Setting up disks manually: Difference between revisions

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{{Draft}}
System Disk Mode is the traditional or classic harddisk installation of Alpine Linux. This installation mode is suitable for most use cases including generic [[:Category:Desktop|desktop]], development machines etc.


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.
If an entire hard disk(s) is available for Alpine Linux, [[Installation#setup-alpine_based_System_Disk_Install|setup-alpine based install]] is the recommended way to install Alpine Linux. For all other use cases, follow the [[Alpine_setup_scripts#setup-disk|<code>setup-disk</code>]] based Installation given below.


=== RAID ===
== setup-disk based Installation ==
<code>setup-disk</code> will automatically build a RAID array if you supply the '''-r''' switch, or if you specify more than one device.
 
To perform a traditional hard-disk installation of Alpine Linux with basic to complex partitioning needs, complete the [[Installation#Base_configuration|base configuration]] first. Then [[#Creating_partitions|partition]], [[#Formatting_partitions|format]] and mount your partitions on a MOUNTPOINT {{Path|'''/mnt'''}}. Finally, run the command {{Codeline|'''<Code>setup-disk -m sys /mnt</Code>'''}} to install Alpine Linux with {{Path|'''/mnt'''}} as root.
 
# Follow the [[Installation#General_course_of_action|Installation guide]] to complete the [[Installation#Base_configuration|base configuration]], if not already done.
# If necessary formatted partition(s) are unavailable, manually [[#Creating_partitions|create]] them first and [[#Formatting_partitions|format]] them with appropriate [[Filesystems|filesystem]] tools.
# Mount the '''/ (root)'''  partition on a mount point i.e say {{Path|/mnt}} as follows: {{Cmd|# mount /dev/sdXY /mnt}}
# If you're using EFI, make sure you create a mount point <code>/mnt/boot</code>.  {{Cmd|# mkdir -p /mnt/boot}}
# Find the correct partition name for <code>esp</code> partition and mount it on the above mount point: {{Cmd|# mount /dev/sdXY /mnt/boot}}
# If [[Filesystems#Swap_Partition|swap]] partition is available, you can also enable it now: {{Cmd|# swapon /dev/sdXY }}
# Install Alpine Linux using the following command: {{Cmd|# setup-disk -m sys /mnt}}
# <code>setup-disk</code> will perform a traditional hard disk install of your running system, detects your file system layout and generates {{Path|/etc/fstab}} and installs a [[Bootloaders|bootloader]] based on the <Code>BOOTLOADER</Code> [[Alpine_setup_scripts#Environment_Variables|environment variable]].
# At the end of Installation, you can [[Installation#Reboot|reboot]] to boot into the newly installed Alpine Linux and [[Installation#Post-Installation|configure]] further.
 
== Manual partitioning ==
 
=== Partitioning tools ===
 
The installation image enviroment may have only the very basic busybox built-in <code>fdisk</code> command available. Busybox `fdisk` is rather limited for edit operations.  Instead, alpine allows you to install more complete partitioning tool packages like <code>sfdisk</code> (scriptable fdisk), <code>gptfdisk</code>, <code>parted</code> (CLI), <code>cfdisk</code> (text menus), or even <code>gparted</code> (after [[Installation#Post-Installation|setting up a graphical environment]]).
These tools can be installed even during [[Installation]] immediately after setting up [[Installation#Base_configuration|base configuration]].
 
=== Creating partitions ===
{{Warning|Make sure to choose the correct disk device in the below section. If you choose the wrong device, you will lose your data. Make a backup first and do not proceed, if you are unsure.}}
<code>cfdisk</code> will be used in all examples here as it is based on text menu without any dependencies. However, installing the package {{Pkg|<code>cfdisk</code>}} requires network to be available if using Standard ISO boot image. Alternately, {{Pkg|<code>sfdisk</code>}} is available and can be installed without network.
 
The following step installs the package {{Pkg|<code>cfdisk</code>}}:
{{cmd|# apk add cfdisk }}
 
<code>cfdisk</code> will be used to create partitions. Before using <code>cfdisk</code>, the disk name must be identified by using <code>blkid</code>:
 
{{cmd|# blkid}}
<pre>
/dev/sdX1: LABEL="some" UUID="..." TYPE="vfat"
/dev/sdX2: LABEL="other" UUID="..." TYPE="ext4"
</pre>
 
When <code>cfdisk</code> is run as follows, it looks for existing partitions on the disk {{Path|/dev/sdX}} :
{{cmd|# cfdisk /dev/sdX}}
 
For Alpine Linux, only the '''(/)'''root partition is mandatory to. Even  a '''/boot''' partition and  '''swap''' are optional, when using


If you instead want to build your RAID array manually, see [[Setting up a software raid1 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.
=== Resizing an existing partition ===
{{Warning|Make sure to choose the correct disk device in the below section. If you choose the wrong device, you will lose your data. Make a backup first and do not proceed, if you are unsure.}}


=== Encryption ===
<code>cfdisk</code> and <code>resize2fs</code> can be used to resize existing partitions of ext2/3/4 filsystem on the disk. For other filsystems, the necessary [[Filesystems#Filesystem_Tools|filesystem tools]] must be installed. This can be done while booted.


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.
[[File:Cfdisk screenshot alpine 2024-03-04 143916.png|thumb|cfdisk screenshot ]]


=== LVM ===
To resize disk, launch the <code>cfdisk</code>:
<code>setup-disk</code> will automatically build and use volumes in a LVM group if you supply the '''-L''' switch.
{{cmd|# cfdisk {{path|/dev/sda}}}}


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
# Select the target partition, here as per image {{path|/dev/sda3}}
{{Cmd|umount ...
# Select ''Resize'' from the bottom menu.
vgchange -an}}
# Enter the new ''Size'' at the prompt.
before rebooting.
# Select ''Write'', then ''Quit''


=== Dual-booting ===
If a filesystem is resized with -f (online mode), then the system must be rebooted immediately after the change is made.
See [[Installing Alpine on HDD dualbooting|Install to HDD with dual-boot]]


=== Other needs ===
{{cmd|# resize2fs -f {{path|/dev/sda3}}
* [[Installing Alpine Linux in a chroot]]
&num; reboot}}
* [[Replacing non-Alpine Linux with Alpine remotely]]


=== Formatting partitions ===


<!--
Whenever a partition is [[#Creating_partitions|created]], the partition must be formatted first before using it.  Depending on the filesystem to be used, the necessary [[Filesystems#Filesystem_Tools|formatting tool]] for the filesystem must be installed first. Commonly used formatting tools like <code> mkfs.ext4</code>, <code>mkfs.vfat</code>, <code>mkfs.btrfs</code> are part of file system tools {{pkg|dosfstools|repo=main}}, {{pkg|e2fsprogs|repo=main}}, {{pkg|btrfs-progs|repo=main}} respectively. Install the [[Filesystems#Filesystem_Tools|filesystem tools]] first, if not done already.
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/
-->


{{Warning|The {{Path|/dev/sdXY}} is only an example. Make sure you choose the right partition to format!  If you choose the wrong partition, your will lose your data. Make a backup first and do not proceed, if you are unsure.}}
The following examples show how to use the formatting tools for different filesystems:


<!--
* e2fsprogs for ext4,ext3 and ext2. ext4 is the default filesystem in Alpine Linux.
== Setting up the RAID ==
{{Cmd|# mkfs.ext4 /dev/sdaXY}}
Set up a raid array as described [[Setting up a software raid1 array|here]].
* btrfs-progs for [[btrfs]] filesystem
In this document two raid arrays are configured: md0 for swap (512MB) and md1 for /var.
{{Cmd|# mkfs.btrfs /dev/sdaXY}}
*dosfstools for fat12/fat16/fat32 filesystem
{{Cmd|# mkfs.vfat /dev/sdaXY}}
* f2fs-tools for [[F2FS]] filesystem
{{Cmd|# mkfs.f2fs /dev/sdaXY}}


== Create filesystem ==
== Disk layouts ==
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.
{{Draft|This entire section including RAID, Encryption and LVM needs to be updated.}}
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.
It is possible to have one or more of RAID, encrypted, and/or Logical Volume 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 files in the {{Path|/boot}} partition are configured properly.
mke2fs -j /dev/md1


Your {{Path|/boot}} directory 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}}, then devote the rest of your disk to a separate partition on which you layer one or more of RAID, encryption, and/or Logical Volumes.


Now edit /etc/fstab and add your new partitions. Mine looks like this:
Sometimes {{Path|/boot}} is also set up 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.
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 ==
A typical setup might look like this:
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
<pre>
  mkdir /var
One-disk system
  mount /var
---------------
  mv /var.tmp/* /var
  +------------------------------------------------+
  rmdir /var.tmp
  |  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                | |  |
  |  |  +-------------------------------------+ |  |
  |  +------------------------------------------+ |
  +------------------------------------------------+


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 ==
Two-disk system
Now we have everything up and running. We need to make sure that everything will be restored during next reboot.
---------------
  +------------------------------------------------+  +------------------------------------------------+
  |  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 |
  |                                                |  |                                                |
  +------------------------------------------------+  +------------------------------------------------+


Create an initscript that will mount /var for you during boot. I call it /etc/init.d/mountdisk and it looks like this:
</pre>
#!/sbin/runscript
start() {
        ebegin "Mounting /var"
        mount /var
        eend $?
}
stop() {
        ebegin "Unmounting /var"
        umount /var
        eend $?
}


Make it exectutable:
In a three-disk system, the {{Path|/boot}} would still be RAID1, but the larger partition might, in that case, be RAID5.
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.
=== RAID ===


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
<code>setup-disk</code> will automatically build a RAID array if you supply the '''-r''' switch, or if you specify more than one device.
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.
If you want to build your RAID array manually, see [[Setting up a software RAID array]]. Then you can add additional layers of encryption and/or Logical Volumes, 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.
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.
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 set up 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 set up 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:
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.
{{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
}}


Make sure the links are stored to floppy:
{{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?}}
lbu include /home/*


Also remember to move any newly created users to /var/home and create a link:
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.
adduser bob
mv /home/bob /var/home/
ln -s /var/home/bob /home/bob
lbu include /home/bob


Save to floppy:
=== Encryption ===
lbu commit floppy


== Test it works ==
See [[Setting up encrypted volumes with LUKS]]. You can add an additional Logical Volume layer, 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.
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 ==
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":
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.
-->


{{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.




== Setting up swap ==
If <code>setup-disk</code> sees that you're using LVM, perhaps because you gave it the <code>-L</code> switch, then it will set up your initram and extlinux.conf file properly. However, in other cases, these might not be properly set up. 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:


# create partition with type "linux swap" (82)
{{Cmd|1=&#35; edit $MNT/etc/mkinitfs/mkinitfs.conf to make sure features="..."
# <code>mkswap /dev/sda2</code>
&#35; includes lvm (this field is space-separated and quoted)
# <code>echo -e "/dev/sda2 none swap sw 0 0" >> /mnt/etc/fstab</code>
mkinitfs -c $MNT/etc/mkinitfs/mkinitfs.conf -b $MNT
# <code>swapon /dev/sda2</code> (or <code>rc-service swap start</code>)
&#35; edit $MNT/etc/update-extlinux.conf to make sure root= is set correctly
extlinux --install $MNT/boot --update
}}


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


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.  
You might also need to manually tweak {{Path|$MNT/etc/fstab}}.


{{Todo|Instructions for cryptswap?}}


== see also ==
* [[Installing Alpine on HDD dualbooting|Install to HDD with dual-boot]]
* [[Installing Alpine Linux in a chroot|Installing Alpine Linux in a chroot]]
* [[Replacing non-Alpine Linux with Alpine remotely]]
* [https://github.com/itoffshore/alpine-linux-scripts setup-partitions]
[[Category:Installation]]
[[Category:Installation]]
[[Category:Storage]]
[[Category:Storage]]

Latest revision as of 11:37, 9 November 2024

System Disk Mode is the traditional or classic harddisk installation of Alpine Linux. This installation mode is suitable for most use cases including generic desktop, development machines etc.

If an entire hard disk(s) is available for Alpine Linux, setup-alpine based install is the recommended way to install Alpine Linux. For all other use cases, follow the setup-disk based Installation given below.

setup-disk based Installation

To perform a traditional hard-disk installation of Alpine Linux with basic to complex partitioning needs, complete the base configuration first. Then partition, format and mount your partitions on a MOUNTPOINT /mnt. Finally, run the command setup-disk -m sys /mnt to install Alpine Linux with /mnt as root.

  1. Follow the Installation guide to complete the base configuration, if not already done.
  2. If necessary formatted partition(s) are unavailable, manually create them first and format them with appropriate filesystem tools.
  3. Mount the / (root) partition on a mount point i.e say /mnt as follows:

    # mount /dev/sdXY /mnt

  4. If you're using EFI, make sure you create a mount point /mnt/boot.

    # mkdir -p /mnt/boot

  5. Find the correct partition name for esp partition and mount it on the above mount point:

    # mount /dev/sdXY /mnt/boot

  6. If swap partition is available, you can also enable it now:

    # swapon /dev/sdXY

  7. Install Alpine Linux using the following command:

    # setup-disk -m sys /mnt

  8. setup-disk will perform a traditional hard disk install of your running system, detects your file system layout and generates /etc/fstab and installs a bootloader based on the BOOTLOADER environment variable.
  9. At the end of Installation, you can reboot to boot into the newly installed Alpine Linux and configure further.

Manual partitioning

Partitioning tools

The installation image enviroment may have only the very basic busybox built-in fdisk command available. Busybox `fdisk` is rather limited for edit operations. Instead, alpine allows you to install more complete partitioning tool packages like sfdisk (scriptable fdisk), gptfdisk, parted (CLI), cfdisk (text menus), or even gparted (after setting up a graphical environment). These tools can be installed even during Installation immediately after setting up base configuration.

Creating partitions

Warning: Make sure to choose the correct disk device in the below section. If you choose the wrong device, you will lose your data. Make a backup first and do not proceed, if you are unsure.


cfdisk will be used in all examples here as it is based on text menu without any dependencies. However, installing the package cfdisk requires network to be available if using Standard ISO boot image. Alternately, sfdisk is available and can be installed without network.

The following step installs the package cfdisk:

# apk add cfdisk

cfdisk will be used to create partitions. Before using cfdisk, the disk name must be identified by using blkid:

# blkid

/dev/sdX1: LABEL="some" UUID="..." TYPE="vfat"
/dev/sdX2: LABEL="other" UUID="..." TYPE="ext4"

When cfdisk is run as follows, it looks for existing partitions on the disk /dev/sdX :

# cfdisk /dev/sdX

For Alpine Linux, only the (/)root partition is mandatory to. Even a /boot partition and swap are optional, when using

Resizing an existing partition

Warning: Make sure to choose the correct disk device in the below section. If you choose the wrong device, you will lose your data. Make a backup first and do not proceed, if you are unsure.


cfdisk and resize2fs can be used to resize existing partitions of ext2/3/4 filsystem on the disk. For other filsystems, the necessary filesystem tools must be installed. This can be done while booted.

cfdisk screenshot

To resize disk, launch the cfdisk:

# cfdisk /dev/sda

  1. Select the target partition, here as per image /dev/sda3
  2. Select Resize from the bottom menu.
  3. Enter the new Size at the prompt.
  4. Select Write, then Quit

If a filesystem is resized with -f (online mode), then the system must be rebooted immediately after the change is made.

# resize2fs -f /dev/sda3 # reboot

Formatting partitions

Whenever a partition is created, the partition must be formatted first before using it. Depending on the filesystem to be used, the necessary formatting tool for the filesystem must be installed first. Commonly used formatting tools like mkfs.ext4, mkfs.vfat, mkfs.btrfs are part of file system tools dosfstools, e2fsprogs, btrfs-progs respectively. Install the filesystem tools first, if not done already.

Warning: The /dev/sdXY is only an example. Make sure you choose the right partition to format! If you choose the wrong partition, your will lose your data. Make a backup first and do not proceed, if you are unsure.


The following examples show how to use the formatting tools for different filesystems:

  • e2fsprogs for ext4,ext3 and ext2. ext4 is the default filesystem in Alpine Linux.

# mkfs.ext4 /dev/sdaXY

  • btrfs-progs for btrfs filesystem

# mkfs.btrfs /dev/sdaXY

  • dosfstools for fat12/fat16/fat32 filesystem

# mkfs.vfat /dev/sdaXY

  • f2fs-tools for F2FS filesystem

# mkfs.f2fs /dev/sdaXY

Disk layouts

This material is work-in-progress ...

This entire section including RAID, Encryption and LVM needs to be updated.
(Last edited by Prabuanand on 9 Nov 2024.)

It is possible to have one or more of RAID, encrypted, and/or Logical Volume 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 files in the /boot partition are configured properly.

Your /boot directory 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, then devote the rest of your disk to a separate partition on which you layer one or more of RAID, encryption, and/or Logical Volumes.

Sometimes /boot is also set up 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.

A typical setup 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 want to build your RAID array manually, see Setting up a software RAID array. Then you can add additional layers of encryption and/or Logical Volumes, 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 set up 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 set up 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. You can add an additional Logical Volume layer, 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 set up your initram and extlinux.conf file properly. However, in other cases, these might not be properly set up. 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.


see also

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