[SOLVED] The virtual machine has terminated unexpectedly during startup because of signal 6

I am attempting to shutdown, backup and restart a VirtualBox virtual machine. The restart command is the usual:

$ VBoxManage startvm vname

When I run this from a cron job the start fails with the message:

VBoxManage: error: The virtual machine 'WIN7VM' has terminated unexpectedly during startup because of signal 6
VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component MachineWrap, interface IMachine

When the cron job runs, the user is currently logged onto KDE (i.e. a GUI exists for this user). If the user open a Konsole and runs the same command, it works, but doesn't work in that user's crontab.

I've posted this on the virtualbox.org forum and they are suggesting I post this here as they feel this is more Linux related than VirtualBox related.

Any idea why I can run this from KDE/Konsole/command line, but not from cron?

Any idea why I can run this from KDE/Konsole/command line, but not from cron?

Environment variables?

DISPLAY
VBOX_USER_HOME

Possibly:
VBOX_PROGRAM_PATH

Try prefixing the cron job with DISPLAY=0:.0 VBOX_USER_HOME=${Default Machine Folder}? Default Machine Folder is defined in the VirtualBox GUI Preferences.

cron jobs don't have any associated display, so you need to start the VM with

VBoxManage startvm name --type=headless

upnort: I'll try the suggested environment variables. None of the VBOX_ variable seen to exist. DISPLAY, yes. I've already tried setting the cron path to be the same as the login path.

55020: But if I start headless, the logged in user cannot see the VM, right? Perhaps upnort's suggested DISPLAY=0:.0 will work ...

But if I start headless, the logged in user cannot see the VM, right? Perhaps upnort's suggested DISPLAY=0:.0 will work ...

True, but there are ways to access a headless system. One way is configure the system with SSH. Or, if the VM does not run X, use something like TigerVNC. Similar to TigerVNC, another way is use the VirtualBox built-in Remote Display support (VirtualBox GUI->Display->Remote Display). After enabling, use the rdesktop command (part of the stock Slackware) to view the VM console. For example, rdesktop -N ${hostname|ip address}:3389.

For VMs I trust I tend to use Bridge mode and configure the VM as part of the LAN. SSH works great with that. I have another system that I used to run headless and I used the rdesktop trick to access the VM console. The VirtualBox Remote Display support works with normal VMs too and not just headless.

With respect to the original post, I suspect mising environment variables. When I have seen that in the past, from a terminal window running in X I dump `env | sort` to a text file. Then in the cron job I configure something to dump the same results. Then compare to find the missing variables. I am sure the missing DISPLAY is part of the problem and the missing VBOX variables could be too. Usually the VBOX variables don't matter if using the standard VirtualBox install directories. Another possible missing variable with the cron job might be $HOME.

I got it!! If I specify the crontab as:

49 12 * * * /bin/bash -c "DISPLAY=:0 $HOME/backupVM >> $HOME/backupVM.log 2>&1"

It works. Putting "DISPLAY=:0" in the actual backupVM script does not work.

Yes, I do use bridge mode and the VMs are part of the LAN. To log into the VM from a remote Windows workstation, I just use Remote Desktop Connection. I've not had the need to connect to the VM from Linux so I haven't used rdesktop. As far as the user on the Linux workstation running rdesktop, that is still an additional step versus the VM just being there when she gets into the office.