1) If the number of connections for nofile is not configured in .service, the system's number of connections limit will be used
[root@localhost bin]# ulimit -n
1024
[root@localhost bin]# ulimit -Sn
1024
[root@localhost bin]# ulimit -Hn
4096
[root@localhost bin]# cat /proc/25168/limits
Limit Soft Limit Hard Limit Units
Max cpu time unlimited unlimited seconds
Max file size unlimited unlimited bytes
Max data size unlimited unlimited bytes
Max stack size 8388608 unlimited bytes
Max core file size unlimited unlimited bytes
Max resident set unlimited unlimited bytes
Max processes 126386 126386 processes
Max open files 1024 4096 files
Max locked memory 65536 65536 bytes
Max address space unlimited unlimited bytes
Max file locks unlimited unlimited locks
Max pending signals 126386 126386 signals
Max msgqueue size 819200 819200 bytes
Max nice priority 0 0
Max realtime priority 0 0
Max realtime timeout unlimited unlimited us
2) If the number of connections of nofile is configured in .service, it will affect the limit of the number of connections of this process
[Service] Restart=always ExecStartPre=********** ExecStart=********** WorkingDirectory=********** ExecReload=/bin/kill -HUP $MAINPID ExecStopPost=********** KillSignal=SIGKILL LimitNOFILE = 150000 LimitCORE=infinity
[root@localhost bin]# cat /proc/20082/limits
Limit Soft Limit Hard Limit Units
Max cpu time unlimited unlimited seconds
Max file size unlimited unlimited bytes
Max data size unlimited unlimited bytes
Max stack size 8388608 unlimited bytes
Max core file size unlimited unlimited bytes
Max resident set unlimited unlimited bytes
Max processes 126386 126386 processes
Max open files 150000 150000 files
Max locked memory 65536 65536 bytes
Max address space unlimited unlimited bytes
Max file locks unlimited unlimited locks
Max pending signals 126386 126386 signals
Max msgqueue size 819200 819200 bytes
Max nice priority 0 0
Max realtime priority 0 0
Max realtime timeout unlimited unlimited us