Install elrepo & new kernel
rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org rpm -Uvh http://elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm yum --enablerepo=elrepo-kernel install kernel-ml -y
Lets understand in which position our new kernel installs. Rows begins with 0, so if you see new kernel on the top you should choose grub-set-default 0
egrep ^menuentry /etc/grub2.cfg | cut -f 2 -d \' grub2-set-default 0 reboot
Check that our new kernel install successfully.
uname -r
Lets enable BBR
echo 'net.core.default_qdisc=fq' | sudo tee -a /etc/sysctl.conf echo 'net.ipv4.tcp_congestion_control=bbr' | sudo tee -a /etc/sysctl.conf sysctl -p
And lets check that our bbr module enabled successfully.
# Check if BBR is enabled, output should be "bbr cubic reno" sysctl net.ipv4.tcp_available_congestion_control # Verify, output should be bbr sysctl -n net.ipv4.tcp_congestion_control # Check that module loads, output should be (tcp_bbr 20480 1) lsmod | grep bbr
When new kernel released just update it via yum and check new grub-set-default.
yum update --enablerepo=elrepo-kernel egrep ^menuentry /etc/grub2.cfg | cut -f 2 -d \' grub2-set-default 0 reboot
For autoload new kernel after update edit file /etc/default/grub and set GRUB_DEFAULT=0
GRUB_TIMEOUT=1 GRUB_DEFAULT=0 GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)" GRUB_DEFAULT=0 GRUB_DISABLE_SUBMENU=true GRUB_TERMINAL_OUTPUT="console" GRUB_CMDLINE_LINUX="no_timer_check console=tty0 console=ttyS0,115200n8 net.ifnames=0 biosdevname=0 elevator=noop crashkernel=auto" GRUB_DISABLE_RECOVERY="true"