nobody    6248  6241  0 10:51 ?        00:00:00 nginx: worker process       
nobody    6249  6241  0 10:51 ?        00:00:00 nginx: worker process       
nobody    6250  6241  0 10:51 ?        00:00:01 nginx: worker process       
nobody    6251  6241  0 10:51 ?        00:00:02 nginx: worker process       
nobody    6252  6241  0 10:51 ?        00:00:00 nginx: cache manager process 
luming    8680 25051  0 10:56 pts/1    00:00:00 grep --color=auto nginx 

Congratulations! You can upgrade your Nginx server gracefully.