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Distinguish between OS images and overlay images in documentation

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Signed-off-by: Jonathon Anderson <janderson@ciq.com>
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Jonathon Anderson
2026-03-18 08:10:49 -06:00
parent 1fd8b65ebf
commit 7909598a3d
20 changed files with 89 additions and 87 deletions
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6
userdocs/getting-started/el-quickstart.rst
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@@ -155,10 +155,10 @@ configure --all``.
you may need to run ``restorecon -Rv /var/lib/tftpboot/`` to label
files written to ``tftpboot``.
Add a base node image
=====================
Add an OS image
===============
This will pull a basic node image from Docker Hub
This will pull a basic OS image from Docker Hub
and set it for the "default" node profile.
.. code-block:: bash

25
userdocs/getting-started/glossary.rst
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@@ -12,13 +12,7 @@ External services
configures a DHCP server (either ISC DHCP or dnsmasq) and a TFTP server.
Image
The node images that Warewulf manages and provisions. Images may be imported
from OCI image registries, OCI image archives, Apptainer sandboxes, and
manual chroot directories.
Warewulf images are maintained as an uncompressed "virtual node file system"
(VNFS, sometimes also referred to as a "chroot"). These virtual file systems
are then built as single-file images which may be used to provision a node.
See "Operating System (OS) Image" or "Overlay Image."
Kernel
In addition to an image, Warewulf also requires a kernel (typically a Linux
@@ -42,6 +36,14 @@ nodes.conf
This file is sometimes referred to as the "nodes database" or "node
registry."
Operating System (OS) Image
An operating system image (or OS image) contains a bootable operating
system. When provisioning a cluster node, Warewulf combines the OS image
with the node's overlay images to provision the complete, configured image.
OS images may be imported from OCI image registries, OCI image archives,
Apptainer sandboxes, and manual chroot directories.
Overlay
Warewulf overlays provide customization for the provisioned image. Overlays
may be configured on nodes or profiles, as either **system** or **runtime**
@@ -56,6 +58,15 @@ Overlay
Warewulf includes a number of **distribution overlays**; but additional
**site overlays** can be added to a Warewulf environment.
Overlay Image
An overlay image contains the rendered contents of multiple overlays for a
given cluster node. Nodes have a "system overlay" image and a "runtime
overlay" image, based on the system and runtime overlays associated with each
node.
Overlay images are not managed directly, but are built by the ``wwctl
overlay build`` command.
Profile
Warewulf profiles are abstract nodes that carry the same configuration
attributes but do not provision any specific node. Warewulf nodes may then

16
userdocs/getting-started/introduction.rst
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@@ -9,10 +9,10 @@ Warewulf is known for its massive scalability and simple management of stateless
(disk optional) provisioning.
Warewulf leverages a simple administrative model centralizing administration
around virtual node images which are used to provision out to the cluster nodes.
This means you can have hundreds or thousands of cluster nodes all booting and
running on the same node image. As of Warewulf v4, the node image can be managed
using industry-standard container tooling and/or CI/CD pipelines. This can be as
around virtual OS images which are used to provision cluster nodes. This means
you can have hundreds or thousands of cluster nodes all booting and running on
the same OS image. As of Warewulf v4, the OS image can be managed using
industry-standard container tooling and/or CI/CD pipelines. This can be as
simple as DockerHub or your own private GitLab CI infrastructure. With this
architecture, Warewulf combines the best of High Performance Computing (HPC),
Cloud, Hyperscale, and Enterprise deployment principles to create and maintain
@@ -47,7 +47,7 @@ flexible provisioning system for all types of clusters.
any environment.
* **Secure**: Warewulf supports SELinux out-of-the-box. Just install SELinux in
your node image and let Warewulf do the rest!
your OS image and let Warewulf do the rest!
* **Open Source**: Warewulf is and has always been open source. It can be used
in any environment, whether public, private, non-profit, or commercial. And
@@ -70,14 +70,14 @@ configuration and image and overlay assignments.
**Node profiles** provide a flexible abstraction for applying configuration to
multiple nodes.
**Node images** provide a bootable operating system image, including the kernel
that will be used to boot the cluster node. Node images provide a base operating
**Operating system images** provide a bootable image, including the kernel
that will be used to boot the cluster node. OS images provide the base operating
system and, by default, run entirely in memory. This means that when you
reboot the node, the node retains no information about Warewulf or how it
booted; but it also means that they return to their initial known-good state.
**Overlays** customize the provisioned operating system image with static files
and dynamic templates applied with the node image and, optionally, periodically
and dynamic templates applied with the OS image and, optionally, periodically
at runtime.
Beowulf overview