centos7多个启动项开机默认启动顺序设置
centos服务器每次重启都会启动最新内核版本，有时候我不希望启动最新的，由于和现在某些软件不兼容，还是想选择旧的版本，下面是如何开机启动你的旧版本内核
1.如果你想要删除最新的版本，很好办
使用：uname -r 查看现在使用的版本，现在这个内核版本也可能不是你想要的，如果你不知道你的内核版本，请重启，选择你想要的内核版本，记住你想要的内核版本，或者进入你所需要的内核版本，然后使用该命令查看
[root@root ~]# uname -r
3.10.0-514.21.2.el7.x86_64 #这个就是你的内核版本号然后我们需要看我们当前都有哪些内核版本
[root@root ~]# rpm -qa | grep kernel
kernel-tools-libs-3.10.0-514.21.2.el7.x86_64
kernel-tools-3.10.0-514.21.2.el7.x86_64
kernel-3.10.0-514.el7.x86_64 #最老的版本
kernel-3.10.0-514.21.2.el7.x86_64 #现在的版本
kernel-3.10.0-693.11.6.el7.x86_64 #最新的版本,是我想要删除的版本，直接使用yum remove kernel-3.10.0-693.11.6.el7.x86_64
abrt-addon-kerneloops-2.1.11-45.el7.centos.x86_64
abrt-addon-kerneloops-2.1.11-48.el7.centos.x86_64
kernel-headers-3.10.0-693.11.6.el7.x86_64
kernel-headers-3.10.0-514.21.2.el7.x86_64
kernel-tools-libs-3.10.0-693.11.6.el7.x86_64
kernel-tools-3.10.0-693.11.6.el7.x86_64 然后reboot即可
2.如果还想保留现在的版本
[root@root ~]# find / -name grub.cfg
/boot/grub2/grub.cfg[root@root ~]# vi /boot/grub2/grub.cfg
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub2-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#
### BEGIN /etc/grub.d/00_header ###
set pager=1
if [ -s $prefix/grubenv ]; then
load_env
fi
if [ "${next_entry}" ] ; then
set default="${next_entry}"
set next_entry=
save_env next_entry
set boot_once=true
else
set default="${saved_entry}"
fi
if [ x"${feature_menuentry_id}" = xy ]; then
menuentry_id_option="--id"
else
menuentry_id_option=""
fi
export menuentry_id_option
if [ "${prev_saved_entry}" ]; then
set saved_entry="${prev_saved_entry}"
save_env saved_entry
set prev_saved_entry=
save_env prev_saved_entry
set boot_once=true
fi
function savedefault {
if [ -z "${boot_once}" ]; then
saved_entry="${chosen}"
save_env saved_entry
fi
}
function load_video {
if [ x$feature_all_video_module = xy ]; then
insmod all_video
else
insmod efi_gop
insmod efi_uga
insmod ieee1275_fb
insmod vbe
insmod vga
insmod video_bochs
insmod video_cirrus
fi
}
terminal_output console
if [ x$feature_timeout_style = xy ] ; then
set timeout_style=menu
set timeout=5
# Fallback normal timeout code in case the timeout_style feature is
# unavailable.
else
set timeout=5
fi
### END /etc/grub.d/00_header ###
### BEGIN /etc/grub.d/00_tuned ###
set tuned_params=""
### END /etc/grub.d/00_tuned ###
### BEGIN /etc/grub.d/01_users ###
if [ -f ${prefix}/user.cfg ]; then
source ${prefix}/user.cfg
if [ -n "${GRUB2_PASSWORD}" ]; then
set superusers="root"
export superusers
password_pbkdf2 root ${GRUB2_PASSWORD}
fi
fi
### END /etc/grub.d/01_users ###
### BEGIN /etc/grub.d/10_linux ### #下面的menuentry是你启动项，从上往下是启动顺序，你可以自己调整menuentry 'CentOS Linux (3.10.0-693.11.6.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-514.el7.x86_64-advanced-429ab68a-d2a3-40ea-90b3-368bed7ccb64' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_msdos
insmod xfs
set root='hd0,msdos1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint='hd0,msdos1' 24b97fca-87b5-4af0-a204-93aaeb7f286c
else
search --no-floppy --fs-uuid --set=root 24b97fca-87b5-4af0-a204-93aaeb7f286c
fi
linux16 /vmlinuz-3.10.0-693.11.6.el7.x86_64 root=/dev/mapper/cl_nodejs-root ro crashkernel=auto rd.lvm.lv=cl_nodejs/root rd.lvm.lv=cl_nodejs/swap rhgb quiet LANG=en_US.UTF-8
}
menuentry 'CentOS Linux (3.10.0-514.21.2.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-514.el7.x86_64-advanced-429ab68a-d2a3-40ea-90b3-368bed7ccb64' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_msdos
insmod xfs
set root='hd0,msdos1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint='hd0,msdos1' 24b97fca-87b5-4af0-a204-93aaeb7f286c
else
search --no-floppy --fs-uuid --set=root 24b97fca-87b5-4af0-a204-93aaeb7f286c
fi
linux16 /vmlinuz-3.10.0-514.21.2.el7.x86_64 root=/dev/mapper/cl_nodejs-root ro crashkernel=auto rd.lvm.lv=cl_nodejs/root rd.lvm.lv=cl_nodejs/swap rhgb quiet LANG=en_US.UTF-8
initrd16 /initramfs-3.10.0-514.21.2.el7.x86_64.img
}
menuentry 'CentOS Linux (3.10.0-514.el7.x86_64) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-514.el7.x86_64-advanced-429ab68a-d2a3-40ea-90b3-368bed7ccb64' {
load_video
set gfxpayload=keep
insmod gzio
insmod part_msdos
insmod xfs
set root='hd0,msdos1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint='hd0,msdos1' 24b97fca-87b5-4af0-a204-93aaeb7f286c
else
search --no-floppy --fs-uuid --set=root 24b97fca-87b5-4af0-a204-93aaeb7f286c
fi
linux16 /vmlinuz-3.10.0-514.el7.x86_64 root=/dev/mapper/cl_nodejs-root ro crashkernel=auto rd.lvm.lv=cl_nodejs/root rd.lvm.lv=cl_nodejs/swap rhgb quiet LANG=en_US.UTF-8
initrd16 /initramfs-3.10.0-514.el7.x86_64.img
}
menuentry 'CentOS Linux (0-rescue-353f5985435f32df26dfdb5d4f9bc2a9) 7 (Core)' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-0-rescue-353f5985435f32df26dfdb5d4f9bc2a9-advanced-429ab68a-d2a3-40ea-90b3-368bed7ccb64' {
load_video
insmod gzio
insmod part_msdos
insmod xfs
set root='hd0,msdos1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint='hd0,msdos1' 24b97fca-87b5-4af0-a204-93aaeb7f286c
else
search --no-floppy --fs-uuid --set=root 24b97fca-87b5-4af0-a204-93aaeb7f286c
fi
linux16 /vmlinuz-0-rescue-353f5985435f32df26dfdb5d4f9bc2a9 root=/dev/mapper/cl_nodejs-root ro crashkernel=auto rd.lvm.lv=cl_nodejs/root rd.lvm.lv=cl_nodejs/swap rhgb quiet
initrd16 /initramfs-0-rescue-353f5985435f32df26dfdb5d4f9bc2a9.img
}
### END /etc/grub.d/10_linux ###
### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###
### BEGIN /etc/grub.d/20_ppc_terminfo ###
### END /etc/grub.d/20_ppc_terminfo ###
### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###
### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###
### BEGIN /etc/grub.d/41_custom ###
if [ -f ${config_directory}/custom.cfg ]; then
source ${config_directory}/custom.cfg
elif [ -z "${config_directory}" -a -f $prefix/custom.cfg ]; then
source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###