Unable to get device_path from network mounted volume in extend in use

[Jose Castro Leon]

While implementing support for extending in-use volumes for RBD, I've hit a bug as the code relies on the server having access to the devices that are visible in its filesystem through the device path. On network attached volumes in which the qemu process directly access the device over the network, this device_path attribute does not exist that leads to an exception.

https://github.com/openstack/nova/blob/master/nova/virt/libvirt/driver.py#L1636

...
            state = guest.get_power_state(self._host)
            active_state = state in (power_state.RUNNING, power_state.PAUSED)
            if active_state:
                disk_path = connection_info['data']['device_path'] <=====
                LOG.debug('resizing block device %(dev)s to %(size)u kb',
                          {'dev': disk_path, 'size': new_size})
                dev = guest.get_block_device(disk_path)
...

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/590188

[Jose Castro Leon (jose-castro-leon)]

In order to expose it, I've added the implementation for extend in-use RBD volumes that depend on os-brick

https://review.openstack.org/#/c/589925/1

[Matt Riedemann (mriedem)]

I'm going to close this since it's not a bug, it's just required for this blueprint:

https://blueprints.launchpad.net/nova/+spec/extend-in-use-rbd-volumes

We can track the changes with the blueprint.