An intra-cluster node troubleshooting method, wherein the method comprises: obtaining 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 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 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 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 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 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. <EOS>