Inevitably, we're starting to hit cases where we have to think about compatibility when making changes to the prometheus output (same issues will apply to changes to perf counters that are passed through): https://github.com/ceph/ceph/pull/20506#issuecomment-368806208 For the moment, we don't have any policy around this, so I anticipate things changing at will until the point that we make a policy, which might naturally coincide with introducing the in-tree grafana dashboards (because at that point the prometheus output will be demonstrably reasonably complete). Thinking about what kind of policy we want, the extremes would be: - Do nothing: all counters can change at will (even though most of the time they won't) - Match Ceph protocol interop: all changes would be backwards compatible through two versions We will soon have some official grafana dashboards in the Ceph tree, which I anticipate most people using, but there will certainly be people who craft their own dashboards too. I'm hoping that the vendors shipping Ceph-based products will all be working with the in-tree dashboards, so this is probably more a topic of concern to large scale users. I think it's reasonable for people with custom dashboards to expect that we not knowingly break them with updates to our stable branches: that's a pretty easy thing for us to accomplish. The part that's probably more debatable is: should someone with an external dashboard built for luminous expect it to work seamlessly on mimic? I would say probably not. Because we make major internal changes between major releases, it's expected that various performance counters would go away or change in meaningful ways. Any thoughts? John -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
