CentOS7.7升级内核至5.x
由于需要验证一个问题，需要将CentOS7内核升级至5.x版本
查看系统版本和内核版本
1 2 3 4 5 [root@k8s ~] CentOS Linux release 7.7.1908 (Core) [root@k8s ~] Linux k8s 3.10.0-1062.18.1.el7.x86_64
导入elrepo的key，并安装内核（elrepo）仓库
elrepo仓库支持Red Hat Enterprise Linux（RHEL）及其衍生版本（Scientific Linux，CentOS等）。
参考：http://elrepo.org/tiki/tiki-index.php
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 [root@k8s ~] [root@k8s ~] Loaded plugins: fastestmirror elrepo-release-7.el7.elrepo.noarch.rpm | 8.6 kB 00:00:00 Examining /var/tmp/yum-root-GHYeAv/elrepo-release-7.el7.elrepo.noarch.rpm: elrepo-release-7.0-5.el7.elrepo.noarch Marking /var/tmp/yum-root-GHYeAv/elrepo-release-7.el7.elrepo.noarch.rpm to be installed Resolving Dependencies --> Running transaction check ---> Package elrepo-release.noarch 0:7.0-5.el7.elrepo will be installed --> Finished Dependency Resolution Dependencies Resolved ============================================================================================================================================================================ Package Arch Version Repository Size ============================================================================================================================================================================ Installing: elrepo-release noarch 7.0-5.el7.elrepo /elrepo-release-7.el7.elrepo.noarch 5.0 k Transaction Summary ============================================================================================================================================================================ Install 1 Package Total size: 5.0 k Installed size: 5.0 k Is this ok [y/d/N]: y Downloading packages: Running transaction check Running transaction test Transaction test succeeded Running transaction Warning: RPMDB altered outside of yum. Installing : elrepo-release-7.0-5.el7.elrepo.noarch 1/1 Verifying : elrepo-release-7.0-5.el7.elrepo.noarch 1/1 Installed: elrepo-release.noarch 0:7.0-5.el7.elrepo Complete!
查看可用内核版本
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 [root@k8s ~] Loaded plugins: fastestmirror Determining fastest mirrors * elrepo-kernel: mirror-hk.koddos.net elrepo-kernel | 2.9 kB 00:00:00 elrepo-kernel/primary_db | 1.9 MB 00:00:00 Available Packages kernel-lt.x86_64 4.4.232-1.el7.elrepo elrepo-kernel kernel-lt-devel.x86_64 4.4.232-1.el7.elrepo elrepo-kernel kernel-lt-doc.noarch 4.4.232-1.el7.elrepo elrepo-kernel kernel-lt-headers.x86_64 4.4.232-1.el7.elrepo elrepo-kernel kernel-lt-tools.x86_64 4.4.232-1.el7.elrepo elrepo-kernel kernel-lt-tools-libs.x86_64 4.4.232-1.el7.elrepo elrepo-kernel kernel-lt-tools-libs-devel.x86_64 4.4.232-1.el7.elrepo elrepo-kernel kernel-ml.x86_64 5.8.0-1.el7.elrepo elrepo-kernel kernel-ml-devel.x86_64 5.8.0-1.el7.elrepo elrepo-kernel kernel-ml-doc.noarch 5.8.0-1.el7.elrepo elrepo-kernel kernel-ml-headers.x86_64 5.8.0-1.el7.elrepo elrepo-kernel kernel-ml-tools.x86_64 5.8.0-1.el7.elrepo elrepo-kernel kernel-ml-tools-libs.x86_64 5.8.0-1.el7.elrepo elrepo-kernel kernel-ml-tools-libs-devel.x86_64 5.8.0-1.el7.elrepo elrepo-kernel perf.x86_64 5.8.0-1.el7.elrepo elrepo-kernel python-perf.x86_64 5.8.0-1.el7.elrepo elrepo-kernel
yum安装kernel-ml 最新版内核
其中lt为4.4版本，ml是5.8版本，所以这里我们需要安装ml版本
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 [root@k8s ~] Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * elrepo: mirror-hk.koddos.net * elrepo-kernel: mirror-hk.koddos.net Resolving Dependencies --> Running transaction check ---> Package kernel-ml.x86_64 0:5.8.0-1.el7.elrepo will be installed --> Finished Dependency Resolution Dependencies Resolved ============================================================================================================================================================================ Package Arch Version Repository Size ============================================================================================================================================================================ Installing: kernel-ml x86_64 5.8.0-1.el7.elrepo elrepo-kernel 51 M Transaction Summary ============================================================================================================================================================================ Install 1 Package Total download size: 51 M Installed size: 232 M Downloading packages: kernel-ml-5.8.0-1.el7.elrepo.x86_64.rpm | 51 MB 00:00:03 Running transaction check Running transaction test Transaction test succeeded Running transaction Installing : kernel-ml-5.8.0-1.el7.elrepo.x86_64 1/1 Verifying : kernel-ml-5.8.0-1.el7.elrepo.x86_64 1/1 Installed: kernel-ml.x86_64 0:5.8.0-1.el7.elrepo Complete!
这里如果下载很慢，可以提前https://elrepo.org/linux/kernel/el7/x86_64/RPMS/ (手动下载包)在这里下载好
修改grub中默认的内核版本
查看默认的启动顺序
1 2 3 4 5 [root@k8s ~] CentOS Linux (5.8.0-1.el7.elrepo.x86_64) 7 (Core) CentOS Linux (3.10.0-1062.18.1.el7.x86_64) 7 (Core) CentOS Linux (3.10.0-1062.el7.x86_64) 7 (Core) CentOS Linux (0-rescue-20200426154603174201708213343640) 7 (Core)
修改cat /etc/default/grub，将GRUB_DEFAULT的值设置为0，重启后就会使用新内核
最后运行grub2-mkconfig刷新一下配置
1 2 3 4 5 6 7 8 9 10 11 [root@k8s ~] Generating grub configuration file ... Found linux image: /boot/vmlinuz-5.8.0-1.el7.elrepo.x86_64 Found initrd image: /boot/initramfs-5.8.0-1.el7.elrepo.x86_64.img Found linux image: /boot/vmlinuz-3.10.0-1062.18.1.el7.x86_64 Found initrd image: /boot/initramfs-3.10.0-1062.18.1.el7.x86_64.img Found linux image: /boot/vmlinuz-3.10.0-1062.el7.x86_64 Found initrd image: /boot/initramfs-3.10.0-1062.el7.x86_64.img Found linux image: /boot/vmlinuz-0-rescue-20200426154603174201708213343640 Found initrd image: /boot/initramfs-0-rescue-20200426154603174201708213343640.img done
重启主机，查看内核版本
1 2 [root@k8s ~] Linux k8s 5.8.0-1.el7.elrepo.x86_64
升级成功