adding space check when working with preallocation

[Dafna Ron]

when we run a large flavor on a setup configured for preallocation we fail to spown with unexpected error.
can we add a free space test before we launch the instance (like we have for min disk size)?
to reproduce, configure nova.conf for preallocation -> launch an instance with a flavor which is bigger than the compute disk

2014-05-15 19:12:57.183 23617 INFO nova.virt.libvirt.driver [req-1607bb0f-88a3-4888-b751-dab00e24f824 c9062d562d9f41e4a1fdce36a4f176f6 4ad766166539403189f2caca1ba306aa] [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] Creating image
2014-05-15 19:12:57.878 23617 ERROR nova.compute.manager [req-1607bb0f-88a3-4888-b751-dab00e24f824 c9062d562d9f41e4a1fdce36a4f176f6 4ad766166539403189f2caca1ba306aa] [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] Instance failed to spawn
2014-05-15 19:12:57.878 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] Traceback (most recent call last):
2014-05-15 19:12:57.878 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 1720, in _spawn
2014-05-15 19:12:57.878 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] block_device_info)
2014-05-15 19:12:57.878 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 2246, in spawn
2014-05-15 19:12:57.878 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] admin_pass=admin_password)
2014-05-15 19:12:57.878 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 2615, in _create_image
2014-05-15 19:12:57.878 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] project_id=instance['project_id'])
2014-05-15 19:12:57.878 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/imagebackend.py", line 196, in cache
2014-05-15 19:12:57.878 23617 TRACE n2014-05-15 19:12:58.471 23617 INFO nova.virt.libvirt.driver [req-1607bb0f-88a3-4888-b751-dab00e24f824 c9062d562d9f41e4a1fdce36a4f176f6 4ad766166539403189f2caca1ba306aa] [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] Deletion of /var/lib/nova/instances/c1ad975d-6974-4539-9a1d-c050a3abd339 complete
2014-05-15 19:12:59.093 23617 ERROR nova.compute.manager [req-1607bb0f-88a3-4888-b751-dab00e24f824 c9062d562d9f41e4a1fdce36a4f176f6 4ad766166539403189f2caca1ba306aa] [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] Error: Unexpected error while running command.
Command: fallocate -n -l 171798691840 /var/lib/nova/instances/c1ad975d-6974-4539-9a1d-c050a3abd339/disk
Exit code: 1
Stdout: ''
Stderr: 'fallocate: /var/lib/nova/instances/c1ad975d-6974-4539-9a1d-c050a3abd339/disk: fallocate failed: No space left on device\n'
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] Traceback (most recent call last):
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 1311, in _build_instance
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] set_access_ip=set_access_ip)
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 399, in decorated_function
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] return function(self, context, *args, **kwargs)
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 1723, in _spawn
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] LOG.exception(_('Instance failed to spawn'), instance=instance)
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/openstack/common/excutils.py", line 68, in __exit__
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] six.reraise(self.type_, self.value, self.tb)
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 1720, in _spawn
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] block_device_info)
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 2246, in spawn
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] admin_pass=admin_password)
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 2615, in _create_image
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] project_id=instance['project_id'])
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/imagebackend.py", line 196, in cache
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] utils.execute('fallocate', '-n', '-l', size, self.path)
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/utils.py", line 164, in execute
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] return processutils.execute(*cmd, **kwargs)
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] File "/usr/lib/python2.7/site-packages/nova/openstack/common/processutils.py", line 193, in execute
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] cmd=' '.join(cmd))
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] ProcessExecutionError: Unexpected error while running command.
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] Command: fallocate -n -l 171798691840 /var/lib/nova/instances/c1ad975d-6974-4539-9a1d-c050a3abd339/disk
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] Exit code: 1
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] Stdout: ''
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339] Stderr: 'fallocate: /var/lib/nova/instances/c1ad975d-6974-4539-9a1d-c050a3abd339/disk: fallocate failed: No space left on device\n'
2014-05-15 19:12:59.093 23617 TRACE nova.compute.manager [instance: c1ad975d-6974-4539-9a1d-c050a3abd339]
(END)

[Markus Zoeller (markus_z) (mzoeller)]

This wishlist bug has been open a year without any activity. I'm going to move it to "Opinion / Wishlist", which is an easily-obtainable queue of older requests that have come on.

In case you want to work on that, consider writing a blueprints [1] and spec [2]. I'll recommend to read [3] if not yet done. The effort to implement the requested feature is then driven only by the blueprint (and spec).

References:
[1] https://blueprints.launchpad.net/nova/
[2] https://github.com/openstack/nova-specs
[3] https://wiki.openstack.org/wiki/Blueprints