Centos7升级内核

参考:

• https://blog.csdn.net/kikajack/article/details/79396793
• https://linux.cn/article-8310-1.html
• https://havee.me/linux/2017-01/upgrade-kernel-4-9-for-centos.html

# rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
# rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm
# yum --disablerepo="*" --enablerepo="elrepo-kernel" list available
# kernel-lt means long term version
# kernel-ml means main line version
# yum --enablerepo=elrepo-kernel install kernel-ml

查看可用内核

[root@localhost yum.repos.d]# awk -F\' '$1=="menuentry " {print i++ " : " $2}' /etc/grub2.cfg
0 : CentOS Linux (4.19.5-1.el7.elrepo.x86_64) 7 (Core)
1 : CentOS Linux (3.10.0-862.14.4.el7.x86_64) 7 (Core)
2 : CentOS Linux (4.4.145-1.el7.elrepo.x86_64) 7 (Core)
3 : CentOS Linux (3.10.0-693.el7.x86_64) 7 (Core)
4 : CentOS Linux (0-rescue-0863eef714ae4dbf8ee07fa05ed6ff82) 7 (Core)

设置默认启动

# grub2-set-default 'CentOS Linux (4.19.5-1.el7.elrepo.x86_64) 7 (Core)'

以后升级内核默认启用 kernel-ml

编辑文件 /etc/sysconfig/kernel

# DEFAULTKERNEL specifies the default kernel package type
DEFAULTKERNEL=kernel-ml

同时编辑文件 /etc/yum.repo.d/elrepo.repo，在 [elrepo-kernel] 下

enabled=1

开启bbr

# modprobe tcp_bbr
# echo "tcp_bbr" >> /etc/modules-load.d/modules.conf

# echo "net.core.default_qdisc=fq" >> /etc/sysctl.conf
# echo "net.ipv4.tcp_congestion_control=bbr" >> /etc/sysctl.conf
# sysctl -p

# lsmod | grep bbr
# sysctl net.ipv4.tcp_available_congestion_control
# sysctl net.ipv4.tcp_congestion_control