Replace internal usages of 'master' term in 'server/src/test' directory (#2520)

* Replace the non-inclusive terminology "master" with "cluster manager" in code comments, internal variable/method/class names, in `server/src/test` directory.
* Backwards compatibility is not impacted.
* Add a new unit test `testDeprecatedMasterNodeFilter()` to validate using `master:true` or `master:false` can filter the node in [Cluster Stats](https://opensearch.org/docs/latest/opensearch/rest-api/cluster-stats/) API, after the `master` role is deprecated in PR #2424

Signed-off-by: Tianli Feng <ftianli@amazon.com>

Author: Tianli Feng

server/src/internalClusterTest/java/org/opensearch/discovery/ClusterDisruptionIT.java

@@ -386,7 +386,7 @@ public void onFailure(Exception e) {
         );
 
         if (isolatedNode.equals(nonClusterManagerNode)) {
-            assertNoMaster(nonClusterManagerNode);
+            assertNoClusterManager(nonClusterManagerNode);
         } else {
             ensureStableCluster(2, nonClusterManagerNode);
         }

server/src/internalClusterTest/java/org/opensearch/discovery/ClusterManagerDisruptionIT.java

@@ -91,7 +91,7 @@ public void testClusterManagerNodeGCs() throws Exception {
 
         logger.info("waiting for nodes to de-elect cluster-manager [{}]", oldClusterManagerNode);
         for (String node : oldNonClusterManagerNodesSet) {
-            assertDifferentMaster(node, oldClusterManagerNode);
+            assertDifferentClusterManager(node, oldClusterManagerNode);
         }
 
         logger.info("waiting for nodes to elect a new cluster-manager");
@@ -107,7 +107,7 @@ public void testClusterManagerNodeGCs() throws Exception {
         // make sure all nodes agree on cluster-manager
         String newClusterManager = internalCluster().getMasterName();
         assertThat(newClusterManager, not(equalTo(oldClusterManagerNode)));
-        assertMaster(newClusterManager, nodes);
+        assertClusterManager(newClusterManager, nodes);
     }
 
     /**
@@ -137,7 +137,7 @@ public void testIsolateClusterManagerAndVerifyClusterStateConsensus() throws Exc
         ensureStableCluster(2, nonIsolatedNode);
 
         // make sure isolated need picks up on things.
-        assertNoMaster(isolatedNode, TimeValue.timeValueSeconds(40));
+        assertNoClusterManager(isolatedNode, TimeValue.timeValueSeconds(40));
 
         // restore isolation
         networkDisruption.stopDisrupting();
@@ -227,7 +227,7 @@ public void testVerifyApiBlocksDuringPartition() throws Exception {
         // continuously ping until network failures have been resolved. However
         // It may a take a bit before the node detects it has been cut off from the elected cluster-manager
         logger.info("waiting for isolated node [{}] to have no cluster-manager", isolatedNode);
-        assertNoMaster(isolatedNode, NoMasterBlockService.NO_MASTER_BLOCK_WRITES, TimeValue.timeValueSeconds(30));
+        assertNoClusterManager(isolatedNode, NoMasterBlockService.NO_MASTER_BLOCK_WRITES, TimeValue.timeValueSeconds(30));
 
         logger.info("wait until elected cluster-manager has been removed and a new 2 node cluster was from (via [{}])", isolatedNode);
         ensureStableCluster(2, nonIsolatedNode);
@@ -273,7 +273,7 @@ public void testVerifyApiBlocksDuringPartition() throws Exception {
         // continuously ping until network failures have been resolved. However
         // It may a take a bit before the node detects it has been cut off from the elected cluster-manager
         logger.info("waiting for isolated node [{}] to have no cluster-manager", isolatedNode);
-        assertNoMaster(isolatedNode, NoMasterBlockService.NO_MASTER_BLOCK_ALL, TimeValue.timeValueSeconds(30));
+        assertNoClusterManager(isolatedNode, NoMasterBlockService.NO_MASTER_BLOCK_ALL, TimeValue.timeValueSeconds(30));
 
         // make sure we have stable cluster & cross partition recoveries are canceled by the removal of the missing node
         // the unresponsive partition causes recoveries to only time out after 15m (default) and these will cause

server/src/internalClusterTest/java/org/opensearch/discovery/DiscoveryDisruptionIT.java

@@ -81,7 +81,7 @@ public void testClusterJoinDespiteOfPublishingIssues() throws Exception {
         );
         nonClusterManagerTransportService.addFailToSendNoConnectRule(clusterManagerTranspotService);
 
-        assertNoMaster(nonClusterManagerNode);
+        assertNoClusterManager(nonClusterManagerNode);
 
         logger.info(
             "blocking cluster state publishing from cluster-manager [{}] to non cluster-manager [{}]",
@@ -166,7 +166,7 @@ public void testElectClusterManagerWithLatestVersion() throws Exception {
         logger.info("--> forcing a complete election to make sure \"preferred\" cluster-manager is elected");
         isolateAllNodes.startDisrupting();
         for (String node : nodes) {
-            assertNoMaster(node);
+            assertNoClusterManager(node);
         }
         internalCluster().clearDisruptionScheme();
         ensureStableCluster(3);
@@ -194,7 +194,7 @@ public void testElectClusterManagerWithLatestVersion() throws Exception {
         logger.info("--> forcing a complete election again");
         isolateAllNodes.startDisrupting();
         for (String node : nodes) {
-            assertNoMaster(node);
+            assertNoClusterManager(node);
         }
 
         isolateAllNodes.stopDisrupting();
@@ -242,7 +242,7 @@ public void testNodeNotReachableFromClusterManager() throws Exception {
         ensureStableCluster(2, clusterManagerNode);
 
         logger.info("waiting for [{}] to have no cluster-manager", nonClusterManagerNode);
-        assertNoMaster(nonClusterManagerNode);
+        assertNoClusterManager(nonClusterManagerNode);
 
         logger.info("healing partition and checking cluster reforms");
         clusterManagerTransportService.clearAllRules();

server/src/test/java/org/opensearch/action/admin/cluster/configuration/TransportAddVotingConfigExclusionsActionTests.java

@@ -252,7 +252,7 @@ public void testWithdrawsVotesFromNodesMatchingWildcard() throws InterruptedExce
         assertWarnings(AddVotingConfigExclusionsRequest.DEPRECATION_MESSAGE);
     }
 
-    public void testWithdrawsVotesFromAllMasterEligibleNodes() throws InterruptedException {
+    public void testWithdrawsVotesFromAllClusterManagerEligibleNodes() throws InterruptedException {
         final CountDownLatch countDownLatch = new CountDownLatch(2);
 
         clusterStateObserver.waitForNextChange(new AdjustConfigurationForExclusions(countDownLatch));
@@ -349,14 +349,14 @@ public void testReturnsErrorIfNoMatchingNodeDescriptions() throws InterruptedExc
         assertWarnings(AddVotingConfigExclusionsRequest.DEPRECATION_MESSAGE);
     }
 
-    public void testOnlyMatchesMasterEligibleNodes() throws InterruptedException {
+    public void testOnlyMatchesClusterManagerEligibleNodes() throws InterruptedException {
         final CountDownLatch countDownLatch = new CountDownLatch(1);
         final SetOnce<TransportException> exceptionHolder = new SetOnce<>();
 
         transportService.sendRequest(
             localNode,
             AddVotingConfigExclusionsAction.NAME,
-            makeRequestWithNodeDescriptions("_all", "master:false"),
+            makeRequestWithNodeDescriptions("_all", "cluster_manager:false"),
             expectError(e -> {
                 exceptionHolder.set(e);
                 countDownLatch.countDown();
@@ -368,7 +368,7 @@ public void testOnlyMatchesMasterEligibleNodes() throws InterruptedException {
         assertThat(rootCause, instanceOf(IllegalArgumentException.class));
         assertThat(
             rootCause.getMessage(),
-            equalTo("add voting config exclusions request for [_all, master:false] matched no cluster-manager-eligible nodes")
+            equalTo("add voting config exclusions request for [_all, cluster_manager:false] matched no cluster-manager-eligible nodes")
         );
         assertWarnings(AddVotingConfigExclusionsRequest.DEPRECATION_MESSAGE);
     }

server/src/test/java/org/opensearch/action/admin/cluster/health/ClusterHealthResponsesTests.java

@@ -110,9 +110,9 @@ public void testClusterHealth() throws IOException {
         assertThat(clusterHealth.getActiveShardsPercent(), is(allOf(greaterThanOrEqualTo(0.0), lessThanOrEqualTo(100.0))));
     }
 
-    public void testClusterHealthVerifyMasterNodeDiscovery() throws IOException {
+    public void testClusterHealthVerifyClusterManagerNodeDiscovery() throws IOException {
         DiscoveryNode localNode = new DiscoveryNode("node", OpenSearchTestCase.buildNewFakeTransportAddress(), Version.CURRENT);
-        // set the node information to verify master_node discovery in ClusterHealthResponse
+        // set the node information to verify cluster_manager_node discovery in ClusterHealthResponse
         ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
             .nodes(DiscoveryNodes.builder().add(localNode).localNodeId(localNode.getId()).masterNodeId(localNode.getId()))
             .build();

server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/CancellableTasksTests.java

@@ -474,12 +474,12 @@ public void onFailure(Exception e) {
             for (int i = 1; i < testNodes.length; i++) {
                 discoveryNodes[i - 1] = testNodes[i].discoveryNode();
             }
-            DiscoveryNode master = discoveryNodes[0];
+            DiscoveryNode clusterManager = discoveryNodes[0];
             for (int i = 1; i < testNodes.length; i++) {
                 // Notify only nodes that should remain in the cluster
                 setState(
                     testNodes[i].clusterService,
-                    ClusterStateCreationUtils.state(testNodes[i].discoveryNode(), master, discoveryNodes)
+                    ClusterStateCreationUtils.state(testNodes[i].discoveryNode(), clusterManager, discoveryNodes)
                 );
             }
             if (randomBoolean()) {

server/src/test/java/org/opensearch/action/admin/cluster/node/tasks/TaskManagerTestCase.java

@@ -257,9 +257,9 @@ public static void connectNodes(TestNode... nodes) {
         for (int i = 0; i < nodes.length; i++) {
             discoveryNodes[i] = nodes[i].discoveryNode();
         }
-        DiscoveryNode master = discoveryNodes[0];
+        DiscoveryNode clusterManager = discoveryNodes[0];
         for (TestNode node : nodes) {
-            setState(node.clusterService, ClusterStateCreationUtils.state(node.discoveryNode(), master, discoveryNodes));
+            setState(node.clusterService, ClusterStateCreationUtils.state(node.discoveryNode(), clusterManager, discoveryNodes));
         }
         for (TestNode nodeA : nodes) {
             for (TestNode nodeB : nodes) {

server/src/test/java/org/opensearch/action/admin/cluster/reroute/ClusterRerouteRequestTests.java

@@ -161,7 +161,7 @@ public void testEqualsAndHashCode() {
             assertEquals(request, copy);
             assertEquals(request.hashCode(), copy.hashCode());
 
-            // Changing masterNodeTime makes requests not equal
+            // Changing clusterManagerNodeTimeout makes requests not equal
             copy.masterNodeTimeout(timeValueMillis(request.masterNodeTimeout().millis() + 1));
             assertNotEquals(request, copy);
             assertNotEquals(request.hashCode(), copy.hashCode());

server/src/test/java/org/opensearch/action/search/TransportMultiSearchActionTests.java

@@ -260,7 +260,7 @@ public void testDefaultMaxConcurrentSearches() {
         }
         builder.add(
             new DiscoveryNode(
-                "master",
+                "cluster_manager",
                 buildNewFakeTransportAddress(),
                 Collections.emptyMap(),
                 Collections.singleton(DiscoveryNodeRole.CLUSTER_MANAGER_ROLE),

server/src/test/java/org/opensearch/action/support/broadcast/node/TransportBroadcastByNodeActionTests.java

@@ -366,29 +366,29 @@ public void testOneRequestIsSentToEachNodeHoldingAShard() {
         }
     }
 
-    // simulate the master being removed from the cluster but before a new master is elected
-    // as such, the shards assigned to the master will still show up in the cluster state as assigned to a node but
-    // that node will not be in the local cluster state on any node that has detected the master as failing
+    // simulate the cluster-manager being removed from the cluster but before a new cluster-manager is elected
+    // as such, the shards assigned to the cluster-manager will still show up in the cluster state as assigned to a node but
+    // that node will not be in the local cluster state on any node that has detected the cluster-manager as failing
     // in this case, such a shard should be treated as unassigned
-    public void testRequestsAreNotSentToFailedMaster() {
+    public void testRequestsAreNotSentToFailedClusterManager() {
         Request request = new Request(new String[] { TEST_INDEX });
         PlainActionFuture<Response> listener = new PlainActionFuture<>();
 
-        DiscoveryNode masterNode = clusterService.state().nodes().getMasterNode();
+        DiscoveryNode clusterManagerNode = clusterService.state().nodes().getMasterNode();
         DiscoveryNodes.Builder builder = DiscoveryNodes.builder(clusterService.state().getNodes());
-        builder.remove(masterNode.getId());
+        builder.remove(clusterManagerNode.getId());
 
         setState(clusterService, ClusterState.builder(clusterService.state()).nodes(builder));
 
         action.new AsyncAction(null, request, listener).start();
 
         Map<String, List<CapturingTransport.CapturedRequest>> capturedRequests = transport.getCapturedRequestsByTargetNodeAndClear();
 
-        // the master should not be in the list of nodes that requests were sent to
+        // the cluster manager should not be in the list of nodes that requests were sent to
         ShardsIterator shardIt = clusterService.state().routingTable().allShards(new String[] { TEST_INDEX });
         Set<String> set = new HashSet<>();
         for (ShardRouting shard : shardIt) {
-            if (!shard.currentNodeId().equals(masterNode.getId())) {
+            if (!shard.currentNodeId().equals(clusterManagerNode.getId())) {
                 set.add(shard.currentNodeId());
             }
         }
@@ -399,7 +399,7 @@ public void testRequestsAreNotSentToFailedMaster() {
         // check requests were sent to the right nodes
         assertEquals(set, capturedRequests.keySet());
         for (Map.Entry<String, List<CapturingTransport.CapturedRequest>> entry : capturedRequests.entrySet()) {
-            // check one request was sent to each non-master node
+            // check one request was sent to each non-cluster-manager node
             assertEquals(1, entry.getValue().size());
         }
     }
@@ -456,13 +456,13 @@ public void testResultAggregation() throws ExecutionException, InterruptedExcept
         Request request = new Request(new String[] { TEST_INDEX });
         PlainActionFuture<Response> listener = new PlainActionFuture<>();
 
-        // simulate removing the master
-        final boolean simulateFailedMasterNode = rarely();
-        DiscoveryNode failedMasterNode = null;
-        if (simulateFailedMasterNode) {
-            failedMasterNode = clusterService.state().nodes().getMasterNode();
+        // simulate removing the cluster-manager
+        final boolean simulateFailedClusterManagerNode = rarely();
+        DiscoveryNode failedClusterManagerNode = null;
+        if (simulateFailedClusterManagerNode) {
+            failedClusterManagerNode = clusterService.state().nodes().getMasterNode();
             DiscoveryNodes.Builder builder = DiscoveryNodes.builder(clusterService.state().getNodes());
-            builder.remove(failedMasterNode.getId());
+            builder.remove(failedClusterManagerNode.getId());
             builder.masterNodeId(null);
 
             setState(clusterService, ClusterState.builder(clusterService.state()).nodes(builder));
@@ -511,8 +511,8 @@ public void testResultAggregation() throws ExecutionException, InterruptedExcept
                 transport.handleResponse(requestId, nodeResponse);
             }
         }
-        if (simulateFailedMasterNode) {
-            totalShards += map.get(failedMasterNode.getId()).size();
+        if (simulateFailedClusterManagerNode) {
+            totalShards += map.get(failedClusterManagerNode.getId()).size();
         }
 
         Response response = listener.get();