Install question about kernels

[azdour]

Hi,

I recently installed VirtualBox OSE and chose the wrong generic kernel. Do I need to remove the wrong generic kernel before installing the correct one? Or does VirtualBox intelligently detect which kernel I'm running under and load the correct module?

Thanks in advance.

Regards,

Tim.

[TerryE]

Both the VBox host drivers and the VBox Guest Additions must be linked against the correct kernel to work in both the host and guest OSs respectively. However given that the kernels are routinely upgraded, both include scripts to rebuild the necessary modules. In the case of the host, this is the /etc/init.d/vboxdrv setup command. Remember that you need the correct Linux kernel headers and the essential build tools installed for this to work.

[fixedwheel]

In the case of the host, this is the /etc/init.d/vboxdrv setup command.

Terry, the question is in Virtualbox OSE, the OP wrote OSE ... but vboxdrv setup is for the PUEL

@azdour install the kernel(s) you want but make sure you install the matching virtualbox-ose-modules package(s)

[TerryE]

Sorry my mistake. Doesn't the Debian OSE still have a vboxdrv module ?? It's certainly in src/VBox/Installer/linux/vboxdrv.sh.in in the OSE distro.

[fixedwheel]

Debian OSE still have a vboxdrv module ??

yes probably in the virtualbox-ose-modules packages

[azdour]

Hi,

Thanks for the replies. Although I still confused I've installed two kernels via the Ubuntu Synaptec Package Manager. Will VirtualBox know about both kernels and load the correct one - or should I only have one kernel?

I know it may all sound strange but I have a DRBL Server that runs on a different kernel to the clients that boot off it. The clients can run the software from the Server on their own hardware. I've installed the 386 kernel for the Server so that I can test it on the Server and it seems to work. I've also installed at the same time the kernel for the client. I have a sneaky feeling that VirtualBox is only seeing one of ther kernels - the kernel for the Server, which is why when the Client machine runs VirtualBox you get the 'kernel module' not found/loaded (or something similar).

Any further help would be greatly appreciated.

[Sasquatch]

VB can use multiple kernels without issues, but you have to install the module on it before it works. You do this by compiling the module. Normally, DKMS takes care of this, but it can be manually ran if you use "/etc/init.d/vboxdrv setup", which the OSE version should have by now.

[azdour]

Hi,

Thanks for the quick reply. Having done uname -a on both Server and Client I'm sure I've installed both 386 kernels so I'll keep on investigating why the Client says it may be missing.

[Sasquatch]

You mean about the VB kernel module? That's pretty obvious, it's not build on and for the kernel where you want to start it on. Rebuilding the module will certainly solve that.

[TerryE]

still confused I've installed two kernels via the Ubuntu Synaptec Package Manager. Will VirtualBox know about both kernels and load the correct one - or should I only have one kernel? ... I have a DRBL Server that runs on a different kernel to the clients that boot off it. The clients can run the software from the Server on their own hardware. I've installed the 386 kernel for the Server so that I can test it on the Server and it seems to work. I've also installed at the same time the kernel for the client. I have a sneaky feeling that VirtualBox is only seeing one of the kernels - the kernel for the Server, which is why when the Client machine runs VirtualBox you get the 'kernel module' not found/loaded (or something similar).

You need to go back to VM an Linux basics

1. The guest is a VM that is a different machine albeit virtual from the perspective of the OS that runs on it. The Host OS doesn't know or care about the guest OS and v.v.
2. You need to install virtualbox-ose module on the host and virtualbox-ose-guest on the guest
3. Whilst you can install multiple kernels on a Linux system, you will only boot one of these.
4. For virtualbox to work, it must be linked against the kernel that you've booted. You find this by the uname -r command. You can either do this by running the setup command as discussed about or picking the explicit version from Synaptec. So the umbrella package virtualbox-ose-modules-generic will in fact install the version for the latest generic kernel (which is what you use on a workstation). If you are booting a different version, say 2.6.24-23-generic then you need to install virtualbox-ose-modules-2.6.24-23-generic, etc.
5. If you kernel is upgraded by the update process then you need to load the new module for that kernel or relink the old one using setup.
6. If you boot with the alternate kernel then VBox won't work.

[azdour]

Hi Terry,

Thanks, your explanation has helped me understand more about VirtualBox and how it works. I'm going to try and get my server/client using the same kernel. VBox seems to work on the Server so I know the correct kernels are there, its just a case of updating the client to the same kernel.