CentOS Online Upgrade Kernel

1. Upgrading the kernel requires the use of Elrepo's Yum source first we import the Elrepo key
   Rpm–import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org

2. Upgrading the kernel requires the use of Elrepo's Yum source

First we import Elrepo's key

RHEL-7, SL-7 or CentOS-7:  
rpm–import https://www.elrepo.org/ rpm-gpg-key-elrepo.org

RHEL-6, SL-6 or CentOS-6  
rpm-uvh http://www.elrepo.org/elrepo-release-6-6.el6.elrepo.noarch.rpm

* RHEL-5, SL-5 or centos-5*  
rpm-uvh http://www.elrepo.org/ elrepo-release-5-5.el5.elrepo.noarch.rpm

2. In the Elrepo source of yum,ml (mainline) is the kernel of the latest version of kernel lt Long-supported. The CentOS 7 default kernel version is the newest and this version of the kernel in the 3.10,yum source.

   Installing the ML kernel
   Yum–enablerepo=elrepo-kernel Install KERNEL-ML

   Installing the LT kernel
   Yum–enablerepo=elrepo-kernel Install Kernel-lt

4. modifying kernel boot order

    vi /etc/grub.conf # 里面是启动内核的序列，排在第一个的就是最新安装的内核。default是默认启动的内核，如果要选第一个，可以设置default=0即可。

6. Rebooting the system

     reboot

8. View Kernel version

    -r

CentOS Online Upgrade Kernel