Tempest test tempest.scenario.test_network_basic_ops.TestNetworkBasicOps.test_subnet_details fails when there is some additional nameserver configured in guest VM

[Slawek Kaplonski]

Error details:

Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/tempest/common/utils/__init__.py", line 89, in wrapper
    return f(*func_args, **func_kwargs)
  File "/usr/lib/python3.6/site-packages/tempest/scenario/test_network_basic_ops.py", line 615, in test_subnet_details
    trgt_serv=dns_servers))
  File "/usr/lib/python3.6/site-packages/testtools/testcase.py", line 411, in assertEqual
    self.assertThat(observed, matcher, message)
  File "/usr/lib/python3.6/site-packages/testtools/testcase.py", line 498, in assertThat
    raise mismatch_error
testtools.matchers._impl.MismatchError: {'1.2.3.4'} != {'1.2.3.4', '192.168.122.1'}: Looking for servers: ['1.2.3.4']. Retrieved DNS nameservers: ['192.168.122.1', '1.2.3.4'] From host: 10.0.0.217.

It's failing because there is additional nameserver 192.168.122.1 configured in guest vm in /etc/resolv.conf file.

I don't think that this is any real issue as this nameserver don't came from Neutron DHCP server for sure. So IMO it's simple bug in tempest that it should just check if all expected nameservers are configured properly but not fail in case when other servers are there too.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/703072

[Attila Fazekas (afazekas)]

Images with hardcoded 192.168.122.1 DNS server are broken.
I am not sure is there any real reason for tempest to allow random extra DNS servers comes from image.
We want to support relative wide variaty of images, but broken images are not included.

[Slawek Kaplonski (slaweq)]

In case of our d/s CI we are using RHEL image which has such server configured there. But what if anyone else will You any other own nameserver additionally hardcoded there? Should tempest be the tool to check if guest operating system is configured properly? IMO tempest is for testing OpenStack services and not guest OS.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Slawek Kaplonski (<email address hidden>) on branch: master
Review: https://review.opendev.org/703072

[Martin Kopec (mkopec)]

Closing this as discussed during the office hour: http://eavesdrop.openstack.org/meetings/qa/2020/qa.2020-11-03-14.01.log.html#l-177

[Martin Kopec (mkopec)]

This got reported again - https://bugs.launchpad.net/tempest/+bug/1914229 - and it's reevaluated - see https://bugs.launchpad.net/tempest/+bug/1914229/comments/6