How OpenStack Ironic Enables Bare-Metal Provisioning in the Cloud

OpenStack Ironic is the OpenStack project module that provides physical‑machine (bare‑metal) management, offering a set of services for automated deployment and lifecycle operations of servers.

Since the J release, Ironic replaced the former “Bare Metal” driver in Nova. It relies on PXE boot and IPMI to perform mass deployment and power control, allowing most servers to be installed and managed through OpenStack just like virtual machines.

Ironic interacts with Keystone for authentication, Nova for compute API integration, Neutron for networking, Glance for image storage, and Cinder for block storage, enabling a seamless workflow where a user can request a bare‑metal instance via the same API used for virtual machines.

The core components are:

ironic-api : provides the RESTful northbound API.

ironic-conductor : the main service that executes commands received from the API.

nova-compute-ironic : the Nova driver that maps compute requests to Ironic.

ironic-provision : supplies TFTP services for PXE boot during OS installation.

During installation, Ironic services must be registered in Keystone, and Neutron supplies network connectivity for the bare‑metal nodes, while Glance supplies the images and Cinder provides volumes.

Physical‑machine resource discovery is handled by ironic-discoverd, which registers a server’s BMC address and automatically populates Ironic’s database and Nova’s compute_nodes table, after which PXE and IPMI are used for OS provisioning and power management.

Reasons for using Ironic include higher compute performance, access to hardware that cannot be virtualized, better database performance, enhanced security and isolation, and faster cloud‑infrastructure deployment.