A system management architecture is provided to manage plural compute nodes in a clustering system. Each of the compute nodes basically includes a BMC (Baseboard Management Controller) for local management. Among the compute nodes, a preset one has its BMC connecting with a management network switch through an extra network interface for clustering/system management. A first network interface, which is usually used to connect with the management network switch for communicating with other compute nodes, is utilized for the BMC of the preset compute node to connect with an external management host. A chipset on the preset compute node also connects with the external management host through a system I/O bus and the first network interface. On the preset compute node a operating system provides Network Address Translation service to allow the external management host to access each of the compute nodes.