I see this on the nova log of one compute node and this is a resize command. The test creates flavors and instances and tries to resize the instances.

2016-08-31 21:15:38.313 21152 ERROR oslo_messaging.rpc.dispatcher [req-4c45e6c9-9e06-4147-99ca-554ffe1f74c4 70994e5e921148d19fff94094c2d805c bfbe6062011b4a0ab1023cc275e4f0e2 - - -] Exception during message handling: Resize error: not able to execute ssh command: Unexpected error while running command.
Command: ssh 172.16.0.94 mkdir -p /var/lib/nova/instances/842ee219-acfa-4155-8140-b4b14ca2d4c0
Exit code: 255
Stdout: u''

The above ssh command is run from one compute node to the other.
This will never work unless its ssh [email protected]..