kvm: Agent should not check if remaining memory on host is sufficient (#2766)

When a Instance is (attempted to be) started in KVM Host the Agent
should not worry about the allocated memory on this host.

To make a proper judgement we need to take more into account:

- Memory Overcommit ratio
- Host reserved memory
- Host overcommit memory

The Management Server has all the information and the DeploymentPlanner
has to make the decision if a Instance should and can be started on a
Host, not the host itself.

Signed-off-by: Wido den Hollander <wido@widodh.nl>

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/LibvirtComputingResource.java

@@ -277,7 +277,6 @@ public class LibvirtComputingResource extends ServerResourceBase implements Serv
     protected int _rngRateBytes = 2048;
     private File _qemuSocketsPath;
     private final String _qemuGuestAgentSocketName = "org.qemu.guest_agent.0";
-    private long _totalMemory;
     protected WatchDogAction _watchDogAction = WatchDogAction.NONE;
     protected WatchDogModel _watchDogModel = WatchDogModel.I6300ESB;
 
@@ -2603,7 +2602,6 @@ public class LibvirtComputingResource extends ServerResourceBase implements Serv
     public StartupCommand[] initialize() {
 
         final List<Object> info = getHostInfo();
-        _totalMemory = (Long)info.get(2);
 
         final StartupRoutingCommand cmd =
                 new StartupRoutingCommand((Integer)info.get(0), (Long)info.get(1), (Long)info.get(2), (Long)info.get(4), (String)info.get(3), _hypervisorType,
@@ -3792,10 +3790,6 @@ public class LibvirtComputingResource extends ServerResourceBase implements Serv
         }
     }
 
-    public long getTotalMemory() {
-        return _totalMemory;
-    }
-
     public String getHostDistro() {
         return _hostDistro;
     }

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/wrapper/LibvirtStartCommandWrapper.java

@@ -24,7 +24,6 @@ import java.util.List;
 
 import org.apache.log4j.Logger;
 import org.libvirt.Connect;
-import org.libvirt.Domain;
 import org.libvirt.DomainInfo.DomainState;
 import org.libvirt.LibvirtException;
 
@@ -65,13 +64,6 @@ public final class LibvirtStartCommandWrapper extends CommandWrapper<StartComman
             vm = libvirtComputingResource.createVMFromSpec(vmSpec);
             conn = libvirtUtilitiesHelper.getConnectionByType(vm.getHvsType());
 
-            Long remainingMem = getFreeMemory(conn, libvirtComputingResource);
-            if (remainingMem == null){
-                return new StartAnswer(command, "failed to get free memory");
-            } else if (remainingMem < vmSpec.getMinRam()) {
-                return new StartAnswer(command, "Not enough memory on the host, remaining: " + remainingMem + ", asking: " + vmSpec.getMinRam());
-            }
-
             final NicTO[] nics = vmSpec.getNics();
 
             for (final NicTO nic : nics) {
@@ -160,22 +152,4 @@ public final class LibvirtStartCommandWrapper extends CommandWrapper<StartComman
             }
         }
     }
-
-    private Long getFreeMemory(final Connect conn, final LibvirtComputingResource libvirtComputingResource){
-        try {
-            long allocatedMem = 0;
-            int[] ids = conn.listDomains();
-            for(int id :ids) {
-                Domain dm = conn.domainLookupByID(id);
-                allocatedMem += dm.getMaxMemory() * 1024L;
-                s_logger.debug("vm: " + dm.getName() + " mem: " + dm.getMaxMemory() * 1024L);
-            }
-            Long remainingMem = libvirtComputingResource.getTotalMemory() - allocatedMem;
-            s_logger.debug("remaining mem" + remainingMem);
-            return remainingMem;
-        } catch (Exception e) {
-            s_logger.debug("failed to get free memory", e);
-            return null;
-        }
-    }
 }

plugins/hypervisors/kvm/src/test/java/com/cloud/hypervisor/kvm/resource/LibvirtComputingResourceTest.java

@@ -5038,7 +5038,6 @@ public class LibvirtComputingResourceTest {
             when(conn.domainLookupByID(vmId)).thenReturn(dm);
             when(dm.getMaxMemory()).thenReturn(1024L);
             when(dm.getName()).thenReturn(vmName);
-            when(libvirtComputingResource.getTotalMemory()).thenReturn(2048*1024L);
             doNothing().when(libvirtComputingResource).createVbd(conn, vmSpec, vmName, vmDef);
         } catch (final LibvirtException e) {
             fail(e.getMessage());