Using docker virt driver (i.e. compute_driver = docker.DockerDriver in /etc/nova/nova.conf) -- if nova.virt.docker.driver.spawn() fails in setup_network(), the started container is not stopped prior to the driver reporting error.
A snippet from docker virt driver's spawn() method:
self.docker.start_container(container_id)
try:
self._setup_network(instance, network_info)
except Exception as e:
msg = _('Cannot setup network: {0}')
raise exception.InstanceDeployFailure(msg.format(e),
instance_id=instance['name'])
As shown above, the docker container is started and then networking is attempted -- if the _setup_network() call fails, and exception is raised but the docker container is left running... I had this happen to me and after the _setup_network() error I issued a "docker ps" command -- my container was still running until I stopped it manually with "docker stop CID".
The result of the above is container sprawl.
I also encounter this, will provide a patch later.