# Cluster Training and Prediction¶

## 1. Network connection errors in the log during multi-node cluster training¶

There are maybe some errors in the log belonging to network connection problem during multi-node cluster training, for example, Connection reset by peer. This kind of error is usually caused by the abnormal exit of a training process in some node, and the other nodes cannot connect with this node any longer. Steps to troubleshoot the problem are as follows:

• Find the first error in the train.log, server.log, check whether other fault casued the problem, such as FPE, lacking of memory or disk.
• If the first error in server.log says “Address already used”, this may be caused by the port conflict of the non-exclusive execution. Connect the sys-admin to check if the current MPI cluster supports jobs submitted with parameter resource=full. If the current MPI cluster does not support this parameter, change the server port and try agian.
• If the current MPI cluster does not support exclusive pattern which allows a process to occupy the whole node, ask the administrator to replace or update the this cluster.