A number of users have experienced problems with rebooting and getting a kernel panic after upgrading using the VB GUI "Start Upgrade" button: see http://vortexbox.org/threads/3649-SO...ate-and-Reboot and http://vortexbox.org/threads/3632-No...-error-message
The apparent cause is an update of the VB web server (httpd) in an upgrade that also installs a new kernel (kernel-PAE). The update of httpd gets an error, and somehow this causes a faulty/incomplete kernel install. Rebooting after the upgrade causes a kernel panic when trying to load the faulty kernel. See http://info.vortexbox.org/tiki-index...e=Kernel+Panic for a way to fix this problem.
User nunovi has found that upgrading from the command line does not have this issue; see http://vortexbox.org/threads/3685-Ke...-some-insights
So, until the VB GUI code is fixed, it may be a good idea to upgrade from the command line instead of from the VB GUI.
Here's how to do it:
1. Login to your VB; see Login.
2. To update, enter
3. A reboot is only needed if the update installed a new kernel – look for an install of the kernel-PAE package.
yum clean all; yum update
If a new kernel was installed, reboot to use it. Enter
4. If you're doing this from a remote login, "reboot" will close the session. You'll have to wait for the VB to complete the reboot before you can login remotely again.
This info is also available in the wiki: CLI Upgrade