**Build scan:**
https://gradle-enterprise.elastic.co/s/pz33y5ym4lq44/tests/:server:internalClusterTest/org.elasticsearch.readiness.ReadinessClusterIT/testReadyAfterCorrectFileSettings

**Reproduction line:**
```
gradlew ':server:internalClusterTest' --tests "org.elasticsearch.readiness.ReadinessClusterIT.testReadyAfterCorrectFileSettings" -Dtests.seed=FFB71983A07E7720 -Dtests.locale=it-IT -Dtests.timezone=Indian/Maldives -Druntime.java=19
```

**Applicable branches:**
8.6

**Reproduces locally?:**
Didn't try

**Failure history:**
https://gradle-enterprise.elastic.co/scans/tests?tests.container=org.elasticsearch.readiness.ReadinessClusterIT&tests.test=testReadyAfterCorrectFileSettings

**Failure excerpt:**
```
java.lang.NullPointerException: Cannot invoke "org.elasticsearch.common.transport.BoundTransportAddress.publishAddress()" because the return value of "org.elasticsearch.readiness.ReadinessService.boundAddress()" is null

  at __randomizedtesting.SeedInfo.seed([FFB71983A07E7720:2E556980FF8889E8]:0)
  at org.elasticsearch.test.readiness.ReadinessClientProbe.tcpReadinessProbeTrue(ReadinessClientProbe.java:37)
  at org.elasticsearch.readiness.ReadinessClusterIT.testReadyAfterCorrectFileSettings(ReadinessClusterIT.java:327)
  at jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
  at java.lang.reflect.Method.invoke(Method.java:578)
  at com.carrotsearch.randomizedtesting.RandomizedRunner.invoke(RandomizedRunner.java:1758)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$8.evaluate(RandomizedRunner.java:946)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$9.evaluate(RandomizedRunner.java:982)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$10.evaluate(RandomizedRunner.java:996)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at org.apache.lucene.tests.util.TestRuleSetupTeardownChained$1.evaluate(TestRuleSetupTeardownChained.java:44)
  at org.apache.lucene.tests.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:43)
  at org.apache.lucene.tests.util.TestRuleThreadAndTestName$1.evaluate(TestRuleThreadAndTestName.java:45)
  at org.apache.lucene.tests.util.TestRuleIgnoreAfterMaxFailures$1.evaluate(TestRuleIgnoreAfterMaxFailures.java:60)
  at org.apache.lucene.tests.util.TestRuleMarkFailure$1.evaluate(TestRuleMarkFailure.java:44)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl$StatementRunner.run(ThreadLeakControl.java:390)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl.forkTimeoutingTask(ThreadLeakControl.java:843)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl$3.evaluate(ThreadLeakControl.java:490)
  at com.carrotsearch.randomizedtesting.RandomizedRunner.runSingleTest(RandomizedRunner.java:955)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$5.evaluate(RandomizedRunner.java:840)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$6.evaluate(RandomizedRunner.java:891)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$7.evaluate(RandomizedRunner.java:902)
  at org.apache.lucene.tests.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:43)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at org.apache.lucene.tests.util.TestRuleStoreClassName$1.evaluate(TestRuleStoreClassName.java:38)
  at com.carrotsearch.randomizedtesting.rules.NoShadowingOrOverridesOnMethodsRule$1.evaluate(NoShadowingOrOverridesOnMethodsRule.java:40)
  at com.carrotsearch.randomizedtesting.rules.NoShadowingOrOverridesOnMethodsRule$1.evaluate(NoShadowingOrOverridesOnMethodsRule.java:40)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at org.apache.lucene.tests.util.TestRuleAssertionsRequired$1.evaluate(TestRuleAssertionsRequired.java:53)
  at org.apache.lucene.tests.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:43)
  at org.apache.lucene.tests.util.TestRuleMarkFailure$1.evaluate(TestRuleMarkFailure.java:44)
  at org.apache.lucene.tests.util.TestRuleIgnoreAfterMaxFailures$1.evaluate(TestRuleIgnoreAfterMaxFailures.java:60)
  at org.apache.lucene.tests.util.TestRuleIgnoreTestSuites$1.evaluate(TestRuleIgnoreTestSuites.java:47)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl$StatementRunner.run(ThreadLeakControl.java:390)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl.lambda$forkTimeoutingTask$0(ThreadLeakControl.java:850)
  at java.lang.Thread.run(Thread.java:1589)

```
server/src/internalClusterTest/java/org/elasticsearch/readiness/ReadinessClusterIT.java
import org.elasticsearch.discovery.MasterNotDiscoveredException;
import org.elasticsearch.reservedstate.action.ReservedClusterSettingsAction;
import org.elasticsearch.reservedstate.service.FileSettingsService;
import org.elasticsearch.test.ESIntegTestCase;
import org.elasticsearch.test.ESIntegTestCase.ClusterScope;
import org.elasticsearch.test.InternalTestCluster;
import org.elasticsearch.test.readiness.ReadinessClientProbe;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
import static org.elasticsearch.node.Node.INITIAL_STATE_TIMEOUT_SETTING;
import static org.elasticsearch.test.NodeRoles.dataOnlyNode;
import static org.elasticsearch.test.NodeRoles.masterNode;
import static org.elasticsearch.test.NodeRoles.nonDataNode;
import static org.hamcrest.Matchers.allOf;
import static org.hamcrest.Matchers.containsString;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.hasSize;
import static org.hamcrest.Matchers.notNullValue;
@ClusterScope(scope = ESIntegTestCase.Scope.TEST, numDataNodes = 0, autoManageMasterNodes = false)
public class ReadinessClusterIT extends ESIntegTestCase implements ReadinessClientProbe {
    private static AtomicLong versionCounter = new AtomicLong(1);
    private static String testErrorJSON = """
        {
             "metadata": {