CentOS7 Dracut lvm command not found
I updated CentOS7 kernel because of Meltdown issue from 3.10.0-693.11.1 to 3.10.0-693.11.6, but after that update, I cannot boot as centos drop to the dracut with error
warning /dev/mapper/centos-root does not exist
dracut:/# ls /dev/mapper/
control
dracut:/#
It looks like my initrd is wrongly configured, I can still boot 3.10.0-693.11.1 without any issue. I am trying to debug this (there are a lot resources online) but it looks that I am missing something fundamentally here as I cannot execute lvm command
dracut:/# lvm scan
sh: lvm: command not found
dracut:/# ls /etc/lvm/lvm.conf
ls: cannot access /etc/lvm/lvm.conf: No file or dictionary
dracut:/# ls /etc/lvm
ls: cannot access /etc/lvm: No file or dictionary
I saw that usually problem with tools is caused by missing binaries in /sbin, so I botted stabile kernel and checked:
root@localhost ~# ls /sbin/lvm
/sbin/lvm
root@localhost ~# which lvm
/sbin/lvm
So binary is at correct place, but for some reason dracut is not seeing it inside /sbin.
My grub configuration for 3.10.0-693.11.1 and 3.10.0-693.11.6 is almost identical
#: after update kernel params
linux16 /vmlinuz-3.10.0-693.11.6.el7.x86_64 root=/dev/mapper/centos-root ro crashkernel=128M rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rdshell
#: before update kernel params
linux16 /vmlinuz-3.10.0-693.11.1.el7.x86_64 root=/dev/mapper/centos-root ro crashkernel=128M rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rdshell
Here I struggled a little bit: I went through dracut man page and there a lot of options for LVM, I pressume autodiscovery is not working but why it works for previous kernel and newer has an issue? Also how I can get working lvm tools on initram, to debug it further?
Thank you for any advice!
UPDATE: Running lsinitrd -m -k show that there is no lvm module inside ramdisk
========================================================================
Image: /boot/initramfs-3.10.0-693.11.6.el7.x86_64.img: 18M
========================================================================
Early CPIO image
========================================================================
drwxr-xr-x 3 root root 0 Jan 22 11:15 .
-rw-r--r-- 1 root root 2 Jan 22 11:15 early_cpio
drwxr-xr-x 3 root root 0 Jan 22 11:15 kernel
drwxr-xr-x 3 root root 0 Jan 22 11:15 kernel/x86
drwxr-xr-x 2 root root 0 Jan 22 11:15 kernel/x86 /microcode
-rw-r--r-- 1 root root 24576 Jan 22 11:15 kernel/x86 /microcode/GenuineIntel.bin
========================================================================
Version: dracut-033-502.el7
dracut modules:
bash
nss-softokn
i18n
network
ifcfg
drm
plymouth
kernel-modules
qemu
resume
rootfs-block
terminfo
udev-rules
biosdevname
systemd
usrmount
base
fs-lib
shutdown
========================================================================
I was trying to add lvm kernel driver to initram image but unfortuneatly that failed without any visible issue:
dracut --add-drivers lvm /boot/initramfs-3.10.0-693.11.6.el7.x86_64.img
dracut[27939]: Failed to install module lvm
adding -v doesn't point to anything usefull.
Solution 1:
I had this problem. I fixed it by:
logging into a live cd (recovery should be fine too)
cp /etc/dracut.conf /etc/dracut.conf.bak
nano /etc/dracut.conf
Ammending the following lines to:
# dracut modules to add to the default
add_dracutmodules+="lvm"
# install local /etc/mdadm.conf
mdadmconf="yes"
# install local /etc/lvm/lvm.conf
lvmconf="yes"
(You probably won't need mdadmconf, I added it as I have Raid.)
Rerun dracut -f for my kernel. Reboot.
This got me passed the lvm issue. I now have issues sysroot not mounting (it drops me into a recovery shell). I will update when fixed.