Zen2: Move all mixed-version REST tests to Zen2 (#36398)

Moves all remaining (rolling-upgrade and mixed-version) REST tests to use Zen2. To avoid adding
extra configuration, it relies on Zen2 being set as the default discovery type. This required a few
smaller changes in other tests. I've removed AzureMinimumMasterNodesTests which tests Zen1
functionality and dates from a time where host providers were not configurable and each cloud
plugin had its own discovery.type, subclassing the ZenDiscovery class. I've also adapted a few tests
which were unnecessarily adding addTestZenDiscovery = false for the same legacy reasons. Finally,
this also moves the unconfigured-node-name REST test to Zen2, testing the auto-bootstrapping
functionality in development mode when no discovery configuration is provided.

Author: ywelsch

buildSrc/src/main/groovy/org/elasticsearch/gradle/test/ClusterConfiguration.groovy

@@ -76,6 +76,22 @@ class ClusterConfiguration {
         }
     }
 
+    /**
+     * Whether the initial_master_nodes setting should be automatically derived from the nodes
+     * in the cluster. Only takes effect if all nodes in the cluster understand this setting
+     * and the discovery type is not explicitly set.
+     */
+    @Input
+    boolean autoSetInitialMasterNodes = true
+
+    /**
+     * Whether the file-based discovery provider should be automatically setup based on
+     * the nodes in the cluster. Only takes effect if no other hosts provider is already
+     * configured.
+     */
+    @Input
+    boolean autoSetHostsProvider = true
+
     @Input
     String jvmArgs = "-Xms" + System.getProperty('tests.heap.size', '512m') +
         " " + "-Xmx" + System.getProperty('tests.heap.size', '512m') +

buildSrc/src/main/groovy/org/elasticsearch/gradle/test/ClusterFormationTasks.groovy

@@ -131,13 +131,15 @@ class ClusterFormationTasks {
             Object dependsOn
             if (node.nodeVersion.onOrAfter("6.5.0")) {
                 writeConfigSetup = { Map esConfig ->
-                    // Don't force discovery provider if one is set by the test cluster specs already
-                    if (esConfig.containsKey('discovery.zen.hosts_provider') == false) {
-                        esConfig['discovery.zen.hosts_provider'] = 'file'
+                    if (config.getAutoSetHostsProvider()) {
+                        // Don't force discovery provider if one is set by the test cluster specs already
+                        if (esConfig.containsKey('discovery.zen.hosts_provider') == false) {
+                            esConfig['discovery.zen.hosts_provider'] = 'file'
+                        }
+                        esConfig['discovery.zen.ping.unicast.hosts'] = []
                     }
-                    esConfig['discovery.zen.ping.unicast.hosts'] = []
-                    if (hasBwcNodes == false && esConfig['discovery.type'] == null) {
-                        esConfig['discovery.type'] = 'zen2'
+                    boolean supportsInitialMasterNodes = hasBwcNodes == false || config.bwcVersion.onOrAfter("7.0.0")
+                    if (esConfig['discovery.type'] == null && config.getAutoSetInitialMasterNodes() && supportsInitialMasterNodes) {
                         esConfig['cluster.initial_master_nodes'] = nodes.stream().map({ n ->
                             if (n.config.settings['node.name'] == null) {
                                 return "node-" + n.nodeNum

plugins/discovery-azure-classic/src/test/java/org/elasticsearch/cloud/azure/classic/AbstractAzureComputeServiceTestCase.java

@@ -84,11 +84,6 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singletonList(TestPlugin.class);
     }
 
-    @Override
-    protected boolean addTestZenDiscovery() {
-        return false;
-    }
-
     /**
      * Register an existing node as a Azure node, exposing its address and details htrough
      *

plugins/discovery-azure-classic/src/test/java/org/elasticsearch/discovery/azure/classic/AzureMinimumMasterNodesTests.java

@@ -69,9 +69,4 @@ protected Settings nodeSettings(int nodeOrdinal) {
     protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Arrays.asList(Ec2DiscoveryPlugin.class);
     }
-
-    @Override
-    protected boolean addTestZenDiscovery() {
-        return false;
-    }
 }

plugins/discovery-ec2/src/test/java/org/elasticsearch/discovery/ec2/AbstractAwsTestCase.java

@@ -33,7 +33,7 @@
  * starting.
  * This test requires AWS to run.
  */
-@ClusterScope(scope = Scope.TEST, numDataNodes = 0, numClientNodes = 0, transportClientRatio = 0.0, autoMinMasterNodes = false)
+@ClusterScope(scope = Scope.TEST, numDataNodes = 0, numClientNodes = 0, transportClientRatio = 0.0)
 public class Ec2DiscoveryUpdateSettingsTests extends AbstractAwsTestCase {
     public void testMinimumMasterNodesStart() {
         Settings nodeSettings = Settings.builder()

plugins/discovery-ec2/src/test/java/org/elasticsearch/discovery/ec2/Ec2DiscoveryUpdateSettingsTests.java

@@ -73,11 +73,6 @@ protected Settings nodeSettings(int nodeOrdinal) {
             .build();
     }
 
-    @Override
-    protected boolean addTestZenDiscovery() {
-        return false;
-    }
-
     public void testJoin() {
         // start master node
         final String masterNode = internalCluster().startMasterOnlyNode();

plugins/discovery-gce/src/test/java/org/elasticsearch/discovery/gce/GceDiscoverTests.java

@@ -78,13 +78,12 @@ for (Version version : bwcVersions.wireCompatible) {
       clusterName = 'rolling-upgrade'
       otherUnicastHostAddresses = { getOtherUnicastHostAddresses() }
       minimumMasterNodes = { 2 }
+      autoSetInitialMasterNodes = false
       /* Override the data directory so the new node always gets the node we
       * just stopped's data directory. */
       dataDir = { nodeNumber -> oldClusterTest.nodes[stopNode].dataDir }
       setting 'repositories.url.allowed_urls', 'http://snapshot.test*'
       setting 'node.name', "upgraded-node-${stopNode}"
-      // TODO: Move to Zen2 once we support rolling upgrade with Zen2
-      setting 'discovery.type', 'zen'
     }
   }
 

qa/rolling-upgrade/build.gradle

@@ -22,8 +22,10 @@ apply plugin: 'elasticsearch.rest-test'
 
 integTestCluster {
   setting 'node.name', null
-  // TODO: Run this using zen2, with no discovery configuration at all, demonstrating that the node forms a cluster on its own without help
-  setting 'discovery.type', 'zen'
+  // Run with no discovery configuration at all, demonstrating that a node in its
+  // "out-of-the-box" configuration can automatically bootstrap a cluster
+  autoSetInitialMasterNodes = false
+  autoSetHostsProvider = false
 }
 
 integTestRunner {

qa/unconfigured-node-name/build.gradle

@@ -103,6 +103,8 @@ public void start() {
                 transportService.getThreadPool().scheduleUnlessShuttingDown(unconfiguredBootstrapTimeout, Names.SAME, new Runnable() {
                     @Override
                     public void run() {
+                        // TODO: remove the following line once schedule method properly preserves thread context
+                        threadContext.markAsSystemContext();
                         final GetDiscoveredNodesRequest request = new GetDiscoveredNodesRequest();
                         logger.trace("sending {}", request);
                         transportService.sendRequest(transportService.getLocalNode(), GetDiscoveredNodesAction.NAME, request,
@@ -212,6 +214,8 @@ public void handleException(TransportException exp) {
                     transportService.getThreadPool().scheduleUnlessShuttingDown(TimeValue.timeValueSeconds(10), Names.SAME, new Runnable() {
                         @Override
                         public void run() {
+                            // TODO: remove the following line once schedule method properly preserves thread context
+                            transportService.getThreadPool().getThreadContext().markAsSystemContext();
                             awaitBootstrap(bootstrapConfiguration);
                         }