A cluster system comprising a plurality of nodes (201, 101, 102, 103), wherein each of the nodes (201, 101, 102, 103) has an operating system embedded therein, respectively, and is connected with the other nodes (201, 101, 102, 103) by a first network - LAN - and a second network - management LAN, and each node (201, 101, 102, 103) includes: a clusterware comprising a cluster controlling unit; and a first node managing unit configured to operate on the operating system and detect operation statuses of the other nodes (201, 101, 102, 103) via the first network - LAN -, the first node managing unit managing a first node list for holding identifiers, addresses and operation statuses of the plurality of nodes (201, 101, 102, 103); a baseboard management controller comprising a second node managing unit operating as firmware implemented on hardware so as to be configured to operate independently of the operating system and to detect operation statuses of the other nodes (201, 101, 102, 103) via the second network, the second node managing unit managing a second node list for holding identifiers and addresses of the plurality of nodes (201, 101, 102, 103); wherein the first node managing unit is configured to judge whether any of the other nodes (201, 101, 102, 103) is in a down state for a given time, based on results of the detection of the other nodes (201, 101, 102, 103) by the first node managing unit and the second node managing unit, wherein the second node managing unit is configured to receive an operation status request periodically from the first managing unit and is configured to detect that the operation status of the own node in the second managing unit is in a down state in case that there is no request for a given time, and wherein the cluster controlling unit is configured to execute a system switching process of causing another node (201, 101, 102, 103) than the node (201, 101, 102, 103) being in the down state to restart a service having been executed by the node (201, 101, 102, 103) being in the down state. a clusterware comprising a cluster controlling unit; and a first node managing unit configured to operate on the operating system and detect operation statuses of the other nodes (201, 101, 102, 103) via the first network - LAN -, the first node managing unit managing a first node list for holding identifiers, addresses and operation statuses of the plurality of nodes (201, 101, 102, 103); a baseboard management controller comprising a second node managing unit operating as firmware implemented on hardware so as to be configured to operate independently of the operating system and to detect operation statuses of the other nodes (201, 101, 102, 103) via the second network, the second node managing unit managing a second node list for holding identifiers and addresses of the plurality of nodes (201, 101, 102, 103); wherein the first node managing unit is configured to judge whether any of the other nodes (201, 101, 102, 103) is in a down state for a given time, based on results of the detection of the other nodes (201, 101, 102, 103) by the first node managing unit and the second node managing unit, wherein the second node managing unit is configured to receive an operation status request periodically from the first managing unit and is configured to detect that the operation status of the own node in the second managing unit is in a down state in case that there is no request for a given time, and wherein the cluster controlling unit is configured to execute a system switching process of causing another node (201, 101, 102, 103) than the node (201, 101, 102, 103) being in the down state to restart a service having been executed by the node (201, 101, 102, 103) being in the down state.