If rabbitmq is deployed in a cluster then the ceilometer charm will
pass rabbitmq_hosts and rabbitmq_host to ceilometer-agent. This charm
was ignoring the rabbitmq_hosts key and thus always talking to a
single rabbit even if there were multiple.
Change-Id: I42c2e3ee4ee2bd1feb9815a4d9895a7121801995
Closes-Bug: #1670273
Adds improved pause and resume unit to the charm such tha the
charm stays paused during maintenance operations.
Sync latest version of charm-helpers for maintenance mode.
Amulet test for pause/resume actions
Change-Id: I3ec090fb9eb85561834b79003606c4d4b38dc84c