yum和编译两种方式升级or降级Centos内核

[strong]今天探讨用yum和编译两种方式升级或者降级内核版本：[/strong]

升级：比如玩kvm，docker等虚拟化，centos内核则升级尤为重要（虽然2.6.x内核通过加载模块也可以玩，但是效果不如3.x）

降级：如果发现内核在危险漏洞列，降级内核则显得尤为重要。当然如果有特殊需求，也可以降级内核。

1、yum方式升级内核版本

1.1）查看当前系统内核版本

[code=bash;toolbar:false">[root@node4 ~]# cat /etc/redhat-release  CentOS release 6.6 (Final) [root@node4 ~]# uname -r 2.6.32-504.el6.x86_64 [root@node4 ~]#

[strong][root@node4 ~]# yum --enablerepo=elrepo-kernel  list  |grep kernel*  * elrepo-kernel: hkg.mirror.rackspace.com dracut-kernel.noarch                    004-356.el6               @anaconda-CentOS-201410241409.x86_64/6.6 kernel.x86_64                           2.6.32-504.el6            @anaconda-CentOS-201410241409.x86_64/6.6 kernel-firmware.noarch                  2.6.32-504.el6            @anaconda-CentOS-201410241409.x86_64/6.6 kernel-headers.x86_64                   2.6.32-573.18.1.el6       @updates       kernel-lt.x86_64                        3.10.104-1.el6.elrepo     @elrepo-kernel abrt-addon-kerneloops.x86_64            2.0.8-40.el6.centos       base           dracut-kernel.noarch                    004-409.el6_8.2           updates        erlang-kernel.x86_64                    R14B-04.3.el6             epel           kernel.x86_64                           2.6.32-642.11.1.el6       updates        kernel-abi-whitelists.noarch            2.6.32-642.11.1.el6       updates        kernel-debug.x86_64                     2.6.32-642.11.1.el6       updates        kernel-debug-devel.i686                 2.6.32-642.11.1.el6       updates        kernel-debug-devel.x86_64               2.6.32-642.11.1.el6       updates        kernel-devel.x86_64                     2.6.32-642.11.1.el6       updates        kernel-doc.noarch                       2.6.32-642.11.1.el6       updates        kernel-firmware.noarch                  2.6.32-642.11.1.el6       updates        kernel-headers.x86_64                   2.6.32-642.11.1.el6       updates        kernel-lt-devel.x86_64                  3.10.104-1.el6.elrepo     elrepo-kernel  kernel-lt-doc.noarch                    3.10.104-1.el6.elrepo     elrepo-kernel  kernel-lt-firmware.noarch               3.10.104-1.el6.elrepo     elrepo-kernel  kernel-lt-headers.x86_64                3.10.104-1.el6.elrepo     elrepo-kernel  kernel-ml.x86_64                        4.9.0-1.el6.elrepo        elrepo-kernel  kernel-ml-devel.x86_64                  4.9.0-1.el6.elrepo        elrepo-kernel  kernel-ml-doc.noarch                    4.9.0-1.el6.elrepo        elrepo-kernel  kernel-ml-firmware.noarch               4.9.0-1.el6.elrepo        elrepo-kernel  kernel-ml-headers.x86_64                4.9.0-1.el6.elrepo        elrepo-kernel  libreport-plugin-kerneloops.x86_64      2.0.9-32.el6.centos       base           perf.x86_64                             4.9.0-1.el6.elrepo        elrepo-kernel  php-symfony-http-kernel.noarch          2.3.42-1.el6              epel           [root@node4 ~]#[p][strong]#default=1 default=0[p][strong][root@node4 ~]# cat /etc/redhat-release  CentOS release 6.6 (Final) [root@node4 ~]# uname -r 3.10.104-1.el6.elrepo.x86_64 [root@node4 ~]#[p][strong]make menuconfig（出现图形）

[p][strong][root@node4 ~]# shutdown -r now[p][strong]dracut-kernel.noarch                    004-356.el6               @anaconda-CentOS-201410241409.x86_64/6.6 kernel.x86_64                           2.6.32-504.el6            @anaconda-CentOS-201410241409.x86_64/6.6 kernel-firmware.noarch                  2.6.32-504.el6            @anaconda-CentOS-201410241409.x86_64/6.6 kernel-headers.x86_64                   2.6.32-573.18.1.el6       @updates       kernel-lt.x86_64                        3.10.104-1.el6.elrepo     @elrepo-kernel abrt-addon-kerneloops.x86_64            2.0.8-40.el6.centos       base           dracut-kernel.noarch                    004-409.el6_8.2           updates        erlang-kernel.x86_64                    R14B-04.3.el6             epel           kernel.x86_64                           2.6.32-642.11.1.el6       updates        kernel-abi-whitelists.noarch            2.6.32-642.11.1.el6       updates        kernel-debug.x86_64                     2.6.32-642.11.1.el6       updates        kernel-debug-devel.i686                 2.6.32-642.11.1.el6       updates        kernel-debug-devel.x86_64               2.6.32-642.11.1.el6       updates        kernel-devel.x86_64                     2.6.32-642.11.1.el6       updates        kernel-doc.noarch                       2.6.32-642.11.1.el6       updates        kernel-firmware.noarch                  2.6.32-642.11.1.el6       updates        kernel-headers.x86_64                   2.6.32-642.11.1.el6       updates        kernel-lt-devel.x86_64                  3.10.104-1.el6.elrepo     elrepo-kernel  kernel-lt-doc.noarch                    3.10.104-1.el6.elrepo     elrepo-kernel  kernel-lt-firmware.noarch               3.10.104-1.el6.elrepo     elrepo-kernel  kernel-lt-headers.x86_64                3.10.104-1.el6.elrepo     elrepo-kernel  kernel-ml.x86_64                        4.9.0-1.el6.elrepo        elrepo-kernel  kernel-ml-devel.x86_64                  4.9.0-1.el6.elrepo        elrepo-kernel  kernel-ml-doc.noarch                    4.9.0-1.el6.elrepo        elrepo-kernel  kernel-ml-firmware.noarch               4.9.0-1.el6.elrepo        elrepo-kernel  kernel-ml-headers.x86_64                4.9.0-1.el6.elrepo        elrepo-kernel  libreport-plugin-kerneloops.x86_64      2.0.9-32.el6.centos       base           perf.x86_64                             4.9.0-1.el6.elrepo        elrepo-kernel  php-symfony-http-kernel.noarch          2.3.42-1.el6              epel           [root@node4 ~]#[p][strong]