Remove LongGCDisruption scheme (#115046) (#115443)

Long GC disruption relies on Thread.resume, which is removed in JDK 23.
Tests that use it predate more modern disruption tests. This commit
removes gc disruption and the master disruption tests. Note that tests
relying on this scheme have already not been running since JDK 20 first
deprecated Thread.resume.

Author: rjernst

server/src/internalClusterTest/java/org/elasticsearch/discovery/MasterDisruptionIT.java

@@ -21,66 +21,22 @@
 import org.elasticsearch.core.TimeValue;
 import org.elasticsearch.test.ESIntegTestCase;
 import org.elasticsearch.test.disruption.BlockMasterServiceOnMaster;
-import org.elasticsearch.test.disruption.IntermittentLongGCDisruption;
 import org.elasticsearch.test.disruption.NetworkDisruption;
 import org.elasticsearch.test.disruption.NetworkDisruption.TwoPartitions;
 import org.elasticsearch.test.disruption.ServiceDisruptionScheme;
-import org.elasticsearch.test.disruption.SingleNodeDisruption;
 import org.elasticsearch.xcontent.XContentType;
 
-import java.util.ArrayList;
-import java.util.HashSet;
 import java.util.List;
-import java.util.Set;
 
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.equalTo;
-import static org.hamcrest.Matchers.not;
 
 /**
  * Tests relating to the loss of the master.
  */
 @ESIntegTestCase.ClusterScope(scope = ESIntegTestCase.Scope.TEST, numDataNodes = 0)
 public class MasterDisruptionIT extends AbstractDisruptionTestCase {
 
-    /**
-     * Test that cluster recovers from a long GC on master that causes other nodes to elect a new one
-     */
-    public void testMasterNodeGCs() throws Exception {
-        List<String> nodes = startCluster(3);
-        // NOTE: this assume must happen after starting the cluster, so that cleanup will have something to cleanup.
-        assumeFalse("jdk20 removed thread suspend/resume", Runtime.version().feature() >= 20);
-
-        String oldMasterNode = internalCluster().getMasterName();
-        // a very long GC, but it's OK as we remove the disruption when it has had an effect
-        SingleNodeDisruption masterNodeDisruption = new IntermittentLongGCDisruption(random(), oldMasterNode, 100, 200, 30000, 60000);
-        internalCluster().setDisruptionScheme(masterNodeDisruption);
-        masterNodeDisruption.startDisrupting();
-
-        Set<String> oldNonMasterNodesSet = new HashSet<>(nodes);
-        oldNonMasterNodesSet.remove(oldMasterNode);
-
-        List<String> oldNonMasterNodes = new ArrayList<>(oldNonMasterNodesSet);
-
-        logger.info("waiting for nodes to de-elect master [{}]", oldMasterNode);
-        for (String node : oldNonMasterNodesSet) {
-            assertDifferentMaster(node, oldMasterNode);
-        }
-
-        logger.info("waiting for nodes to elect a new master");
-        ensureStableCluster(2, oldNonMasterNodes.get(0));
-
-        // restore GC
-        masterNodeDisruption.stopDisrupting();
-        final TimeValue waitTime = new TimeValue(DISRUPTION_HEALING_OVERHEAD.millis() + masterNodeDisruption.expectedTimeToHeal().millis());
-        ensureStableCluster(3, waitTime, false, oldNonMasterNodes.get(0));
-
-        // make sure all nodes agree on master
-        String newMaster = internalCluster().getMasterName();
-        assertThat(newMaster, not(equalTo(oldMasterNode)));
-        assertMaster(newMaster, nodes);
-    }
-
     /**
      * This test isolates the master from rest of the cluster, waits for a new master to be elected, restores the partition
      * and verifies that all node agree on the new cluster state