echo -e "/dev/sda2 none swap sw 0 0" >> /mnt/etc/fstab</code>
# <code>echo -e "/dev/sda2 none swap sw 0 0" >> /mnt/etc/fstab</code>
# <code>swapon /dev/sda2</code>
# <code>swapon /dev/sda2</code> (or <code>rc-service swap start</code>)
 
Then {{Cmd|free -m}} will show how much swap space is available (in MB).
 
If you prefer maximum speed, you don't need configure any raid devices for swap. Just add 2 swap partitions on different disks and linux will stripe them automatically. The downside is that at the moment one disk fails, the system will go down. For better reliability, put swap on RAID1.


Then {{Cmd|free}} will show how much swap space is available.
{{Todo|Instructions for cryptswap?}}


If you prefer maximum speed, you don't need configure any raid devices for swap. Just add 2 swap partitions on different disks and linux will stripe them automatically. The downside is that at the moment one disk fails, the system will go down. For better reliability, put swap on raid1.  
= =
* [https://beta.docs.alpinelinux.org/user-handbook/0.1a/Installing/manual.html#_finalizing beta.docs.alpinelinux.org] ''([http://archive.md/2KQPQ archive])''


See also [[Alpine Setup Scripts#setup-cryptswap|setup-cryptswap]].
[[Category:Installation]]
[[Category:Storage]]

Revision as of 19:30, 9 February 2020

This material is work-in-progress ...

Some information on this page may be incomplete or outdate.
(Last edited by PureTryOut on 9 Feb 2020.)

You may have complex needs that aren't handled automatically by the Alpine Setup Scripts. In those cases, you'll need to prepare your disks manually.

It is possible to have one or more of RAID, encryption, and/or LVM on your / (root) volume. However, the Alpine init script only knows how to handle them when they're layered in that order, and your initram and extlinux.conf file in the /boot partition are configured properly.

Your /boot cannot reside on an encrypted or LVM volume, at least not with Alpine's default bootloader (extlinux). (Grub2 can deal with /boot being on an LVM volume.) The usual practice is to create a small partition for /boot, and then devote the rest of your disk to a separate partition on which you layer one or more of RAID, encryption, and/or LVM.

Sometimes /boot is also setup as a mirrored (RAID1) volume, however this is just for post-init access. That way, when you write a new kernel or bootloader config file to /boot, it gets written to multiple physical partitions. During the pre-init, bootloader phase, only one of those partitions will be read from.

So, typical setups might look like this: 

One-disk system
---------------
  +------------------------------------------------+
  |  small partition (32--100M), holding           |
  |  only /boot, filesystem needn't be journaled   |
  +------------------------------------------------+
  |  rest of disk in second partition              |
  |  +------------------------------------------+  |
  |  | cryptsetup volume                        |  |
  |  |  +-------------------------------------+ |  |
  |  |  |  LVM PV, containing single VG,      | |  |
  |  |  |  containing multiple LVs, holding   | |  |
  |  |  |  /, /home, swap, etc                | |  |
  |  |  +-------------------------------------+ |  |
  |  +------------------------------------------+  |
  +------------------------------------------------+


Two-disk system
---------------
  +------------------------------------------------+  +------------------------------------------------+
  |  small partition (32--100M), holding           |  |  small partition (32--100M), holding           | These 2 partitions might
  |  only /boot, filesystem needn't be journaled   |  |  only /boot, filesystem needn't be journaled   | form a mirrored (RAID1)
  +------------------------------------------------+  +------------------------------------------------+ volume
  |  rest of disk in second partition              |  |  rest of disk in second partition              |
  | T================================================================================================T | These 2 partitions form
  | T +--------------------------------------------------------------------------------------------+ T | a second mirrored
  | T | cryptsetup volume                                                                          | T | (RAID1) volume
  | T |  +---------------------------------------------------------------------------------------+ | T |
  | T |  | LVM PV, containing single VG,                                                         | | T |
  | T |  | containing multiple LVs, holding                                                      | | T |
  | T |  | /, /home, swap, etc                                                                   | | T |
  | T |  +---------------------------------------------------------------------------------------+ | T |
  | T +--------------------------------------------------------------------------------------------+ T |
  | T================================================================================================T |
  |                                                |  |                                                |
  +------------------------------------------------+  +------------------------------------------------+

In a three-disk system, the /boot would still be RAID1, but the larger partition might in that case be RAID5.


RAID

setup-disk will automatically build a RAID array if you supply the -r switch, or if you specify more than one device.

If you instead want to build your RAID array manually, see Setting up a software RAID array. Then you can add additional layers of encryption and/or LVM, or just assemble the RAID array, and supply the /dev/mdi device directly to setup-disk. When you're finished, be sure to disassemble the RAID array before rebooting.

If setup-disk sees that you're using RAID---either because you gave it the -r switch, or multiple devices, or a /dev/mdi device---then it will setup your initramfs and extlinux.conf file properly. However, in other cases, such as when you're also using encryption, or you invoke setup-disk with a mounted directory argument, these might not be properly setup for RAID. In that case, you may need to manually edit/rebuild them. The following assumes that $MNT holds the root directory you're installing into:

echo "/sbin/mdadm" > $MNT/etc/mkinitfs/files.d/raid echo "/etc/mdadm.conf" >> $MNT/etc/mkinitfs/files.d/raid # edit $MNT/etc/mkinitfs/mkinitfs.conf to make sure features="..." # includes raid (this field is space-separated and quoted) mkinitfs -c $MNT/etc/mkinitfs/mkinitfs.conf -b $MNT # edit $MNT/etc/update-extlinux.conf to make sure modules=... contains # raid1 or raid456 (whichever your / is on; this field is comma-separated) # also check the root= setting extlinux --raid --install $MNT/boot --update

Todo: Does adding the --update option to extlinux ... suffice to make /boot/extlinux.conf be regenerated? Or do we need to manually tweak that file, or run update-extlinux, as well?


You might also need to manually tweak $MNT/etc/fstab. And you might need to copy /usr/share/syslinux/mbr.bin to your disk's MBR.

Encryption

See Setting up encrypted volumes with LUKS. Then you can add an additional layer of LVM, or just unlock the volume you've created (using cryptsetup luksOpen ...), and supply the /dev/mapper/something device directly to setup-disk. When you're finished, be sure to relock the volume (using cryptsetup luksClose ...) before rebooting.

If you install your / (root) on an encrypted volume, you'll need to manually edit/rebuild your initram and your extlinux.conf file. The following assumes that $MNT holds the root directory you're installing into, that you've created the cryptvolume on the device /dev/md2, and that you want to unlock the encrypted volume into a virtual volume named "crypt":

# edit $MNT/etc/mkinitfs/mkinitfs.conf to make sure features="..." # includes cryptsetup (this field is space-separated and quoted) mkinitfs -c $MNT/etc/mkinitfs/mkinitfs.conf -b $MNT # edit $MNT/etc/update-extlinux.conf to make sure default_kernel_opts="..." # contains cryptroot=/dev/md1 and cryptdm=crypt (this field is also space-separated and quoted) # also check the root= setting extlinux --install $MNT/boot --update

Todo: Does adding the --update option to extlinux ... suffice to make /boot/extlinux.conf be regenerated? Or do we need to manually tweak that file, or run update-extlinux, as well?


You might also need to manually tweak $MNT/etc/fstab.

LVM

setup-disk will automatically build and use volumes in a LVM group if you supply the -L switch.

If you instead want to build your LVM system manually, see Setting up Logical Volumes with LVM. Then vgchange -ay, format and mount your volumes, and supply the root mountpoint to setup-disk. When you're finished, be sure to

umount ... vgchange -an

before rebooting.


If setup-disk sees that you're using LVM---perhaps because you gave it the -L switch---then it will setup your initram and extlinux.conf file properly. However, in other cases, these might not be properly setup. In that case, you may need to manually edit/rebuild them. The following assumes that $MNT holds the root directory you're installing into:

# edit $MNT/etc/mkinitfs/mkinitfs.conf to make sure features="..." # includes lvm (this field is space-separated and quoted) mkinitfs -c $MNT/etc/mkinitfs/mkinitfs.conf -b $MNT # edit $MNT/etc/update-extlinux.conf to make sure root= is set correctly extlinux --install $MNT/boot --update

Todo: Does adding the --update option to extlinux ... suffice to make /boot/extlinux.conf be regenerated? Or do we need to manually tweak that file, or run update-extlinux, as well?


You might also need to manually tweak $MNT/etc/fstab.

Custom partitioning

setup-disk will by default set up a root partition, a separate /boot partition and a swap. If you want a different layout you can manually create the partitions, filesystems and mount them up on /mnt (or any other mount point) and then run:

setup-disk /mnt

setup-disk will install your running system on the mounted root, detect your file system layout and generate a fstab.

If you're going for MBR, you are responsible for making the proper partition bootable and make sure the MBR is OK for extlinux. If you're going for EFI, make sure you set BOOTLOADER=grub and USE_EFI=1 and grub-efi and efibootmgr are installed before running setup-disk.

See also setup-partitions

Dual-booting

See Install to HDD with dual-boot

Other needs



Setting up swap

  1. create partition with type "linux swap" (82) (If you're going to use an LVM logical volume for swap, skip this step and lvcreate that instead.)
  2. mkswap /dev/sda2
  3. echo -e "/dev/sda2 none swap sw 0 0" >> /mnt/etc/fstab
  4. swapon /dev/sda2 (or rc-service swap start)

Then

free -m

will show how much swap space is available (in MB).

If you prefer maximum speed, you don't need configure any raid devices for swap. Just add 2 swap partitions on different disks and linux will stripe them automatically. The downside is that at the moment one disk fails, the system will go down. For better reliability, put swap on RAID1.

Todo: Instructions for cryptswap?


Retrieved from "https://wiki.alpinelinux.org/w/index.php?title=Setting_up_disks_manually&oldid=16868"