当前环境查看
uname -r
3.10.0-514.el7.x86_64安装新版本内核
rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm
yum --enablerepo=elrepo-kernel install kernel-ml -y查看当前已安装内核
查看已安装版本
rpm -qa | grep kernel
kernel-3.10.0-1062.18.1.el7.x86_64
kernel-tools-libs-3.10.0-1062.18.1.el7.x86_64
kernel-tools-3.10.0-1062.18.1.el7.x86_64
kernel-ml-devel-5.5.13-1.el7.elrepo.x86_64
kernel-3.10.0-957.el7.x86_64
kernel-headers-3.10.0-1062.18.1.el7.x86_64
kernel-ml-5.5.13-1.el7.elrepo.x86_64卸载安装的内核
rpm -e kernel-ml-devel-5.5.13-1.el7.elrepo.x86_64
rpm -e kernel-ml-5.5.13-1.el7.elrepo.x86_64查看启动项目
awk -F\' '$1=="menuentry " {print i++ " : " $2}' /etc/grub2.cfg
0 : CentOS Linux (5.5.13-1.el7.elrepo.x86_64) 7 (Core)
1 : CentOS Linux (3.10.0-1062.18.1.el7.x86_64) 7 (Core)
2 : CentOS Linux (3.10.0-957.el7.x86_64) 7 (Core)
3 : CentOS Linux (0-rescue-27c6b54f6ca241c6884f74f0193db5e9) 7 (Core)选择0号，5.5内核启动
grub2-set-default 0
#重启
reboot错误
选择5.5内核启动后，开机报错无法进入系统
/dev/centos/root does not exist解决方法
1. 启动时候选择'linux rescue'
2. 使用命令
dracut -f开启bbr
sysctl -a|grep tcp_congestion_control
net.ipv4.tcp_congestion_control = cubic // 当前拥塞控制算法是cubic