PMM-14665 Skip nodes internal to a PMM deployment when adding a service

public/app/percona/add-instance/components/AddRemoteInstance/FormParts/NodesAgents/NodesAgents.test.tsx

@@ -7,6 +7,7 @@ import { InventoryService } from 'app/percona/inventory/Inventory.service';
 import {
   nodesMockMultipleAgentsNoPMMServer,
   nodesMock,
+  nodesMockHA,
   nodesMockOneAgentNoPMMServer,
 } from 'app/percona/inventory/__mocks__/Inventory.service';
 import * as NodesReducer from 'app/percona/shared/core/reducers/nodes/nodes';
@@ -55,6 +56,29 @@ describe('Nodes Agents:: ', () => {
     await waitFor(() => expect(screen.getByTestId('node')).toHaveTextContent(nodesMock[0].node_id));
   });
 
+  it('should not offer nodes internal to the PMM deployment', async () => {
+    jest.spyOn(InventoryService, 'getNodes').mockReturnValue(Promise.resolve({ nodes: nodesMockHA }));
+
+    setup();
+
+    await waitFor(() => expect(fetchNodesActionActionSpy).toHaveBeenCalled());
+
+    selectEvent.openMenu(screen.getByLabelText('Nodes'));
+
+    expect(screen.queryByText('pmm-pmm-ha-pg-db-instance1-qjjl-0')).not.toBeInTheDocument();
+    expect(screen.getByText('pmm-ha-0')).toBeInTheDocument();
+  });
+
+  it('should prefer a node other than a PMM Server one in an HA deployment', async () => {
+    jest.spyOn(InventoryService, 'getNodes').mockReturnValue(Promise.resolve({ nodes: nodesMockHA }));
+
+    setup();
+
+    await waitFor(() => expect(fetchNodesActionActionSpy).toHaveBeenCalled());
+
+    await waitFor(() => expect(screen.getByTestId('node')).toHaveTextContent('external-client-id'));
+  });
+
   it('should not pick any agent when the selected node is not pmm-server', async () => {
     jest
       .spyOn(InventoryService, 'getNodes')

public/app/percona/add-instance/components/AddRemoteInstance/FormParts/NodesAgents/NodesAgents.tsx

@@ -76,13 +76,17 @@ export const NodesAgents: FC<NodesAgentsProps> = ({ form }) => {
     if (nodesOptions.length === 0) {
       loadData();
     } else if (!selectedNode) {
-      // preselect pmm-server node
-      const pmmServerNode =
-        nodesOptions.find((node) => node.value === PMM_SERVER_NODE_ID) ||
+      // A deployment with more than one PMM Server node runs in HA mode, where the PMM Server
+      // pods are meant to stay free of monitoring workloads. Prefer any other node there,
+      // otherwise preselect the pmm-server node as usual.
+      const isHighlyAvailable = nodesOptions.filter((node) => node.isPMMServerNode).length > 1;
+      const preselectedNode =
+        (isHighlyAvailable ? nodesOptions.find((node) => !node.isPMMServerNode) : undefined) ??
+        nodesOptions.find((node) => node.value === PMM_SERVER_NODE_ID) ??
         nodesOptions.find((node) => node.isPMMServerNode);
 
-      if (pmmServerNode) {
-        setNodeAndAgent(pmmServerNode);
+      if (preselectedNode) {
+        setNodeAndAgent(preselectedNode);
       }
     }
     // eslint-disable-next-line react-hooks/exhaustive-deps

public/app/percona/inventory/Inventory.types.ts

@@ -160,6 +160,7 @@ export interface NodeDB {
   status: ServiceStatus;
   services?: ServiceNodeListDB[];
   is_pmm_server_node: boolean;
+  is_pmm_internal_node?: boolean;
 }
 
 export interface NodeListDBPayload {

public/app/percona/inventory/__mocks__/Inventory.service.ts

@@ -72,6 +72,45 @@ export const nodesMock = [
   },
 ];
 
+const haNodeMock = (nodeId: string, nodeName: string, isPMMServerNode: boolean, isInternalNode = false) => ({
+  node_id: nodeId,
+  node_type: 'generic',
+  node_name: nodeName,
+  is_pmm_server_node: isPMMServerNode,
+  is_pmm_internal_node: isInternalNode,
+  machine_id: '',
+  distro: '',
+  node_model: '',
+  container_id: '',
+  container_name: '',
+  address: '10.1.2.3',
+  region: '',
+  az: '',
+  custom_labels: {},
+  created_at: '2026-07-27T08:05:31.079300Z',
+  updated_at: '2026-07-27T08:05:31.079300Z',
+  status: ServiceStatus.UP,
+  agents: [
+    {
+      agent_id: `${nodeId}-pmm-agent`,
+      agent_type: AgentType.pmmAgent,
+      status: ServiceAgentStatus.RUNNING,
+      is_connected: true,
+    },
+  ],
+  services: [],
+});
+
+// Mimics a PMM HA deployment: three PMM Server Nodes, an external PMM Client and the Nodes of
+// PMM's own PostgreSQL cluster, which PMM Server reports as internal.
+export const nodesMockHA = [
+  haNodeMock('pmm-ha-0-id', 'pmm-ha-0', true),
+  haNodeMock('pmm-ha-1-id', 'pmm-ha-1', true),
+  haNodeMock('pmm-ha-2-id', 'pmm-ha-2', true),
+  haNodeMock('external-client-id', 'external-client', false),
+  haNodeMock('pg-db-instance1-id', 'pmm-pmm-ha-pg-db-instance1-qjjl-0', false, true),
+];
+
 export const nodesMockMultipleAgentsNoPMMServer = [
   {
     node_id: '324234234',

public/app/percona/shared/core/reducers/nodes/nodes.utils.ts

@@ -58,6 +58,9 @@ export const nodeFromDbMapper = (nodeFromDb: NodeDB[]): Node[] => {
 
 export const nodesOptionsMapper = (nodeFromDb: NodeDB[]): NodesOption[] =>
   nodeFromDb
+    // Nodes belonging to a PMM deployment's own infrastructure (e.g. the HA persistence layer)
+    // are dedicated and must not be delegated any monitoring workloads.
+    .filter((node) => !node.is_pmm_internal_node)
     .map((node) => {
       const agents = (node.agents || [])
         .filter((agent) => agent.agent_type === AgentType.pmmAgent)