Issue
After creating a CentOS 7 VM, running "yum update" and rebooting causes the VM to fail to boot. The log shows: "Fatal: VM was not running 1 minute after being started", while the console will display a kernel panic and perhaps a failure to find a drive.
Environment
All OnApp Versions
CentOS 7 VMs built from OnApp template (possibly any VM upgraded / installed to CentOS 7)
Resolution
In the /boot/grub/grub.conf file, there is a missing line for the default kernel. The first entry should look similar to the older entry, the missing line is something like initrd /boot/initramfs-<kernel release>.img
Example lines from /boot/grub/grub.conf:
title CentOS Linux (3.10.0-229.1.2.el7.x86_64) 7 (Core)
root (hd0,0)
kernel /boot/vmlinuz-3.10.0-229.1.2.el7.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8
initrd /boot/initramfs-3.10.0-229.1.2.el7.x86_64.img
Simplest way to fix is from recovery mode. Mount the failed VM disk and edit file using vi or another text editor to add the missing initrd line.
