I have an Ubuntu 16.04 VM virtualized within a RHEL environment. I have no physical access to the server, and can only access the Ubuntu installation by SSH.
When I issue the reboot command to the Ubuntu VM, about a third of the time the VM will experience an error during the restart and instead boot into an emergency shell. I can't SSH to the VM when this happens, so I have to email the operators to hard-reboot the VM.
I need to determine what the cause of this error is. My plan is to reboot the VM until it drops to the emergency shell, then have the operators grab whatever info will help. They have access to the Ubuntu VM while it's in the emergency shell, the underlying RHEL OS, and the virtualization software running in RHEL. In addition, once the VM has been rebooted, I'll be able to examine error or log files in the Ubuntu system that persist across the emergency shell/reboot.
What information should I ask the operators to obtain in order to determine what keeps causing this problem? What information should I obtain from the Ubuntu VM itself once SSH is available?
