There is definitely some kind of infinite loop here:

Dec 13 14:43:21.412172 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]: /opt/stack/new/glance/glance/quota/__init__.py:168: ResourceWarning: unclosed <socket.socket fd=14, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=6, laddr=('104.130.211.192', 52252), raddr=('104.130.211.192', 8080)>
Dec 13 14:43:21.412563 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   return getattr(self.tags, name)
Dec 13 14:43:21.413081 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]: Fatal Python error: Cannot recover from stack overflow.
Dec 13 14:43:21.413440 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]: Thread 0x00007f4ff7ac8700 (most recent call first):
Dec 13 14:43:21.413817 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/usr/lib/python3.5/threading.py", line 297 in wait
Dec 13 14:43:21.414179 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/usr/lib/python3.5/threading.py", line 549 in wait
Dec 13 14:43:21.414511 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/usr/local/lib/python3.5/dist-packages/oslo_messaging/_drivers/impl_rabbit.py", line 926 in _heartbeat_thread_job
Dec 13 14:43:21.414869 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/usr/lib/python3.5/threading.py", line 862 in run
Dec 13 14:43:21.415584 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/usr/lib/python3.5/threading.py", line 914 in _bootstrap_inner
Dec 13 14:43:21.415951 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/usr/lib/python3.5/threading.py", line 882 in _bootstrap
Dec 13 14:43:21.416261 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]: Thread 0x00007f4ff8349700 (most recent call first):
Dec 13 14:43:21.416622 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/usr/lib/python3.5/threading.py", line 297 in wait
Dec 13 14:43:21.416995 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/usr/lib/python3.5/threading.py", line 549 in wait
Dec 13 14:43:21.417357 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/usr/local/lib/python3.5/dist-packages/oslo_messaging/_drivers/impl_rabbit.py", line 926 in _heartbeat_thread_job
Dec 13 14:43:21.417721 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/usr/lib/python3.5/threading.py", line 862 in run
Dec 13 14:43:21.418085 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/usr/lib/python3.5/threading.py", line 914 in _bootstrap_inner
Dec 13 14:43:21.418450 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/usr/lib/python3.5/threading.py", line 882 in _bootstrap
Dec 13 14:43:21.419113 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]: Current thread 0x00007f50070af780 (most recent call first):
Dec 13 14:43:21.419499 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/opt/stack/new/glance/glance/quota/__init__.py", line 168 in __getattr__
Dec 13 14:43:21.419875 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/opt/stack/new/glance/glance/quota/__init__.py", line 168 in __getattr__
Dec 13 14:43:21.421218 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/opt/stack/new/glance/glance/quota/__init__.py", line 168 in __getattr__
Dec 13 14:43:21.421577 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/opt/stack/new/glance/glance/quota/__init__.py", line 168 in __getattr__
Dec 13 14:43:21.421947 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/opt/stack/new/glance/glance/quota/__init__.py", line 168 in __getattr__
Dec 13 14:43:21.422307 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/opt/stack/new/glance/glance/quota/__init__.py", line 168 in __getattr__
Dec 13 14:43:21.422671 ubuntu-xenial-rax-ord-0001176665 <email address hidden>[6990]:   File "/opt/stack/new/glance/glance/quota/__init__.py", line 168 in __getattr__