Have you encountered a failure when you were executing pm2 install pm2-intercom? If you want to use log4js for stable log output in PM2's multiprocess mode, then using pm2-intercom-log4js for multiprocess log synchronization will be a good choice. It imitates the cooperation method of pm2-intercom + log4js, and aggregates the logs of the sub-processes to the main process for unified output, so as to avoid unpredictable exceptions in file reading or writing in multiprocess mode.