大家好，我是架构君，一个会写代码吟诗的架构师。今天说一说dracut 查看linux分区,Centos进入dracut模式，报 /dev/centos/swap does not exist,如何恢复[通俗易懂],希望能够帮助大家进步!!!
1、问题介绍
本问题是在Centos7.7系统上部署k8s时，关闭了swap，手工删除/dev/centos/swap后出现的，
问题本身具有一定的普遍性
2、解决问题
2.1、进入dracut，挂载系统根分区
2.2、修改/etc/defaut/grub
dracut# mkdir tmp1
dracut# mount /dev/centos/root tmp1
dracut# vi tmp1/etc/defaut/grub
GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rhgb quiet"
修改为
GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=centos/root rhgb quiet"
2.3、挂载boot分区
2.3.1、找到boot分区设备
dracut# cat tmp1/etc/fstab
/etc/fstab
Created by anaconda on Thu Jan 2 21:15:59 2020
Accessible filesystems, by reference, are maintained under '/dev/disk'
See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
/dev/mapper/centos-root / xfs defaults 0 0
UUID=22747de8-b577-4bbb-9b5e-40c1b8c3c504 /boot xfs defaults 0 0
#/dev/mapper/centos-swap swap swap defaults 0 0
可以看到boot分区的设备UUID为
22747de8-b577-4bbb-9b5e-40c1b8c3c504
dracut# blkid
/dev/vda1: UUID="22747de8-b577-4bbb-9b5e-40c1b8c3c504" TYPE="xfs"
/dev/vda2: UUID="T7xTcp-ywWd-ciYc-k9mU-Fd3f-TCfe-wgKQgd" TYPE="LVM2_member"
UUID为
22747de8-b577-4bbb-9b5e-40c1b8c3c504对应的设备为/dev/vda1
2.3.2、挂载boot分区设备
dracut# mkdir tmp2
dracut# mount /dev/vda1 tmp2
2.3.2、修改grub.cfg
dracut# vi /tmp2/grub2/grub.cfg
删除下面两处的rd.lvm.lv=centos/swap
linux16 /vmlinuz-3.10.0-1062.el7.x86_64 root=/dev/mapper/centos-root ro crashkernel=auto rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rhgb quiet LANG=en_US.UTF-8
linux16 /vmlinuz-0-rescue-6f9bcc60986041238dcda79bfef462d5 root=/dev/mapper/centos-root ro crashkernel=auto rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rhgb quiet
改为
linux16 /vmlinuz-3.10.0-1062.el7.x86_64 root=/dev/mapper/centos-root ro crashkernel=auto rd.lvm.lv=centos/root rhgb quiet LANG=en_US.UTF-8
linux16 /vmlinuz-0-rescue-6f9bcc60986041238dcda79bfef462d5 root=/dev/mapper/centos-root ro crashkernel=auto rd.lvm.lv=centos/root rhgb quiet
保存退出
重启
reboot
