Sometime because of unsupported SFP interface won't come up so solution is to create following file to allow unsupported SFP.
create file /etc/modprobe.d/ixgbe.conf
alias ens2f0 ixgbe
alias ens2f1 ixgbe
options ixgbe allow_unsupported_sfp=1
rmmod ixgbe; modprobe ixgbe
add in /etc/default/grub file to fix the issue permanently
The answer, as with many things CentOS, is found in SELinux! While the apache user is able to open network connections, the httpd process (regardless of which user it's running as) isn't by default. The setting that controls it is httpd_can_network_connect, which can be set with
setsebool -P httpd_can_network_connect 1
Thanks to this question for helping me ...