[ML] Include node name when native controller cannot start process (elastic#42225)

This adds the node name where we fail to start a process via the native
controller to facilitate debugging as otherwise it might not be known
to which node the job was allocated.

Author: dimitris-athanasiou

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/MachineLearning.java

@@ -437,7 +437,7 @@ public Collection<Object> createComponents(Client client, ClusterService cluster
         NormalizerProcessFactory normalizerProcessFactory;
         if (MachineLearningField.AUTODETECT_PROCESS.get(settings) && MachineLearningFeatureSet.isRunningOnMlPlatform(true)) {
             try {
-                NativeController nativeController = NativeControllerHolder.getNativeController(environment);
+                NativeController nativeController = NativeControllerHolder.getNativeController(clusterService.getNodeName(), environment);
                 if (nativeController == null) {
                     // This will only only happen when path.home is not set, which is disallowed in production
                     throw new ElasticsearchException("Failed to create native process controller for Machine Learning");

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/MachineLearningFeatureSet.java

@@ -79,7 +79,8 @@ public MachineLearningFeatureSet(Environment environment, ClusterService cluster
         if (enabled && XPackPlugin.transportClientMode(environment.settings()) == false) {
             try {
                 if (isRunningOnMlPlatform(true)) {
-                    NativeController nativeController = NativeControllerHolder.getNativeController(environment);
+                    NativeController nativeController = NativeControllerHolder.getNativeController(clusterService.getNodeName(),
+                        environment);
                     if (nativeController != null) {
                         nativeCodeInfo = nativeController.getNativeCodeInfo();
                     }

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/MlLifeCycleService.java

@@ -19,13 +19,15 @@
 public class MlLifeCycleService {
 
     private final Environment environment;
+    private final ClusterService clusterService;
     private final DatafeedManager datafeedManager;
     private final AutodetectProcessManager autodetectProcessManager;
     private final MlMemoryTracker memoryTracker;
 
     public MlLifeCycleService(Environment environment, ClusterService clusterService, DatafeedManager datafeedManager,
                               AutodetectProcessManager autodetectProcessManager, MlMemoryTracker memoryTracker) {
         this.environment = environment;
+        this.clusterService = clusterService;
         this.datafeedManager = datafeedManager;
         this.autodetectProcessManager = autodetectProcessManager;
         this.memoryTracker = memoryTracker;
@@ -46,7 +48,7 @@ public synchronized void stop() {
                 if (datafeedManager != null) {
                     datafeedManager.isolateAllDatafeedsOnThisNodeBeforeShutdown();
                 }
-                NativeController nativeController = NativeControllerHolder.getNativeController(environment);
+                NativeController nativeController = NativeControllerHolder.getNativeController(clusterService.getNodeName(), environment);
                 if (nativeController != null) {
                     // This kills autodetect processes WITHOUT closing the jobs, so they get reallocated.
                     if (autodetectProcessManager != null) {

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/process/NativeController.java

@@ -43,15 +43,17 @@ public class NativeController {
 
     public static final Map<String, Object> UNKNOWN_NATIVE_CODE_INFO = Map.of("version", "N/A", "build_hash", "N/A");
 
+    private final String localNodeName;
     private final CppLogMessageHandler cppLogHandler;
     private final OutputStream commandStream;
 
-    NativeController(Environment env, NamedPipeHelper namedPipeHelper) throws IOException {
+    NativeController(String localNodeName, Environment env, NamedPipeHelper namedPipeHelper) throws IOException {
         ProcessPipes processPipes = new ProcessPipes(env, namedPipeHelper, CONTROLLER, null,
                 true, true, false, false, false, false);
         processPipes.connectStreams(CONTROLLER_CONNECT_TIMEOUT);
-        cppLogHandler = new CppLogMessageHandler(null, processPipes.getLogStream().get());
-        commandStream = new BufferedOutputStream(processPipes.getCommandStream().get());
+        this.localNodeName = localNodeName;
+        this.cppLogHandler = new CppLogMessageHandler(null, processPipes.getLogStream().get());
+        this.commandStream = new BufferedOutputStream(processPipes.getCommandStream().get());
     }
 
     void tailLogsInThread() {
@@ -98,7 +100,8 @@ public void startProcess(List<String> command) throws IOException {
         }
 
         if (cppLogHandler.hasLogStreamEnded()) {
-            String msg = "Cannot start process [" + command.get(0) + "]: native controller process has stopped";
+            String msg = "Cannot start process [" + command.get(0) + "]: native controller process has stopped on node ["
+                + localNodeName + "]";
             LOGGER.error(msg);
             throw new ElasticsearchException(msg);
         }
@@ -124,7 +127,8 @@ public void killProcess(long pid) throws TimeoutException, IOException {
         }
 
         if (cppLogHandler.hasLogStreamEnded()) {
-            String msg = "Cannot kill process with PID [" + pid + "]: native controller process has stopped";
+            String msg = "Cannot kill process with PID [" + pid + "]: native controller process has stopped on node ["
+                + localNodeName + "]";
             LOGGER.error(msg);
             throw new ElasticsearchException(msg);
         }

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/process/NativeControllerHolder.java

@@ -32,12 +32,12 @@ private NativeControllerHolder() {
      *
      * Calls may throw an exception if initial connection to the C++ process fails.
      */
-    public static NativeController getNativeController(Environment environment) throws IOException {
+    public static NativeController getNativeController(String localNodeName, Environment environment) throws IOException {
 
         if (MachineLearningField.AUTODETECT_PROCESS.get(environment.settings())) {
             synchronized (lock) {
                 if (nativeController == null) {
-                    nativeController = new NativeController(environment, new NamedPipeHelper());
+                    nativeController = new NativeController(localNodeName, environment, new NamedPipeHelper());
                     nativeController.tailLogsInThread();
                 }
             }

x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/process/NativeControllerTests.java

@@ -30,6 +30,8 @@
 
 public class NativeControllerTests extends ESTestCase {
 
+    private static final String NODE_NAME = "native-controller-tests-node";
+
     private static final String TEST_MESSAGE = "{\"logger\":\"controller\",\"timestamp\":1478261151445,\"level\":\"INFO\",\"pid\":10211,"
             + "\"thread\":\"0x7fff7d2a8000\",\"message\":\"controller (64 bit): Version 6.0.0-alpha1-SNAPSHOT (Build a0d6ef8819418c) "
             + "Copyright (c) 2017 Elasticsearch BV\",\"method\":\"main\",\"file\":\"Main.cc\",\"line\":123}\n";
@@ -50,7 +52,7 @@ public void testStartProcessCommand() throws IOException {
         command.add("--arg2=42");
         command.add("--arg3=something with spaces");
 
-        NativeController nativeController = new NativeController(TestEnvironment.newEnvironment(settings), namedPipeHelper);
+        NativeController nativeController = new NativeController(NODE_NAME, TestEnvironment.newEnvironment(settings), namedPipeHelper);
         nativeController.startProcess(command);
 
         assertEquals("start\tmy_process\t--arg1\t--arg2=42\t--arg3=something with spaces\n",
@@ -65,7 +67,7 @@ public void testGetNativeCodeInfo() throws IOException, TimeoutException {
         ByteArrayOutputStream commandStream = new ByteArrayOutputStream();
         when(namedPipeHelper.openNamedPipeOutputStream(contains("command"), any(Duration.class))).thenReturn(commandStream);
 
-        NativeController nativeController = new NativeController(TestEnvironment.newEnvironment(settings), namedPipeHelper);
+        NativeController nativeController = new NativeController(NODE_NAME, TestEnvironment.newEnvironment(settings), namedPipeHelper);
         nativeController.tailLogsInThread();
         Map<String, Object> nativeCodeInfo = nativeController.getNativeCodeInfo();
 
@@ -83,15 +85,16 @@ public void testControllerDeath() throws Exception {
         ByteArrayOutputStream commandStream = new ByteArrayOutputStream();
         when(namedPipeHelper.openNamedPipeOutputStream(contains("command"), any(Duration.class))).thenReturn(commandStream);
 
-        NativeController nativeController = new NativeController(TestEnvironment.newEnvironment(settings), namedPipeHelper);
+        NativeController nativeController = new NativeController(NODE_NAME, TestEnvironment.newEnvironment(settings), namedPipeHelper);
         nativeController.tailLogsInThread();
 
         // As soon as the log stream ends startProcess should think the native controller has died
         assertBusy(() -> {
             ElasticsearchException e = expectThrows(ElasticsearchException.class,
                     () -> nativeController.startProcess(Collections.singletonList("my process")));
 
-            assertEquals("Cannot start process [my process]: native controller process has stopped", e.getMessage());
+            assertEquals("Cannot start process [my process]: native controller process has stopped on node " +
+                "[native-controller-tests-node]", e.getMessage());
         });
     }
 }