Don't allow adding of existing host to another zone, pod or cluster

server/src/main/java/com/cloud/resource/ResourceManagerImpl.java

@@ -31,6 +31,7 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Random;
 import java.util.stream.Collectors;
 
@@ -2281,6 +2282,27 @@ private HostVO getNewHost(StartupCommand[] startupCommands) {
         return null;
     }
 
+    protected void validateExistingHostLocationImmutable(final HostVO host, final boolean newHost,
+            final long dcId, final Long podId, final Long clusterId, final StartupCommand startup) {
+        if (newHost || host == null || host.getType() != Host.Type.Routing) {
+            return;
+        }
+        final Long existingDcId = host.getDataCenterId();
+        final Long existingPodId = host.getPodId();
+        final Long existingClusterId = host.getClusterId();
+        if (existingDcId == null || existingPodId == null || existingClusterId == null) {
+            return;
+        }
+        if (existingDcId == dcId && Objects.equals(existingPodId, podId) && Objects.equals(existingClusterId, clusterId)) {
+            return;
+        }
+        final String identity = host.getUuid() != null ? host.getUuid() : host.getGuid();
+        final String ip = startup != null ? startup.getPrivateIpAddress() : "unknown";
+        throw new InvalidParameterValueException(String.format(
+                "Host %s (ip: %s) is already registered in [zone: %d, pod: %d, cluster: %d] and cannot be re-added or reconnected with [zone: %d, pod: %s, cluster: %s]. Zone, pod and cluster of an existing host are immutable.",
+                identity, ip, existingDcId, existingPodId, existingClusterId, dcId, podId, clusterId));
+    }
+
     protected HostVO createHostVO(final StartupCommand[] cmds, final ServerResource resource, final Map<String, String> details, List<String> hostTags,
             final ResourceStateAdapter.Event stateEvent) {
         boolean newHost = false;
@@ -2356,6 +2378,8 @@ protected HostVO createHostVO(final StartupCommand[] cmds, final ServerResource
             }
         }
 
+        validateExistingHostLocationImmutable(host, newHost, dcId, podId, clusterId, startup);
+
         host.setDataCenterId(dc.getId());
         host.setPodId(podId);
         host.setClusterId(clusterId);

server/src/test/java/com/cloud/resource/ResourceManagerImplTest.java

@@ -18,6 +18,7 @@
 package com.cloud.resource;
 
 import com.cloud.agent.AgentManager;
+import com.cloud.agent.api.StartupCommand;
 import com.cloud.agent.api.GetVncPortAnswer;
 import com.cloud.agent.api.GetVncPortCommand;
 import com.cloud.capacity.dao.CapacityDao;
@@ -335,6 +336,74 @@ public void testGetHostCredentialsMissingParameter() {
         resourceManager.getHostCredentials(host);
     }
 
+    private HostVO mockExistingRoutingHost(long dcId, Long podId, Long clusterId) {
+        HostVO existing = Mockito.mock(HostVO.class);
+        when(existing.getType()).thenReturn(Host.Type.Routing);
+        when(existing.getDataCenterId()).thenReturn(dcId);
+        when(existing.getPodId()).thenReturn(podId);
+        when(existing.getClusterId()).thenReturn(clusterId);
+        when(existing.getUuid()).thenReturn("host-uuid");
+        return existing;
+    }
+
+    @Test(expected = InvalidParameterValueException.class)
+    public void testValidateExistingHostLocationImmutableRejectsZoneChange() {
+        HostVO existing = mockExistingRoutingHost(1L, 10L, 100L);
+        StartupCommand startup = Mockito.mock(StartupCommand.class);
+        when(startup.getPrivateIpAddress()).thenReturn("10.10.10.10");
+        resourceManager.validateExistingHostLocationImmutable(existing, false, 2L, 10L, 100L, startup);
+    }
+
+    @Test(expected = InvalidParameterValueException.class)
+    public void testValidateExistingHostLocationImmutableRejectsPodChange() {
+        HostVO existing = mockExistingRoutingHost(1L, 10L, 100L);
+        StartupCommand startup = Mockito.mock(StartupCommand.class);
+        when(startup.getPrivateIpAddress()).thenReturn("10.10.10.10");
+        resourceManager.validateExistingHostLocationImmutable(existing, false, 1L, 11L, 100L, startup);
+    }
+
+    @Test(expected = InvalidParameterValueException.class)
+    public void testValidateExistingHostLocationImmutableRejectsClusterChange() {
+        HostVO existing = mockExistingRoutingHost(1L, 10L, 100L);
+        StartupCommand startup = Mockito.mock(StartupCommand.class);
+        when(startup.getPrivateIpAddress()).thenReturn("10.10.10.10");
+        resourceManager.validateExistingHostLocationImmutable(existing, false, 1L, 10L, 101L, startup);
+    }
+
+    @Test
+    public void testValidateExistingHostLocationImmutableAllowsSameTupleReconnect() {
+        HostVO existing = mockExistingRoutingHost(1L, 10L, 100L);
+        resourceManager.validateExistingHostLocationImmutable(existing, false, 1L, 10L, 100L, null);
+    }
+
+    @Test
+    public void testValidateExistingHostLocationImmutableAllowsNewHost() {
+        HostVO existing = mockExistingRoutingHost(2L, 20L, 200L);
+        resourceManager.validateExistingHostLocationImmutable(existing, true, 1L, 10L, 100L, null);
+    }
+
+    @Test
+    public void testValidateExistingHostLocationImmutableSkipsNonRoutingHost() {
+        HostVO existing = Mockito.mock(HostVO.class);
+        when(existing.getType()).thenReturn(Host.Type.SecondaryStorageVM);
+        resourceManager.validateExistingHostLocationImmutable(existing, false, 1L, 10L, 100L, null);
+    }
+
+    @Test
+    public void testValidateExistingHostLocationImmutableSkipsPartialLocationRow() {
+        HostVO existing = Mockito.mock(HostVO.class);
+        when(existing.getType()).thenReturn(Host.Type.Routing);
+        when(existing.getDataCenterId()).thenReturn(1L);
+        when(existing.getPodId()).thenReturn(null);
+        when(existing.getClusterId()).thenReturn(null);
+        resourceManager.validateExistingHostLocationImmutable(existing, false, 2L, 10L, 100L, null);
+    }
+
+    @Test
+    public void testValidateExistingHostLocationImmutableSkipsNullExistingHost() {
+        resourceManager.validateExistingHostLocationImmutable(null, false, 2L, 10L, 100L, null);
+    }
+
     @Test
     public void testGetHostCredentials() {
         Ternary<String, String, String> credentials = resourceManager.getHostCredentials(host);