Only request metric collections for hosts connected to the MS

Author: GaOrtiga

server/src/main/java/com/cloud/server/StatsCollector.java

@@ -1226,6 +1226,14 @@ protected void runInContext() {
 
                 Map<Object, Object> metrics = new HashMap<>();
                 for (HostVO host : hosts) {
+                    if (host.getHypervisorType() == HypervisorType.KVM && ManagementServerNode.getManagementServerId() != host.getManagementServerId()) {
+                        // When there are multiple Management Server nodes on the environment, all of them request stat collections for the same VM in different moments; with that,
+                        // the interval from "vm.stats.interval" is not respected. Also, the stats commands are routed to the Management Server connected to the Agent where the VM is running.
+                        // Furthermore, the number of stat entries on the DB scales with the number of Management Servers. Therefore, we only request the stat collections from
+                        // hosts connected to the Management Server, honoring the interval, presenting the correct data, and reducing the necessary storage to store the VMs stats.
+                        logger.debug("Skipping VM stat collection for [{}] as it is connected to another Management Server node [{}].", host, host.getManagementServerId());
+                        continue;
+                    }
                     Date timestamp = new Date();
                     Pair<Map<Long, VMInstanceVO>, Map<String, Long>> vmsAndMap = getVmMapForStatsForHost(host);
                     Map<Long, VMInstanceVO> vmMap = vmsAndMap.first();