[CentOS] Cannot boot CentOS 7 VM after updating Host CentOS 7 Kernel

[Paul R. Ganci]

On 10/30/2016 12:26 PM, Paul R. Ganci wrote:
> <snip>I am thinking of putting the CentOS iso out and then booting the 
> VM into it just to poke around the file system. Otherwise my other 
> option is to just clone a twin VM on another server and then just 
> change the networking IPs/hostname. Anybody have any other ideas as to 
> how to debug this problem?
So I booted off the CentOS-7-x86_64-DVD-1511.iso and everything looks 
just fine:

 > df
Filesystem                         1K-blocks        Used Available   
Use%   Mounted on
/dev/mapper/live-rw           2030899    949022    1077781     47% /
devtmpfs                           2004040              0 2004040       
0%   /dev
tmpfs                                 2023652              0 
2023652       0%   /dev/shm
tmpfs                                 2023652        8520 2015132       
1%   /run
tmpfs                                 2023652              0 
2023652       0%  /sys/fs/cgroup
/dev/sr1                             4227724  4227724 0   100%  
/run/install/repo
tmpfs                                 2023652          200 2023452       
1%  /tmp
/dev/mapper/centos-root  10799104  3894196    6904908     37% /mnt/sysimage
/dev/vda1                            508588     143516 365072     29%  
/mnt/sysimage/boot
tmpfs                                2023652               0 
2023652       0%  /mnt/sysimage/dev/shm

 > ls /mnt/sysimage
bin   boot   dev   etc   home   lib   lib64   media   misc   mnt net   
opt   proc   root    run    sbin   srv   sys    tmp   usr var

 > ls -l /mnt/sysimage/boot
total 109424
-rw-r--r--.    1 root root       126431  Oct 10 23:18 
config-3.10.0-327.36.2.el7.x86_64
drwxr-xr-x. 2 root root               26  Oct   2  2015  grub
drwx------.  6 root root             104  Oct 13 02:21  grub2
-rw-r--r--.    1 root root   40655493  Apr   3  2015 
initramfs-0-rescue-6494b5d98adc4f66b0cf4c19a0f6ab66.img
-rw-------.    1 root root   29666884 Oct 13  01:25 
initramfs-3.10.0-327.36.2.el7.x86_64.img
-rw-------.    1 root root   18119089  Oct 13 02:20 
initramfs-3.10.0-327.36.2.el7.x86_64kdump.img
-rw-r--r--.    1 root root   10190975  Dec 19  2015 initrd-plymouth.img
-rw-r--r--.    1 root root      252739  Oct  10 23:20 
symvers-3.10.0-327.36.2.el7.x86_64.gz
-rw-------.    1 root root    2965270  Oct  10 23:18 
System.map-3.10.0-327.36.2.el7.x86_64
-rwxr-xr-x.   1 root root    4902656  Apr    3  2015 
vmlinuz0-rescue-6494b5d98adc4f66b0cf4c19a0f6ab66
-rwxr-xr-x.   1 root root    5157936   Oct  10 23:18 
vmlinuz-3.10.0-327.36.2.el7.x86_64

So the CentOS DVD iso in linux rescue mode shows that everything is 
there and can be mounted. I guess that means somehow either grub itself 
is corrupted or one of the boot images. So is there a way for me to 
generate a new initrd while booted in linux resuce mode or will 
re-installing grub help? How would I attempt re-installing grub while 
booted in linux rescue mode?
-- 
Paul (ganci at nurdog.com)
Cell: (303)257-5208