Metal3 (metal-cubed) is a Kubernetes-native bare-metal provisioning stack. It exposes physical servers as BareMetalHost custom resources so a Kubernetes control plane can inspect, power, partition, and install them the same way it reconciles Deployments.
The core component is the baremetal-operator, which drives hosts via Ironic — the OpenStack bare-metal service — packaged as a container. Ironic handles the actual work: IPMI, Redfish, or iDRAC for power control; iPXE and virtual media for boot; inspection via ironic-python-agent; and image writing using qemu-img. On top of that, the Cluster API provider for Metal3 (CAPM3) turns BareMetalHosts into Cluster API Machines, so declaring a new worker becomes a matter of scaling a MachineDeployment, which provisions bare metal end-to-end without a separate automation layer.
Metal3 is the upstream of Red Hat OpenShift’s bare-metal installer and is used by SUSE Rancher and several telco edge distributions. It competes with MAAS, Tinkerbell, and vendor-specific provisioners, and its niche is giving Cluster API a true bare-metal infrastructure provider so the same declarative workflow used for AWS or vSphere clusters works on physical hardware.