Bumped into this same thing, although with the private address, for unit.ceph-radosgw:

unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install ERROR private address not found
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install Traceback (most recent call last):
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/core/hookenv.py", line 1377, in network_get_primary_address
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     response = subprocess.check_output(
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/usr/lib/python3.8/subprocess.py", line 415, in check_output
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/usr/lib/python3.8/subprocess.py", line 516, in run
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     raise CalledProcessError(retcode, process.args,
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install subprocess.CalledProcessError: Command '['network-get', '--primary-address', 'admin']' returned non-zero exit status 1.
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install 
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install During handling of the above exception, another exception occurred:
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install 
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install Traceback (most recent call last):
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/contrib/network/ip.py", line 584, in get_relation_ip
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     address = network_get_primary_address(interface)
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/core/hookenv.py", line 1183, in inner_translate_exc2
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     return f(*args, **kwargs)
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/core/hookenv.py", line 1382, in network_get_primary_address
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     raise NoNetworkBinding("No network binding for {}"
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install charmhelpers.core.hookenv.NoNetworkBinding: No network binding for admin
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install 
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install During handling of the above exception, another exception occurred:
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install 
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install Traceback (most recent call last):
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/install.real", line 871, in <module>
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     assess_status(CONFIGS)
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/utils.py", line 279, in assess_status
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     assess_status_func(configs)()
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/contrib/openstack/utils.py", line 1787, in _assess_status_func
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     state, message = _determine_os_workload_status(*args, **kwargs)
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/contrib/openstack/utils.py", line 1033, in _determine_os_workload_status
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     state, message = _ows_check_generic_interfaces(
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/contrib/openstack/utils.py", line 1122, in _ows_check_generic_interfaces
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     incomplete_rel_data = incomplete_relation_data(configs,
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/contrib/openstack/utils.py", line 1406, in incomplete_relation_data
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     complete_ctxts = configs.complete_contexts()
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/contrib/openstack/templating.py", line 350, in complete_contexts
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     [interfaces.extend(i.complete_contexts())
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/contrib/openstack/templating.py", line 350, in <listcomp>
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     [interfaces.extend(i.complete_contexts())
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/contrib/openstack/templating.py", line 127, in complete_contexts
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     self.context()
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/contrib/openstack/templating.py", line 112, in context
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     _ctxt = context()
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/contrib/openstack/context.py", line 891, in __call__
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     laddr = get_relation_ip(ADDRESS_MAP[_addr_map_type]['binding'],
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/contrib/network/ip.py", line 590, in get_relation_ip
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     address = get_host_ip(unit_get('private-address'))
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/core/hookenv.py", line 92, in wrapper
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     res = func(*args, **kwargs)
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/var/lib/juju/agents/unit-ceph-radosgw-0/charm/hooks/charmhelpers/core/hookenv.py", line 869, in unit_get
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     return json.loads(subprocess.check_output(_args).decode('UTF-8'))
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/usr/lib/python3.8/subprocess.py", line 415, in check_output
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install   File "/usr/lib/python3.8/subprocess.py", line 516, in run
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install     raise CalledProcessError(retcode, process.args,
unit-ceph-radosgw-0: 00:17:20 WARNING unit.ceph-radosgw/0.install subprocess.CalledProcessError: Command '['unit-get', '--format=json', 'private-address']' returned non-zero exit status 1.