Disk Management

Warewulf itself does not manage disks, partitions, or file systems directly, but provides structures in the configuration for these objects. At the moment warewulf supports ignition to create the partitions and file systems.


It is not currently possible to manage the root file system with Warewulf.

Warewulf can be used, for example, to create swap partitions or /scratch file systems.

Storage objects

The format of the storage objects is inspired by butane/ignition; but, where butane/ignition uses lists for holding disks, partitions and file systems, Warewulf uses maps instead.

A node or profile can have several disks, where each disk is identified by the path to its block device. Every disks holds a map to its partitions and a bool switch to indicate if an existing partition table should be overwritten if it does not matched the desired configuration.

Each partition is identified by its label. The partition number can be omitted, but specifying it is recommended as ignition may fail without it. Partition sizes should also be set (specified in MiB), except of the last partition: if no size is given, the maximum available size is used. Each partition has the switches should_exist and wipe_partition_entry which control the partition creation process.

File systems are identified by their underlying block device, preferably using the /dev/by-partlabel format. Except for a swap partition, an absolute path for the mount point must be specified for each file system. Depending on the container used, valid formats are btrfs, ext3, ext4, and xfs. Each file system has the switch wipe_filesystem to control whether an existing file system is wiped.

Ignition Implementation

The ignition implementation uses systemd services, as the underlying sgdisk command relies on dbus notifications. All necessary services are distributed by the wwinit overlay and depends on the existence of the file /warewulf/ignition.json. This file is created by the template function {{ createIgnitionJson }} only if the configuration contains necessary specifications for disks, partitions, and file systems. If the file /warewulf/ignition.json exists, the service ignition-disks-ww4.service calls the ignition binary which takes creates partitions and file systems. A systemd .mount unit is created for each configured file system, which also creates the necessary mount points in the root file system. These mount units are required by the enabled ww4-disks.target. Entries in /etc/fstab are created with the no_auto option so that file systems can be easily mounted.


The following command will create a /scratch file system on the node n01

wwctl node set n01 \
  --diskname /dev/vda --diskwipe \
  --partname scratch --partcreate \
  --fsname scratch --fsformat btrfs --fspath /scratch --fswipe

As this is a single file system, the partition number can be omitted.

A swap partition with 1Gig can be added with

wwctl node set n01 \
  --diskname /dev/vda \
  --partname swap --partsize=1024 --partnumber 1 \
  --fsname swap --fsformat swap --fspath swap

which has the partition number 1 so that it will be added before the /scratch partition.