Xtrabackup backup error

error log :
230202 09:30:23 Executing FLUSH NO_WRITE_TO_BINLOG BINARY LOGS
xtrabackup: Unknown error 1158
Error: failed to execute query ‘FLUSH NO_WRITE_TO_BINLOG BINARY LOGS’: 2013 (HY000) Lost connection to MySQL server during query

mysql8.0 variables:
wait_timeout=30
interactive_timeout=28800

mysql has not been restarted,backup for more than 8 hours;I wonder if the mysql connection is over interactive_timeout.

repl:

Hi @pangbin

xtrabackup is not an interactive session, so its connection should be closed after wait_timeout. However, xtrabackup sets wait timeout to its maximum value of 2147483.

Do you have any other process that look for long running idle connections and kills it, like pt-kill ?