Comment 6 for bug 1847203

If you could add something to periodic_sync_routers_task() just to see if it returned, I'm assuming it just had nothing to to. Something like the LOG.debug before the return.

neutron/agent/l3/agent.py:

    def periodic_sync_routers_task(self, context):
        if not self.fullsync:
            LOG.debug("Not in fullsync, periodic_sync_routers_task returning early")
            return
        LOG.debug("Starting fullsync periodic_sync_routers_task")
    [...]

Also, what version of oslo-service do you have installed? That is the python library dealing with periodically running this function.