The nova_availability_zone() fixture returns unexpected results against ironic environment

[Anna Babich]

The test stepler.nova.tests.test_metadata.test_put_metadata_on_instances_on_single_compute fails with 'No valid host found' (details are here - https://paste.mirantis.net/show/4379/) when it's run against the environment with ironic. It happens, because the nova_availability_zone() fixture returns all nodes where nova-compute service is enabled, including ironic node:

nova_availability_zone_hosts = ['node-4.test.domain.local', 'ironic-compute', 'node-6.test.domain.local']

According to this tests's scenario, we need to create 2 nova servers on host 1 and another 2 nova servers on host 2, and hosts are picked as host_1 = nova_availability_zone_hosts[0] and host_2 = nova_availability_zone_hosts[1]. So, the second node from nova_availability_zone_hosts list is taken to boot second pair of Nova servers on it, and test fails.

The nova_availability_zone() fixture should be refactored to filter ironic-compute node from its returned results.

[Alexander Gromov (agromov)]

Review link: https://review.gerrithub.io/#/c/347883/