Enable BBR on CentOS 7
Execute the following script to install the latest kernel and enable BBR:
rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
yum --enablerepo=elrepo-kernel install kernel-ml -y
grub2-set-default 0
reboot
Enable BBR on CentOS 8
The kernel already includes BBR, just enable it directly:
echo "net.core.default_qdisc = fq" >> /etc/sysctl.conf
echo "net.ipv4.tcp_congestion_control = bbr" >> /etc/sysctl.conf
sysctl -p