[SOLVED] Accessing /proc from inside a VM

dazdaz · 05-19-2012, 06:17 AM

I have access to a Linux virtual machine (KVM).

Is there any way or method of accessing /proc inside the virtual server ? I think that the virtualisation layer gets in the way...

Would be greatful for any pointers.

Ser Olmy · 05-19-2012, 09:45 AM

Do you want to access the /proc filesystem on the hypervisor host from the VM, or the other way around? What is it that you want to accomplish?

/proc is a virtual filesystem representing system resources, and the elements in it can be accessed like ordinary files and directories from within that system.

dazdaz · 05-19-2012, 09:59 AM

Quote:

Originally Posted by Ser Olmy

Do you want to access the /proc filesystem on the hypervisor host from the VM, or the other way around? What is it that you want to accomplish?

Hi, I want to access /proc from within the VM. I don't have access to the hypervisor host.

I am using the KVM VM as a development platform to write some scripts which need to access /proc but these scripts will be run on VMware VM's or directly on bare metal Linux boxes.

Quote:

/proc is a virtual filesystem representing system resources, and the elements in it can be accessed like ordinary files and directories from within that system.

Correct.

I presume that /sys using sysfs also can't be accessed. I think I am chasing a ghost here, what I want to do, does not seem possible.

Ser Olmy · 05-19-2012, 10:16 AM

Quote:

Originally Posted by dazdaz

Hi, I want to access /proc from within the VM. I don't have access to the hypervisor host.

You can access /proc on the VM, but not /proc on a different host (at least not directly).

Quote:

Originally Posted by dazdaz

I am using the KVM VM as a development platform to write some scripts which need to access /proc but these scripts will be run on VMware VM's or directly on bare metal Linux boxes.

If I understand you correctly, you want to test your scripts against the /proc entries on a hypervisor similar to the one they will actually be running on.

The problem is that not only can you not access the /proc filesystem of the hypervisor (or any other system) from within the VM, but the hypervisor environment is different from that of the hypervisor your scripts will be running on. Unless you're accessing both VMware and KVM through middleware like libvirt, it's unlikely that testing in a KVM environment will help. And if you are using libvirt, accessing /proc directly shouldn't really be necessary.

Why don't you get a free version of ESXi to test your scripts against? Or, if testing under KVM really is sufficient, use nested virtualization? (Yes, that actually works.)

dyasny · 05-20-2012, 11:46 AM

if you need to access a filesystem on the hypervisor rfom within a VM, the only way to do that is by running whatever commands you need to remotely. Same as you would execute commands on a remote host. I usually use ssh for that.

VMs should NOT and canNOT access the hypervisor, that's the whole idea, and if they can, it's a major security breach and not a feature.