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Metal³

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What Metal³ is

Metal³ is an open-source project for managing bare-metal infrastructure through Kubernetes. It can discover and enroll machines, inspect hardware, configure BIOS and RAID, clean disks, install operating system images, deploy Kubernetes, and perform rolling upgrades. The Bare Metal Operator handles host management and can also be used independently through the Kubernetes API; Cluster API is optional. Cluster API Provider Metal3 supports Cluster API-based clusters on bare-metal infrastructure. Metal³ uses OpenStack Ironic for provisioning, and Ironic can run as a standalone service without other OpenStack services. Supported machines use remote management protocols such as IPMI or Redfish and boot over the network with iPXE or, on compatible hardware, through virtual media. Supported architectures are x86_64 and AARCH64, but mixed-architecture clusters are not supported. Operating systems must be available in cloud image format, and first-boot configuration requires cloud-init or a similar tool in the image. Production guidance calls for hardening TLS, Ironic authentication, provisioning network access, and Bare Metal Operator permissions. Community support includes Kubernetes Slack, a mailing list, and a weekly call.

Who it suits

Metal³ suits teams provisioning on-premises Kubernetes nodes or managing bare-metal machines in testing and high-performance computing labs. It is for users able to work with Kubernetes and the listed image and provisioning requirements.

What it does well

  • Open-source tools manage bare-metal infrastructure with Kubernetes.
  • Bare Metal Operator can work without Cluster API.
  • Supports x86_64 and AARCH64 machines.
  • Community support includes Slack, a mailing list, and weekly calls.

What to know first

  • Ironic is the only supported provisioner.
  • Mixed-architecture clusters are not supported.
  • Images need cloud image format and cloud-init or similar for first boot.
  • Production deployments require security hardening.

Limits

Ironic is the sole supported provisioner, and mixed-architecture clusters are not supported. First-boot customization requires cloud-init or a similar tool in the operating-system image.

Getting started

  1. Prepare a Linux environment with Kubernetes access
  2. Connect hardware through IPMI or Redfish
  3. Provide network or compatible virtual-media boot
  4. Use an operating-system image in cloud format
  5. Run Metal³ with OpenStack Ironic
  6. Add cloud-init or a similar tool for first-boot customization

Verdict

Metal³ provides bare-metal discovery, provisioning, and Kubernetes cluster management, with Cluster API as an option rather than a requirement. Check the Ironic-only provisioner constraint, image prerequisites, and security guidance against your deployment needs.

Questions

Is Metal³ free?

Yes. Metal³ is an open-source project with a free model.

Which platforms does it support?

Its listed platforms are API, Linux, and self-hosted deployments.

Which machine architectures are supported?

Metal³ supports x86_64 and AARCH64, but not mixed-architecture clusters.

Can it run without Cluster API?

Yes. The Bare Metal Operator can provision through the Kubernetes API independently; Cluster API is optional.

What provisioner does Metal³ use?

OpenStack Ironic is currently the only supported provisioner and can run standalone.

What boot and image requirements apply?

Hardware can use IPMI or Redfish with network or virtual-media boot. Operating systems must be available in cloud image format.

Facts from Metal³'s own pages

Audience
The project describes use cases including provisioning on-premises Kubernetes cluster nodes and managing bare-metal machines in testing or high-performance computing labs. · metal3.io, 8 Oct 2026
Bare-metal lifecycle
Metal³ can enroll bare-metal machines, provision operating system images, and manage Kubernetes clusters deployed on them. · book.metal3.io, 8 Oct 2026
Cluster API
Cluster API Provider Metal3 enables users to deploy Cluster API-based clusters on bare-metal infrastructure using Metal³. · book.metal3.io, 8 Oct 2026
Community support
The project offers community support through Kubernetes Slack, a mailing list, and a weekly community call. · book.metal3.io, 8 Oct 2026
Deployment security
The security guide says quick-start defaults such as minimal TLS, an unauthenticated image server, and cluster-wide permissions are intended for evaluation rather than production. · book.metal3.io, 8 Oct 2026
Hardware limits
Only Ironic is currently supported as a provisioner, and the FAQ says support for other provisioners is not on the roadmap. · metal3.io, 8 Oct 2026
Hardware protocols
Metal³ supports network boot with iPXE and virtual media boot on compatible hardware using remote management protocols such as IPMI and Redfish. · book.metal3.io, 8 Oct 2026
Hardware support
The project supports x86_64 and AARCH64, but mixed-architecture clusters are not supported yet. · metal3.io, 8 Oct 2026
Host management
Bare Metal Operator inspects host hardware, can configure RAID and firmware, provisions images, and can clean disks before and after provisioning. · book.metal3.io, 8 Oct 2026
Operating system images
Metal³ can use operating systems available in a cloud image format, and first-boot customization requires cloud-init or a similar tool in the image. · metal3.io, 8 Oct 2026
Operating systems
Metal³ can install operating systems available in a cloud image format, and first-boot configuration requires cloud-init or a similar tool. · metal3.io, 8 Oct 2026
Project status
Metal³ is a Cloud Native Computing Foundation incubating project. · metal3.io, 8 Oct 2026
Provisioning
Metal³ can discover hardware, configure BIOS and RAID, clean disks, install operating system images, deploy Kubernetes, and perform rolling upgrades. · book.metal3.io, 8 Oct 2026
Provisioning backend
Metal³ uses OpenStack Ironic for bare-metal provisioning, and Ironic can run as a standalone service without other OpenStack services. · metal3.io, 8 Oct 2026
Provisioning limit
Ironic is currently the only supported provisioner; the FAQ says other provisioners are not on the current roadmap. · metal3.io, 8 Oct 2026
Provisioning protocols
Supported hardware uses remote management protocols such as IPMI and Redfish, with network boot or, on some hardware, virtual media boot. · book.metal3.io, 8 Oct 2026
Purpose
Metal³ is an open-source project that provides tools for managing bare-metal infrastructure using Kubernetes. · metal3.io, 8 Oct 2026
Security
The project directs suspected vulnerability reports to its security mailing list and documents severity assessment, fixes, and disclosure handling. · book.metal3.io, 8 Oct 2026
Security guidance
The security guide recommends hardening TLS, Ironic authentication, provisioning network access, and Bare Metal Operator permissions for production deployments. · book.metal3.io, 8 Oct 2026
Security reporting
The project asks that suspected vulnerabilities be reported to its [email protected] mailing list. · book.metal3.io, 8 Oct 2026
Standalone use
Cluster API is optional; the Baremetal Operator can be used independently through the Kubernetes API for bare-metal provisioning. · metal3.io, 8 Oct 2026
Support and community
The project guide lists Kubernetes Slack, a mailing list, and a weekly community call as ways to connect with the community. · book.metal3.io, 8 Oct 2026
Supported architectures
The FAQ lists x86_64 and AARCH64 support, but says mixed architectures are not supported yet. · metal3.io, 8 Oct 2026

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