Better error when no virtualization method is available on the server

[Chmouel Boudjnah]

When no hardware virtualisation is available (which is used on the default install) on the server and trying to run an instance nothing are get back to the user and the logs contains only an error like this :

==> /var/log/nova/nova-compute.log <==
2010-10-13 16:41:13+0100 [-] (root): ERROR instance 4014792697: Failed to spawn
2010-10-13 16:41:13+0100 [-] Traceback (most recent call last):
2010-10-13 16:41:13+0100 [-] File "/usr/lib/pymodules/python2.6/nova/compute/manager.py", line 86, in run_instance
2010-10-13 16:41:13+0100 [-] yield self.driver.spawn(instance_ref)
2010-10-13 16:41:13+0100 [-] File "/usr/lib/python2.6/dist-packages/twisted/internet/defer.py", line 893, in _inlineCallbacks
2010-10-13 16:41:13+0100 [-] result = g.send(result)
2010-10-13 16:41:13+0100 [-] File "/usr/lib/pymodules/python2.6/nova/virt/libvirt_conn.py", line 218, in spawn
2010-10-13 16:41:13+0100 [-] yield self._conn.createXML(xml, 0)
2010-10-13 16:41:13+0100 [-] File "/usr/lib/python2.6/dist-packages/libvirt.py", line 1289, in createXML
2010-10-13 16:41:13+0100 [-] if ret is None:raise libvirtError('virDomainCreateXML() failed', conn=self)
2010-10-13 16:41:13+0100 [-] libvirtError: internal error no supported architecture for os type 'hvm'
2010-10-13 16:41:13+0100 [-] Unhandled error in Deferred:
2010-10-13 16:41:13+0100 [-] Unhandled Error
        Traceback (most recent call last):

A more meaningful error would be nice for the users to enable virtualisation in BIOS.

[Rick Clark (dendrobates)]

is it libvirt's "no supported architecture for os type 'hvm'" that you think should be better, or are you saying we should catch that error and translate it to something more readable? The latter seems like a rabbit hole I don't want to go down.

[Jay Pipes (jaypipes)]

I think Chmouel is saying that if we could make the "no supported architecture for os type 'hvm'" message into something more useful like "Looks like hvm isn't enabled on this machine. Have you enabled virtualization in the BIOS?" :)

[Jay Pipes (jaypipes)]

I would say a fix for this bug would be a better error message PLUS putting some notes on HVM into our documentation! :)