Comment 4 for bug 1599298

glance/0 was completing a db sync when the log dump was taken:

2016-07-04 00:23:27 INFO juju-log shared-db:37: Cluster leader, performing db sync
2016-07-04 00:23:28 INFO shared-db-relation-changed Option "verbose" from group "DEFAULT" is deprecated for removal. Its value may be silently ignored in the future.
2016-07-04 00:23:28 INFO shared-db-relation-changed /usr/lib/python2.7/dist-packages/oslo_db/sqlalchemy/enginefacade.py:1056: OsloDBDeprecationWarning: EngineFacade is deprecated; please use oslo_db.sqlalchemy.enginefacade
2016-07-04 00:23:28 INFO shared-db-relation-changed expire_on_commit=expire_on_commit, _conf=conf)

It looks like that was blocking - maybe that was the case for other services as well which might indicate some sort of underlying DB issue.