Special message for must join elected master in ClusterFormationHelper

Author: Andrey Ershov

server/src/main/java/org/elasticsearch/cluster/coordination/ClusterFormationFailureHelper.java

@@ -167,6 +167,12 @@ String getDescription() {
 
             assert clusterState.getLastCommittedConfiguration().isEmpty() == false;
 
+            if (clusterState.getLastCommittedConfiguration().equals(VotingConfiguration.MUST_JOIN_ELECTED_MASTER)) {
+                return String.format(Locale.ROOT,
+                        "master not discovered yet and this node was detached from its previous cluster, have discovered %s; %s",
+                        foundPeers, discoveryWillContinueDescription);
+            }
+
             final String quorumDescription;
             if (clusterState.getLastAcceptedConfiguration().equals(clusterState.getLastCommittedConfiguration())) {
                 quorumDescription = describeQuorum(clusterState.getLastAcceptedConfiguration());

server/src/test/java/org/elasticsearch/cluster/coordination/ClusterFormationFailureHelperTests.java

@@ -201,6 +201,42 @@ private static ClusterState state(DiscoveryNode localNode, String[] acceptedConf
                 .lastCommittedConfiguration(config(committedConfig)).build())).build();
     }
 
+
+    public void testDescriptionAfterDetachCluster() {
+        final DiscoveryNode localNode = new DiscoveryNode("local", buildNewFakeTransportAddress(), Version.CURRENT);
+
+        final ClusterState clusterState = state(localNode,
+                VotingConfiguration.MUST_JOIN_ELECTED_MASTER.getNodeIds().toArray(new String[0]));
+
+        assertThat(new ClusterFormationState(Settings.EMPTY, clusterState, emptyList(), emptyList(), 0L).getDescription(),
+                is("master not discovered yet and this node was detached from its previous cluster, " +
+                        "have discovered []; " +
+                        "discovery will continue using [] from hosts providers and [" + localNode +
+                        "] from last-known cluster state; node term 0, last-accepted version 0 in term 0"));
+
+        final TransportAddress otherAddress = buildNewFakeTransportAddress();
+        assertThat(new ClusterFormationState(Settings.EMPTY, clusterState, singletonList(otherAddress), emptyList(), 0L).getDescription(),
+                is("master not discovered yet and this node was detached from its previous cluster, " +
+                        "have discovered []; " +
+                        "discovery will continue using [" + otherAddress + "] from hosts providers and [" + localNode +
+                        "] from last-known cluster state; node term 0, last-accepted version 0 in term 0"));
+
+        final DiscoveryNode otherNode = new DiscoveryNode("otherNode", buildNewFakeTransportAddress(), Version.CURRENT);
+        assertThat(new ClusterFormationState(Settings.EMPTY, clusterState, emptyList(), singletonList(otherNode), 0L).getDescription(),
+                is("master not discovered yet and this node was detached from its previous cluster, " +
+                        "have discovered [" + otherNode + "]; " +
+                        "discovery will continue using [] from hosts providers and [" + localNode +
+                        "] from last-known cluster state; node term 0, last-accepted version 0 in term 0"));
+
+        final DiscoveryNode yetAnotherNode = new DiscoveryNode("yetAnotherNode", buildNewFakeTransportAddress(), Version.CURRENT);
+        assertThat(new ClusterFormationState(Settings.EMPTY, clusterState, emptyList(), singletonList(yetAnotherNode), 0L).getDescription(),
+                is("master not discovered yet and this node was detached from its previous cluster, " +
+                        "have discovered [" + yetAnotherNode + "]; " +
+                        "discovery will continue using [] from hosts providers and [" + localNode +
+                        "] from last-known cluster state; node term 0, last-accepted version 0 in term 0"));
+
+    }
+
     public void testDescriptionAfterBootstrapping() {
         final DiscoveryNode localNode = new DiscoveryNode("local", buildNewFakeTransportAddress(), Version.CURRENT);