Cephadm: Needs to pass cluster.listen-address to alertmanager
When using public IP with the ceph dashboard/monitoring, alert manager will not start with the following error message:
level=warn ts=2020-10-28T17:02:48 caller=cluster.go:154 component=cluster err="couldn't deduce an advertise address: no private IP found, explicit advertise add no provided" level=error ts=2020-10-28T17:02:48 caller=main.go:256 msg="unable to initialize gossip mesh" err="create member list: Failed to get find advertise address: No private IP address found, and explicit IP not provided"
Pass the ip of the node running alert manager using the extra flag "--cluster.listen-address=<ip>:9094" as part of the unit.run file.
In fact it seems passing any string instead of <ip> allows alert manager to start, just without gossip (clustering) which is probably ok in most cases.