[TEST] Print out the `tests.cluster` sys prop if available to be able to reproduce failures when using the external cluster

Relates to #5630

src/test/java/org/elasticsearch/test/ElasticsearchIntegrationTest.java

@@ -148,6 +148,11 @@ public abstract class ElasticsearchIntegrationTest extends ElasticsearchTestCase
      */
     public static final String TESTS_CLIENT_RATIO = "tests.client.ratio";
 
+    /**
+     * Key used to eventually switch to using an external cluster and provide its transport addresses
+     */
+    public static final String TESTS_CLUSTER = "tests.cluster";
+
     /**
      * Threshold at which indexing switches from frequently async to frequently bulk.
      */
@@ -190,7 +195,7 @@ public abstract class ElasticsearchIntegrationTest extends ElasticsearchTestCase
         // Initialize lazily. No need for volatiles/ CASs since each JVM runs at most one test
         // suite at any given moment.
         if (GLOBAL_CLUSTER == null) {
-            String cluster = System.getProperty("tests.cluster");
+            String cluster = System.getProperty(TESTS_CLUSTER);
             if (Strings.hasLength(cluster)) {
                 String[] stringAddresses = cluster.split(",");
                 TransportAddress[] transportAddresses = new TransportAddress[stringAddresses.length];

src/test/java/org/elasticsearch/test/ExternalTestCluster.java

@@ -24,6 +24,8 @@ import org.elasticsearch.action.admin.cluster.node.info.NodeInfo;
 import org.elasticsearch.action.admin.cluster.node.info.NodesInfoResponse;
 import org.elasticsearch.client.Client;
 import org.elasticsearch.client.transport.TransportClient;
+import org.elasticsearch.common.logging.ESLogger;
+import org.elasticsearch.common.logging.Loggers;
 import org.elasticsearch.common.settings.ImmutableSettings;
 import org.elasticsearch.common.transport.InetSocketTransportAddress;
 import org.elasticsearch.common.transport.TransportAddress;
@@ -38,6 +40,8 @@ import java.util.Iterator;
  */
 public final class ExternalTestCluster extends ImmutableTestCluster {
 
+    private final ESLogger logger = Loggers.getLogger(getClass());
+
     private final Client client;
 
     private final InetSocketAddress[] httpAddresses;
@@ -59,6 +63,7 @@ public final class ExternalTestCluster extends ImmutableTestCluster {
             }
         }
         this.dataNodes = dataNodes;
+        logger.info("Setup ExternalTestCluster [{}] made of [{}] nodes", nodeInfos.getClusterName().value(), size());
     }
 
     @Override

src/test/java/org/elasticsearch/test/junit/listeners/ReproduceInfoPrinter.java

@@ -32,6 +32,7 @@ import org.junit.runner.notification.Failure;
 import org.junit.runner.notification.RunListener;
 
 import static com.carrotsearch.randomizedtesting.SysGlobals.SYSPROP_ITERATIONS;
+import static org.elasticsearch.test.ElasticsearchIntegrationTest.TESTS_CLUSTER;
 
 /**
  * A {@link RunListener} that emits to {@link System#err} a string with command
@@ -114,7 +115,7 @@ public class ReproduceInfoPrinter extends RunListener {
         }
 
         public ReproduceErrorMessageBuilder appendESProperties() {
-            appendProperties("es.logger.level", "es.node.mode", "es.node.local", TestCluster.TESTS_ENABLE_MOCK_MODULES,
+            appendProperties("es.logger.level", "es.node.mode", "es.node.local", TESTS_CLUSTER, TestCluster.TESTS_ENABLE_MOCK_MODULES,
                     "tests.assertion.disabled", "tests.security.manager", "tests.nighly", "tests.jvms", "tests.client.ratio", "tests.heap.size");
             if (System.getProperty("tests.jvm.argline") != null && !System.getProperty("tests.jvm.argline").isEmpty()) {
                 appendOpt("tests.jvm.argline", "\"" + System.getProperty("tests.jvm.argline") + "\"");