**OpenBMC** is an open source Linux distribution for baseboard management controllers (BMCs) — the small embedded computers built into every server motherboard that give operators out-of-band access to hardware regardless of whether the main OS is running. --- ### First Principle: You cannot manage hardware you cannot see. The BMC is the always-on window into every server. When the main OS crashes, hangs, or simply isn't installed yet, the BMC is still running. OpenBMC provides an open, inspectable firmware for this controller — replacing proprietary BMC firmware from Dell (iDRAC), HP (iLO), or Supermicro with a community-maintained, auditable alternative. --- ### Key Considerations - **Out-of-Band Management**: Provides power control, serial console, KVM-over-IP, and hardware sensor data (temperatures, fan speeds, voltages) independently of the host OS. - **Redfish API**: OpenBMC exposes a Redfish-compliant REST API — the industry standard for programmatic server management. This is how [[MAAS]] and [[Tinkerbell]] communicate with hardware. - **Security Transparency**: Closed-source BMC firmware is a known attack surface. OpenBMC allows operators to audit the firmware running on their hardware. - **Sensor Monitoring**: Feeds hardware health data into monitoring stacks like [[Zabbix]], which handles IPMI sensor polling that [[Prometheus]] doesn't cover natively. - **Origin**: From Facebook's Open Compute Project. Used by Facebook, Google, and hyperscalers running open hardware initiatives. --- ### How It Fits ``` OpenBMC (always-on BMC firmware, Redfish API) → [[MAAS]] / [[Tinkerbell]] (provisioning) → [[Zabbix]] (hardware health monitoring) ``` [[Bare Metal]] | [[MAAS]] | [[Tinkerbell]] | [[Zabbix]] | [[Open Source Hyperscaler MoC]]