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#使用cat /boot/grub2/grub.cfg |grep menuentry  查看系统可用内核

[root@bigapp-slave27 ~]# cat /boot/grub2/grub.cfg |grep menuentry

if [ x"${feature_menuentry_id}" = xy ]; then

  menuentry_id_option="--id"

  menuentry_id_option=""

export menuentry_id_option

menuentry 'CentOS Linux (3.10.0-514.16.1.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-327.el7.x86_64-advanced-6f5840d0-55ac-4d3b-899b-61c0297c5347' {

menuentry 'CentOS Linux (3.10.0-327.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-327.el7.x86_64-advanced-6f5840d0-55ac-4d3b-899b-61c0297c5347' {

menuentry 'CentOS Linux (0-rescue-d57307c454c0437d91c309347178cdf5) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-0-rescue-d57307c454c0437d91c309347178cdf5-advanced-6f5840d0-55ac-4d3b-899b-61c0297c5347' {

#查看当前内核

[root@bigapp-slave27 ~]# uname -r

3.10.0-514.16.1.el7.x86_64

#修改开机时默认使用的内核

grub2-set-default 'CentOS Linux (3.10.0-327.el7.x86_64) 7 (Core)'

#查看内核修改结果

[root@bigapp-slave27 ~]# grub2-editenv list

saved_entry=CentOS Linux (3.10.0-327.el7.x86_64) 7 (Core)

#查看系统安装了哪些内核包

[root@bigapp-slave27 ~]# rpm -qa |grep kernel

kernel-3.10.0-327.el7.x86_64

kernel-headers-3.10.0-514.6.1.el7.x86_64

kernel-tools-libs-3.10.0-327.el7.x86_64

kernel-3.10.0-514.16.1.el7.x86_64

kernel-tools-3.10.0-327.el7.x86_64

#使用yum remove 或rpm -e 删除无用内核

yum remove kernel-3.10.0-327.el7.x86_64