~~UNDERCONSTRUCTION~~

The Intelligent Platform Management Interface (IPMI) specification is an Intel led standard which defines a set of common interfaces to a computer system which system administrators can use to monitor system health and manage the system. An IPMI sub-system operates independently of the operating system and allows administrators to manage a system remotely even in the absence of an operating system or the system management software, or even if the monitored system is powered off, but connected to a power source.

IPMI uses what is called a side-band LAN connection, which utilizes the board Network Interface Controller (NIC). This connection utilizes a System Management Bus (SMBUS) interface between the BMC (Baseboard Management Controller) and the board Network Interface Controller (NIC). This allows to reduce costs while still enabling sufficient bandwidth to utilize a text console even when the remote computer is down.

The Baseboard Management Controller (BMC) is the main controller of an IPMI sub-system. Other management controllers are also present that are referred to as “satellite” controllers. The satellite controllers within the same chassis connect to the BMC via the system interface called IPMB (Intelligent Platform Management Bus/Bridge), an enhanced implementation of I²C (Inter-Integrated Circuit). A specialized wire protocol, the Remote Management Control Protocol (RMCP), is used to manage it.

Dell PowerEdge servers have implemented standards-based IPMI hardware monitoring on most of the server line. For instance, the PowerEdge R905 provides an IPMI interface version 2.0, with support for KCS interface.

Two points are worth to highlights:

• the BMC piggybacks on the first built-in NIC .This, this interface must be network attached on the hosts we want to manage. However, please note that it uses its own IP address, so you need an extra one;
• most of the IPMI commands that shut the host down also kill the BMC. If that happens you’ll need to go power the machine on manually. Thus, be prepared to push the power button until you figure out exactly what works fine according your needs.

You will need a Linux host to send the IPMI commands from. Undoubtedly there are ways to send these commands from other operating systems, but I don't care since I am a penguin's friend.

To use IPMI remotely, first of all the controlled system must be configured. This can be done either through the boot-time menu (Ctrl-E) or using the OpenIPMI tools within the OS of the controlled system. This last option requires: a proper kernel configuration and a collection of tools.

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