For : [alert] 2685#0: setrlimit(RLIMIT_NOFILE, 100000) failed (1: Operation not permitted)

check whether 

# sestatus -b | grep httpd_setrlimit
httpd_setrlimit off
# setsebool -P httpd_setrlimit on
# sestatus -b | grep httpd_setrlimit
httpd_setrlimit on

#httpd_setrlimit - allows Nginx to adjust the number of file descriptors

Hope this helps.  Thanks Eugene for nice ajenti.