Comment 2 for bug 1606882

If I would like to have tenant/project specific API on "planned host maintenance state" of a specific host(id), it should not matter if it is expensive. Actually this API could be used by tenant after querying his servers via Nova API to query any more specific host(id) state information that is not in "Nova DB" (but perhaps in Craton).

In host fault situation if the same would be used, it would be too expensive (slow). Anyhow in this situation, I would not expect Craton to be involved, but actions done directly from "monitoring" (actually in OPNFV Doctor we can use what ever monitoring SW and we implement "inspector" component like Vitrage that get the raw alarm from monitors and as this "inspector" is then the one first to know the problem and it knows the cloud topology (host, vms, tenants...), it can act on it very fast (mark host down, trigger notif/alarm, call evacuation or some external flow).) Tenant need to know about fault in milliseconds not to compromise any subscriber action like ongoing phone call.