Custom Disk Volumes

KIWI NG supports defining custom volumes by using the logical volume manager (LVM) for the Linux kernel or by setting volumes at filesystem level when filesystem supports it (e.g. btrfs).

Volumes are defined in the KIWI NG description file config.xml, using systemdisk. This element is a child of the type. Volumes themselves are added via (multiple) volume child elements of the systemdisk element:

<image schemaversion="8.0" name="openSUSE-Leap-15.1">
  <type image="oem" filesystem="btrfs">
    <systemdisk name="vgroup" preferlvm="true">
      <volume name="usr/lib" size="1G" label="library"/>
      <volume name="@root" freespace="500M"/>
      <volume name="etc_volume" mountpoint="etc" copy_on_write="false"/>
      <volume name="bin_volume" size="all" mountpoint="/usr/bin" quota="2G"/>
    </systemdisk>
  </type>
</image>

Additional non-root volumes are created for each volume element. Volume details can be defined by setting the following volume attributes:

name: Required attribute representing the volume’s name. Additionally, this attribute is interpreted as the mountpoint if the mountpoint attribute is not used.
mountpoint: Optional attribute that specifies the mountpoint of this volume.
size: Optional attribute to set the size of the volume. If no suffix (M or G) is used, then the value is considered to be in megabytes.
Note

Special name for the root volume

One can use the @root name to refer to the volume mounted at /, in case some specific size attributes for the root volume have to be defined. For instance:
```
<volume name="@root" size="4G"/>
```
In addition to the custom size of the root volume it’s also possible to setup the name of the root volume as follows:
```
<volume name="@root=rootlv" size="4G"/>
```
If no name for the root volume is specified the default name: LVRoot applies.
freespace: Optional attribute defining the additional free space added to the volume. If no suffix (M or G) is used, the value is considered to be in megabytes.
label: Optional attribute to set filesystem label of the volume.
copy_on_write: Optional attribute to set the filesystem copy-on-write attribute for this volume.
quota: Optional attribute for the btrfs filesystem only. Allows to specify a quota size for the generated volume.
filesystem_check: Optional attribute to indicate that this filesystem should perform the validation to become filesystem checked. The actual constraints if the check is performed or not depends on systemd and filesystem specific components. If not set or set to false no system component will be triggered to run an eventual filesystem check, which results in this filesystem to be never checked. The latter is the default.
arch: Optional attribute to create the volume only if it matches the specified host architecture. Multiple architecture names can be specified as comma separated list.

Warning

The size attributes for filesystem volumes, as for btrfs, are ignored and have no effect.

The systemdisk element additionally supports the following optional attributes:

name: The volume group name, by default kiwiVG is used. This setting is only relevant for LVM volumes.
preferlvm: Boolean value instructing KIWI NG to prefer LVM even if the used filesystem has its own volume management system.