An intra-cluster node troubleshooting method, wherein the method comprises: obtaining (210, 310) fault detection topology information of the cluster, wherein fault detection is performed on a node in the cluster, by at least one of other nodes in the cluster, and the fault detection topology information comprises a fault detection relationship between a detector node and a detected node in the cluster; receiving (220, 320) a fault indication message from the detector node, wherein the fault indication message is used to indicate unreachability from the detector node to the detected node; determining a sub-cluster of the cluster based on the fault detection topology information and the fault indication message, wherein nodes that belong to different sub-clusters are unreachable to each other; and determining (240, 340) a working cluster based on the sub-cluster of the cluster, wherein the working cluster is the sub-cluster having a largest quantity of nodes; wherein the determining a sub-cluster of the cluster based on the fault detection topology information and the fault indication message comprises: determining a fault detection relationship topology between nodes based on the fault detection topology information; wherein each edge in the fault detection relationship topology represents a detection relationship between the detector node and the detected node; deleting, from the fault detection relationship topology, an edge corresponding to the fault indication message; determining a connected subgraph of a fault detection relationship topology obtained after deletion; and determining the sub-cluster based on the connected subgraph of the fault detection relationship topology obtained after deletion. obtaining (210, 310) fault detection topology information of the cluster, wherein fault detection is performed on a node in the cluster, by at least one of other nodes in the cluster, and the fault detection topology information comprises a fault detection relationship between a detector node and a detected node in the cluster; receiving (220, 320) a fault indication message from the detector node, wherein the fault indication message is used to indicate unreachability from the detector node to the detected node; determining a sub-cluster of the cluster based on the fault detection topology information and the fault indication message, wherein nodes that belong to different sub-clusters are unreachable to each other; and determining (240, 340) a working cluster based on the sub-cluster of the cluster, wherein the working cluster is the sub-cluster having a largest quantity of nodes; wherein the determining a sub-cluster of the cluster based on the fault detection topology information and the fault indication message comprises: determining a fault detection relationship topology between nodes based on the fault detection topology information; wherein each edge in the fault detection relationship topology represents a detection relationship between the detector node and the detected node; deleting, from the fault detection relationship topology, an edge corresponding to the fault indication message; determining a connected subgraph of a fault detection relationship topology obtained after deletion; and determining the sub-cluster based on the connected subgraph of the fault detection relationship topology obtained after deletion. determining a fault detection relationship topology between nodes based on the fault detection topology information; wherein each edge in the fault detection relationship topology represents a detection relationship between the detector node and the detected node; deleting, from the fault detection relationship topology, an edge corresponding to the fault indication message; determining a connected subgraph of a fault detection relationship topology obtained after deletion; and determining the sub-cluster based on the connected subgraph of the fault detection relationship topology obtained after deletion.