[KVM] Add watchdog model none to disable use of watchdogs on KVM agent (#10203)

agent/conf/agent.properties

@@ -286,6 +286,7 @@ hypervisor.type=kvm
 
 # The model of Watchdog timer to present to the Guest.
 # For all models refer to the libvirt documentation.
+# PLEASE NOTE: to disable the watchdogs definitions, use value: none
 #vm.watchdog.model=i6300esb
 
 # Action to take when the Guest/Instance is no longer notifying the Watchdog timer.

agent/src/main/java/com/cloud/agent/properties/AgentProperties.java

@@ -516,6 +516,7 @@ public class AgentProperties{
     /**
      * The model of Watchdog timer to present to the Guest.<br>
      * For all models refer to the libvirt documentation.<br>
+     * PLEASE NOTE: to disable the watchdogs definitions, use value: none
      * Data type: String.<br>
      * Default value: <code>i6300esb</code>
      */

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

@@ -2293,7 +2293,7 @@ public class LibvirtVMDef {
 
     public static class WatchDogDef {
         enum WatchDogModel {
-            I6300ESB("i6300esb"), IB700("ib700"), DIAG288("diag288"), ITCO("itco");
+            I6300ESB("i6300esb"), IB700("ib700"), DIAG288("diag288"), ITCO("itco"), NONE("none");
             String model;
 
             WatchDogModel(String model) {
@@ -2346,6 +2346,10 @@ public class LibvirtVMDef {
 
         @Override
         public String toString() {
+            if (WatchDogModel.NONE == model) {
+                // Do not add watchodogs when the model is set to none
+                return "";
+            }
             StringBuilder wacthDogBuilder = new StringBuilder();
             wacthDogBuilder.append("<watchdog model='" + model + "' action='" + action + "'/>\n");
             return wacthDogBuilder.toString();

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

@@ -31,6 +31,7 @@ import com.cloud.hypervisor.kvm.resource.LibvirtVMDef.DiskDef;
 import com.cloud.hypervisor.kvm.resource.LibvirtVMDef.MemBalloonDef;
 import com.cloud.hypervisor.kvm.resource.LibvirtVMDef.SCSIDef;
 import org.apache.cloudstack.utils.qemu.QemuObject;
+import org.apache.commons.lang3.StringUtils;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.junit.MockitoJUnitRunner;
@@ -537,6 +538,16 @@ public class LibvirtVMDefTest extends TestCase {
         assertEquals(action, def.getAction());
     }
 
+    @Test
+    public void testWatchDofDefNone() {
+        LibvirtVMDef.WatchDogDef.WatchDogModel model = LibvirtVMDef.WatchDogDef.WatchDogModel.NONE;
+        LibvirtVMDef.WatchDogDef.WatchDogAction action = LibvirtVMDef.WatchDogDef.WatchDogAction.RESET;
+        LibvirtVMDef.WatchDogDef def = new LibvirtVMDef.WatchDogDef(action, model);
+        String result = def.toString();
+        assertNotNull(result);
+        assertTrue(StringUtils.isBlank(result));
+    }
+
     @Test
     public void testSCSIDef() {
         SCSIDef def = new SCSIDef((short)0, 0, 0, 9, 0, 4);