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Grendel

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What Grendel is

Grendel is a free, open-source bare-metal provisioning system for organizations that need to boot Linux servers over a network, particularly in High Performance Computing environments. It provides DHCP, PXE, TFTP, DNS, and HTTP services, with diskful and stateless live-image provisioning. It can boot Linux kernel and initrd images, including LiveOS images, and discover hosts from switch queries, DHCP traffic, lease files, or tab-delimited imports. For hardware management, it controls BMC and iDRAC interfaces through RedFish and IPMI.

An HTTP API powers both the command-line client and built-in Web UI. Its TCP listener uses token authentication and role-based access controls, with admin, user, and read-only roles. HTTPS can be configured, and the documentation also covers HTTPS provisioning and signed boot images. Grendel can provide tagged node groups to ClusterShell clush. Linux tar.gz, deb, and rpm packages and a container image are available. The project is developed by the University at Buffalo Center for Computational Research, whose documentation describes production use on clusters of 200 to 1500 nodes.

Who it suits

Grendel suits organizations provisioning server racks for HPC clusters. Its documentation assumes basic HPC, Linux, and networking knowledge.

What it does well

  • Supports diskful and stateless live-image provisioning.
  • Discovers hosts through several methods, including switch queries.
  • Controls BMC and iDRAC through RedFish and IPMI.
  • Offers a built-in Web UI and command-line client.
  • Provides token authentication and role-based access controls.

What to know first

  • Database changes are lost on restart unless persistence is configured.
  • It is not a recursive DNS resolver.
  • HTTPS is recommended for remote API access.

Limits

Unless installed with an rpm or deb package, the database is in memory by default; changes are lost on restart unless disk persistence is configured. Grendel is not a recursive DNS resolver, and production deployments are recommended to run it behind a stub resolver such as unbound.

Getting started

  1. Open the Grendel documentation website.
  2. Choose a Linux tar.gz, deb, or rpm package, or a container image.
  3. Configure database persistence if required, especially for installations other than rpm or deb.
  4. Set up provisioning services and host discovery for the cluster.
  5. Configure API access and HTTPS when remote access is needed.
  6. Use the Web UI or command-line client through the HTTP API.

Verdict

Grendel brings network boot, host discovery, and hardware management into one provisioning system. Plan for database persistence and a separate stub resolver in production deployments.

Questions

Is Grendel free?

Yes. Grendel is free and open source.

Which platforms does it support?

The listed platforms are API, Linux, self-hosted, and web.

What does Grendel provision?

It provides DHCP, PXE, TFTP, DNS, and HTTP services for provisioning Linux systems over a network, with diskful and stateless live-image modes.

How can Grendel find hosts?

It can query a switch, snoop DHCP packets, read a dhcpd.leases file, or import a tab-delimited file.

What installation options are available?

The documentation provides Linux tar.gz, deb, and rpm packages, along with a container image.

Does Grendel provide access controls?

Its TCP API listener uses token authentication and role-based access control, with admin, user, and read-only roles.

Facts from Grendel's own pages

Access controls
The TCP listener uses token authentication and role-based access control, with built-in admin, user, and read-only roles. · grendel.readthedocs.io, 3 Oct 2026
API and interface
An HTTP API powers both the Grendel CLI and built-in Web UI. · grendel.readthedocs.io, 3 Oct 2026
Boot images
Grendel supports booting Linux kernel and initrd images, including LiveOS images. · grendel.readthedocs.io, 3 Oct 2026
Database persistence
Unless installed with an rpm or deb package, the database is in memory by default and changes are lost on restart unless disk persistence is configured. · grendel.readthedocs.io, 2 Oct 2026
Deployment
The project provides precompiled Linux tar.gz, deb, and rpm packages, plus a container image. · grendel.readthedocs.io, 3 Oct 2026
DNS limit
Grendel is not a recursive DNS resolver; the production deployment guide recommends running it behind a stub resolver such as unbound. · grendel.readthedocs.io, 3 Oct 2026
DNS limitation
Grendel is not a recursive DNS resolver; production deployments are recommended to run it behind a stub resolver such as unbound. · grendel.readthedocs.io, 2 Oct 2026
Hardware control
It supports BMC/iDRAC control via RedFish and IPMI. · grendel.readthedocs.io, 2 Oct 2026
Hardware management
It supports BMC and iDRAC control through RedFish and IPMI. · grendel.readthedocs.io, 3 Oct 2026
Headquarters
Buffalo, NY · grendel.readthedocs.io, 28 Sept 2026
Host discovery
It can discover hosts by querying a switch, snooping DHCP packets, reading a dhcpd.leases file, or importing a tab-delimited file. · grendel.readthedocs.io, 3 Oct 2026
HTTPS
The API can use HTTPS when a key and certificate are configured, and provisioning over HTTPS and signed boot images are also documented. · grendel.readthedocs.io, 3 Oct 2026
Installation
The documentation provides Linux tar.gz, deb and rpm packages, plus a container image. · grendel.readthedocs.io, 2 Oct 2026
Integration
Grendel can serve as a group source for ClusterShell clush, using tags to filter nodes. · grendel.readthedocs.io, 3 Oct 2026
Intended users
The documentation assumes HPC, Linux, and networking knowledge and describes administrators using Grendel to deploy physical compute clusters. · grendel.readthedocs.io, 3 Oct 2026
Maker and use
Grendel is developed by the University at Buffalo Center for Computational Research and the docs say it runs CCR production clusters ranging from 200 to 1500 nodes. · grendel.readthedocs.io, 3 Oct 2026
Persistence limit
Unless installed from an rpm or deb package, its database is in memory by default and changes are lost on restart unless persistence is configured. · grendel.readthedocs.io, 3 Oct 2026
Provisioning
It provides DHCP, PXE, TFTP, DNS, and HTTP services for provisioning Linux systems over a network. · grendel.readthedocs.io, 3 Oct 2026
Provisioning modes
It supports diskful and stateless live-image provisioning. · grendel.readthedocs.io, 2 Oct 2026
Purpose
Grendel is a bare-metal provisioning system for High Performance Computing Linux clusters. · grendel.readthedocs.io, 3 Oct 2026
Security
The TCP API listener uses token authentication with role-based access control; HTTPS is recommended for remote access. · grendel.readthedocs.io, 2 Oct 2026

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