HAProxy cannot bind socket [0.0.0.0:8888]

Thanks for you guys at first.
I have solved this issue by following command.
setsebool -P haproxy_connect_any=1

It works for me!

Add net.ipv4.ip_nonlocal_bind=1 on /etc/sysctl.conf

sysctl -p

Restart the haproxy service(service restart haproxy). it will work.

I would guess this is a SELinux issue. Try setenforce 0, then restart the HAProxy service. If HAProxy works after this change, restore the enforcing status with setenforce 1, and then run setsebool -P haproxy_connect_any to change the SELinux boolean that is probably affecting this, and restart the service again.