removing openstack-integrator unit failed

[Robert Gildein]

An error 'hook failed: "stop"' occurs while trying to remove the unit.
This error occurs when trying to obtain information about subnet (line [1]) where "BaseLBImpl.subnet" is an empty value.

Log output: [2]

juju version: 2.8.8-groovy-amd64
controller: 2.8.5

How I deployed:
```bash
juju deploy cs:bundle/charmed-kubernetes
juju deploy cs:~containers/openstack-integrator --trust
juju add-relation openstack-integrator kubernetes-master:openstack
juju add-relation openstack-integrator kubernetes-worker:openstack
```

How did I remove the unit:
```bash
juju remove-unit openstack-integrator/0
```

---
[1]: https://github.com/juju-solutions/charm-openstack-integrator/blob/e81840f2a14a2fd6d82eb31cd99c2662d8952346/lib/charms/layer/openstack.py#L705
[2]: https://pastebin.ubuntu.com/p/Dh8sPCfBdw/

[Vladimir Grevtsev (vlgrevtsev)]

Hi,

Still actual btw. However, as a workaround, the unit could be removed by forcibly terminating the machine via "juju remove-machine X --force".

[Robert Gildein (rgildein)]

PR: https://github.com/juju-solutions/charm-openstack-integrator/pull/46

[George Kraft (cynerva)]

Cherry-pick to stable branch: https://github.com/charmed-kubernetes/charm-openstack-integrator/commit/31893f8e424afe943f63b53316f93412c4865b35