Glossary

Image

The node images that Warewulf manages and provisions. Images may be mported from OCI image registries, OCI image archives, Apptainer sandboxes, and manual chroot directories.

Warewulf images are maintained as an uncompressed “virtual node file system” or VNFS, (sometimes also referred to as a “chroot”). These images are then built as images which may then be used to provision a node.

Controller

The Warewulf controller runs the Warewulf daemon (warewulfd) and is responsible for the management, control, and administration of the cluster. This system may also sometimes be referred to as the “master,” “head,” or “admin” node.

A typical Warewulf controller also runs a DHCP service and a TFTP service, and often an NFS service; though these services may be managed separately and on separate servers.

Kernel

In addition to an image, Warewulf also requires a kernel (typically a Linux kernel) in order to provision a node.

Warewulf (after v4.3.0) automatically provisions a kernel detected and extracted from the image itself. In most cases, kernels may be installed in the image using normal system packages, and no special consideration is necessary.

Node

Warewulf nodes are the systems that are being provisioned by Warewulf. The roles of these systems could be “compute”, “storage”, “GPU”, “IO”, etc.

nodes.conf

One of two primary Warewulf configuration files, nodes.conf is a YAML document which records all configuration parameters for Warewulf’s nodes and profiles. It does not contain the images or overlays, but refers to them by name.

Overlay

Warewulf overlays provide customization for the provisioned image. Overlays may be configured on nodes or profiles, as either system or runtime overlays.

System overlays are applied only once, when a node is first provisioned.

Runtime overlays are applied when a node is first provisioned and periodically during the runtime of the node. (The default period is 1 minute.)

Profile

Warewulf profiles are abstract nodes that carry the same configuration attributes but do not provision any specific node. Warewulf nodes may then refer to one or more such profiles for their configuration. In this way, profiles provide a simple mechanism for applying configuration to a group of nodes, and this configuration may be mixed with configuration from other profiles.

wwctl

The main administrative interface for Warewulf is the wwctl command, which provides commands to manage nodes, profiles, images, overlays, kernels, and more.

wwinit

Warewulf performs some setup during the provisioning process before control is passed to the provisioned operating system. This process is referred to as “wwinit,” and is implemented and configured by a script and overlay of the same name.

wwclient

Warewulf adds a wwclient daemon to provisioned nodes. This daemon is responsible for periodically fetching and applying runtime overlays.