Comment 3 for bug 1896438

I'm also having the same issue in my running deployment.
My deployment is not even erroring out when trying to access the public endpoint of keystone, it just retries infinitely.
No proxy env, just public subnet is not available on the simplestreams container (neither switched, nor routed).
glance-simplestreams-sync.log is full with:

DEBUG * 09-21 16:08:01 [PID:47111] * keystoneclient.auth.identity.v3.base * Making authentication request to https://keystone.public.domain:5000/v3/auth/tokens
DEBUG * 09-21 16:08:01 [PID:47111] * urllib3.connectionpool * Starting new HTTPS connection (1): keystone.public.domain
INFO * 09-21 16:09:01 [PID:47125] * root * glance-simplestreams-sync started.
INFO * 09-21 16:09:01 [PID:47125] * root * /var/run/glance-simplestreams-sync.pid is locked, exiting
INFO * 09-21 16:10:02 [PID:47141] * root * glance-simplestreams-sync started.
INFO * 09-21 16:10:02 [PID:47141] * root * /var/run/glance-simplestreams-sync.pid is locked, exiting
INFO * 09-21 16:11:01 [PID:47375] * root * glance-simplestreams-sync started.