centos 升级内核版本为最新版

一、检查内核版本

[root@web1 ~]# uname -r
3.10.0-514.el7.x86_64
[root@web1 ~]# cat /etc/redhat-release 
CentOS Linux release 7.3.1611 (Core) 
[root@web1 ~]#

二、如何升级内核

1、导入 elrepo 的 key 然后在安装 elrepo 的 yum 源：

rpm -import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org ###key
rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm ###yum源
　

查看可用的内核相关的包

yum --disablerepo="*" --enablerepo="elrepo-kernel" list available

 [root@web1 ~]# yum --disablerepo="*" --enablerepo="elrepo-kernel" list available
 Loaded plugins: fastestmirror, langpacks
elrepo-kernel | 2.9 kB 00:00:00 
 elrepo-kernel/primary_db | 1.8 MB 00:00:02 
 Loading mirror speeds from cached hostfile
 * elrepo-kernel: mirrors.tuna.tsinghua.edu.cn
 Available Packages
 kernel-lt.x86_64 4.4.180-2.el7.elrepo elrepo-kernel
 kernel-lt-devel.x86_64 4.4.180-2.el7.elrepo elrepo-kernel
 kernel-lt-doc.noarch 4.4.180-2.el7.elrepo elrepo-kernel
 kernel-lt-headers.x86_64 4.4.180-2.el7.elrepo elrepo-kernel
 kernel-lt-tools.x86_64 4.4.180-2.el7.elrepo elrepo-kernel
 kernel-lt-tools-libs.x86_64 4.4.180-2.el7.elrepo elrepo-kernel
 kernel-lt-tools-libs-devel.x86_64 4.4.180-2.el7.elrepo elrepo-kernel
 kernel-ml.x86_64 5.1.5-1.el7.elrepo elrepo-kernel
 kernel-ml-devel.x86_64 5.1.5-1.el7.elrepo elrepo-kernel
 kernel-ml-doc.noarch 5.1.5-1.el7.elrepo elrepo-kernel
 kernel-ml-headers.x86_64 5.1.5-1.el7.elrepo elrepo-kernel
 kernel-ml-tools.x86_64 5.1.5-1.el7.elrepo elrepo-kernel
 kernel-ml-tools-libs.x86_64 5.1.5-1.el7.elrepo elrepo-kernel
 kernel-ml-tools-libs-devel.x86_64 5.1.5-1.el7.elrepo elrepo-kernel
 perf.x86_64 5.1.5-1.el7.elrepo elrepo-kernel
 python-perf.x86_64 5.1.5-1.el7.elrepo

 

3、安装内核（我这里用最新的吧）以后如何继续升级直接用下面这条命令就可以了

yum -y --enablerepo=elrepo-kernel install kernel-ml

 

三、修改 grub 中默认的内核版本并重启

内核升级完成后，还需要调整

1、查看内核启动顺序

awk -F\' '$1=="menuentry " {print i++ " : " $2}' /etc/grub2.cfg

通过此命令可以看到新内核顺序为 0

 

 

 [root@web1 ~]# awk -F\' '$1=="menuentry " {print i++ " : " $2}' /etc/grub2.cfg
 0 : CentOS Linux (6.3.3-1.el7.elrepo.x86_64) 7 (Core)
 1 : CentOS Linux (3.10.0-1160.90.1.el7.x86_64) 7 (Core)
 2 : CentOS Linux (3.10.0-1160.71.1.el7.x86_64) 7 (Core)
 3 : CentOS Linux (0-rescue-8ac29b96fb6a484caa42e28ce6f398bc) 7 (Core)
 [root@web1 ~]# grub2-set-default 0
 [root@web1 ~]# reboot