centos7 内核如何升级

需求：由于客户容器化的需要，需要将当前的操作系统升级为5.10.7的版本。

内核升级操作步骤如下：

步骤一：载入公钥、安装elrepo

rpm -import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm

步骤二、载入elrepo-kernel元数据

yum --disablerepo=\* --enablerepo=elrepo-kernel repolist

步骤三、查看可用rpm、并且安装

• 查看可用安装（其中关键字 lt 是稳定版、 mt标识是最新版）

[root@cainiao-k8s-hz-basic-25 ~]# yum --disablerepo=\* --enablerepo=elrepo-kernel list kernel*
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * elrepo-kernel: mirrors.neusoft.edu.cn
Installed Packages
kernel.x86_64                                                                                                                                            3.10.0-1160.el7                                                                                                                              @anaconda
kernel.x86_64                                                                                                                                            3.10.0-1160.11.1.el7                                                                                                                         @updates
kernel-devel.x86_64                                                                                                                                      3.10.0-1160.11.1.el7                                                                                                                         @updates
kernel-headers.x86_64                                                                                                                                    3.10.0-1160.11.1.el7                                                                                                                         @updates
kernel-ml.x86_64                                                                                                                                         5.10.7-1.el7.elrepo                                                                                                                          @elrepo-kernel
kernel-ml-devel.x86_64                                                                                                                                   5.10.7-1.el7.elrepo                                                                                                                          @elrepo-kernel
kernel-ml-tools.x86_64                                                                                                                                   5.10.7-1.el7.elrepo                                                                                                                          @elrepo-kernel
kernel-ml-tools-libs.x86_64                                                                                                                              5.10.7-1.el7.elrepo                                                                                                                          @elrepo-kernel
Available Packages
kernel-lt.x86_64                                                                                                                                         5.4.89-1.el7.elrepo                                                                                                                          elrepo-kernel
kernel-lt-devel.x86_64                                                                                                                                   5.4.89-1.el7.elrepo                                                                                                                          elrepo-kernel
kernel-lt-doc.noarch                                                                                                                                     5.4.89-1.el7.elrepo                                                                                                                          elrepo-kernel
kernel-lt-headers.x86_64                                                                                                                                 5.4.89-1.el7.elrepo                                                                                                                          elrepo-kernel
kernel-lt-tools.x86_64                                                                                                                                   5.4.89-1.el7.elrepo                                                                                                                          elrepo-kernel
kernel-lt-tools-libs.x86_64                                                                                                                              5.4.89-1.el7.elrepo                                                                                                                          elrepo-kernel
kernel-lt-tools-libs-devel.x86_64                                                                                                                        5.4.89-1.el7.elrepo                                                                                                                          elrepo-kernel
kernel-ml-doc.noarch                                                                                                                                     5.10.7-1.el7.elrepo                                                                                                                          elrepo-kernel
kernel-ml-headers.x86_64                                                                                                                                 5.10.7-1.el7.elrepo                                                                                                                          elrepo-kernel
kernel-ml-tools-libs-devel.x86_64

• 安装

yum -y --enablerepo=elrepo-kernel install kernel-ml.x86_64 kernel-ml-tools.x86_64
yum remove kernel-tools-libs.x86_64 kernel-tools.x86_64

步骤四：查看系统上的所有可用内核

[root@cainiao-k8s-hz-basic-25 ~]# awk -F\' '$1=="menuentry " {print $2}' /etc/grub2.cfg
CentOS Linux (5.10.7-1.el7.elrepo.x86_64) 7 (Core)
CentOS Linux (3.10.0-1160.11.1.el7.x86_64) 7 (Core)
CentOS Linux (3.10.0-1160.el7.x86_64) 7 (Core)
CentOS Linux (0-rescue-20201228113502924739250506992733) 7 (Core)
[root@maitao-k8s-hz-basic-25 ~]# vim /etc/default/grub

步骤五：设置开机从新内核启动

• 方法1:

grub2-set-default 0

• 方法2:

编辑配置文件 vim /etc/default/grub
将GRUB_DEFAULT=saved改为GRUB_0=saved，保存退出vim。

步骤六：运行grub2-mkconfig命令来重新创建内核配置

grub2-mkconfig -o /boot/grub2/grub.cfg

步骤七、重启动、查看内核、更新

reboot
uname -r
yum update


升级版本
[root@cainiao-k8s-hz-rancher ~]# uname -r
5.10.7-1.el7.elrepo.x86_64