os.rename causes rabbitmq-server charm to fail if /tmp and /etc sit on different partitions

[Pedro Guimarães]

Using latest charm from cs:rabbitmq-server
Ubuntu Xenial distro

When deployed, charm is failing at config-changed hook with:

Traceback (most recent call last):
  File "./hooks/config-changed", line 972, in <module>
    hooks.execute(sys.argv)
  File "/var/lib/juju/agents/unit-landscape-rabbitmq-server-1/charm/charmhelpers/core/hookenv.py", line 914, in execute
    self._hooks[hook_name]()
  File "/var/lib/juju/agents/unit-landscape-rabbitmq-server-1/charm/hooks/rabbit_utils.py", line 885, in wrapped_f
    f(*args, **kwargs)
  File "/var/lib/juju/agents/unit-landscape-rabbitmq-server-1/charm/charmhelpers/contrib/hardening/harden.py", line 93, in _harden_inner2
    return f(*args, **kwargs)
  File "./hooks/config-changed", line 788, in config_changed
    rabbit.update_hosts_file({cluster_ip: rabbit.get_unit_hostname()})
  File "/var/lib/juju/agents/unit-landscape-rabbitmq-server-1/charm/hooks/rabbit_utils.py", line 740, in update_hosts_file
    os.rename(tmpfile.name, HOSTS_FILE)
OSError: [Errno 18] Invalid cross-device link: '/tmp/tmplitmyyi7' -> '/etc/hosts'

os.rename do not work if we have source and destination sitting on different partitions.

Digging on this error, I've found:
Following: https://github.com/google/clusterfuzz-tools/pull/360

Which basically replaces os.rename for shutil.move function.
Manually applying this same change fixed the problem and rerunning the hook fixed the issue.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/680494

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/680494
Committed: https://git.openstack.org/cgit/openstack/charm-rabbitmq-server/commit/?id=fb1b4bec0ff838e4af15058ae015e5ee6842c12a
Submitter: Zuul
Branch: master

commit fb1b4bec0ff838e4af15058ae015e5ee6842c12a
Author: David Ames <email address hidden>
Date: Thu Sep 5 12:05:00 2019 -0700

    Use shutil.move rather than os.rename

    When the source and destination file paths are not on the same partition
    os.rename raises OSError: [Errno 18] Invalid cross-device link.

    Use shutil.move instead.

    Change-Id: I28d6cb6c15a4496243fab7ec6c7eedcd1422f4c2
    Closes-Bug: #1833804

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/19.07
Review: https://review.opendev.org/680635

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/680635
Committed: https://git.openstack.org/cgit/openstack/charm-rabbitmq-server/commit/?id=ba24fa2056ea5e5870470425dd0a99e428f1729c
Submitter: Zuul
Branch: stable/19.07

commit ba24fa2056ea5e5870470425dd0a99e428f1729c
Author: David Ames <email address hidden>
Date: Thu Sep 5 12:05:00 2019 -0700

    Use shutil.move rather than os.rename

    When the source and destination file paths are not on the same partition
    os.rename raises OSError: [Errno 18] Invalid cross-device link.

    Use shutil.move instead.

    Change-Id: I28d6cb6c15a4496243fab7ec6c7eedcd1422f4c2
    Closes-Bug: #1833804
    (cherry picked from commit fb1b4bec0ff838e4af15058ae015e5ee6842c12a)