Deprecation check for No Master Block setting (#38383)

`discovery.zen.no_master_block` is deprecated in favor of
`cluster.no_master_block` in 7.0, but is a dynamic setting so we need
both node- and cluster-level checks for it.

Author: gwbrown

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/ClusterDeprecationChecks.java

@@ -18,6 +18,8 @@
 import java.util.Objects;
 import java.util.stream.Collectors;
 
+import static org.elasticsearch.discovery.DiscoverySettings.NO_MASTER_BLOCK_SETTING;
+
 public class ClusterDeprecationChecks {
 
     static DeprecationIssue checkShardLimit(ClusterState state) {
@@ -37,6 +39,18 @@ static DeprecationIssue checkShardLimit(ClusterState state) {
         return null;
     }
 
+    static DeprecationIssue checkNoMasterBlock(ClusterState state) {
+        if (state.metaData().settings().hasValue(NO_MASTER_BLOCK_SETTING.getKey())) {
+            return new DeprecationIssue(DeprecationIssue.Level.WARNING,
+                "Master block setting will be renamed",
+                "https://www.elastic.co/guide/en/elasticsearch/reference/master/breaking-changes-7.0.html" +
+                    "_new_name_for_literal_no_master_block_literal_setting",
+                "The setting discovery.zen.no_master_block will be renamed to cluster.no_master_block in 7.0. " +
+                    "Please unset discovery.zen.no_master_block and set cluster.no_master_block after upgrading to 7.0.");
+        }
+        return null;
+    }
+
     static DeprecationIssue checkClusterName(ClusterState state) {
         String clusterName = state.getClusterName().value();
         if (clusterName.contains(":")) {

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/DeprecationChecks.java

@@ -35,12 +35,14 @@ private DeprecationChecks() {
         Collections.unmodifiableList(Arrays.asList(
             ClusterDeprecationChecks::checkUserAgentPipelines,
             ClusterDeprecationChecks::checkShardLimit,
+            ClusterDeprecationChecks::checkNoMasterBlock,
             ClusterDeprecationChecks::checkClusterName
         ));
 
     static List<BiFunction<Settings, PluginsAndModules, DeprecationIssue>> NODE_SETTINGS_CHECKS =
         Collections.unmodifiableList(Arrays.asList(
             NodeDeprecationChecks::httpEnabledSettingRemoved,
+            NodeDeprecationChecks::noMasterBlockRenamed,
             NodeDeprecationChecks::auditLogPrefixSettingsCheck,
             NodeDeprecationChecks::indexThreadPoolCheck,
             NodeDeprecationChecks::bulkThreadPoolCheck,

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecks.java

@@ -24,6 +24,7 @@
 
 import static org.elasticsearch.discovery.DiscoveryModule.DISCOVERY_HOSTS_PROVIDER_SETTING;
 import static org.elasticsearch.discovery.DiscoveryModule.DISCOVERY_TYPE_SETTING;
+import static org.elasticsearch.discovery.DiscoverySettings.NO_MASTER_BLOCK_SETTING;
 import static org.elasticsearch.discovery.zen.SettingsBasedHostsProvider.DISCOVERY_ZEN_PING_UNICAST_HOSTS_SETTING;
 import static org.elasticsearch.xpack.core.XPackSettings.SECURITY_ENABLED;
 import static org.elasticsearch.xpack.core.XPackSettings.TRANSPORT_SSL_ENABLED;
@@ -44,6 +45,18 @@ static DeprecationIssue httpEnabledSettingRemoved(Settings nodeSettings, Plugins
         return null;
     }
 
+    static DeprecationIssue noMasterBlockRenamed(Settings nodeSettings, PluginsAndModules plugins) {
+        if (nodeSettings.hasValue(NO_MASTER_BLOCK_SETTING.getKey())) {
+            return new DeprecationIssue(DeprecationIssue.Level.CRITICAL,
+                "Master block setting renamed",
+                "https://www.elastic.co/guide/en/elasticsearch/reference/master/breaking-changes-7.0.html" +
+                    "_new_name_for_literal_no_master_block_literal_setting",
+                "The setting discovery.zen.no_master_block will be renamed to cluster.no_master_block in 7.0. " +
+                    "Please unset discovery.zen.no_master_block and set cluster.no_master_block after upgrading to 7.0.");
+        }
+        return null;
+    }
+
     static DeprecationIssue auditLogPrefixSettingsCheck(Settings nodeSettings, PluginsAndModules plugins) {
         if (nodeSettings.getByPrefix("xpack.security.audit.logfile.prefix").isEmpty() == false) {
             return new DeprecationIssue(DeprecationIssue.Level.CRITICAL,

x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/ClusterDeprecationChecksTests.java

@@ -24,6 +24,7 @@
 import java.util.List;
 
 import static java.util.Collections.singletonList;
+import static org.elasticsearch.discovery.DiscoverySettings.NO_MASTER_BLOCK_SETTING;
 import static org.elasticsearch.xpack.deprecation.DeprecationChecks.CLUSTER_SETTINGS_CHECKS;
 
 public class ClusterDeprecationChecksTests extends ESTestCase {
@@ -45,6 +46,25 @@ public void testCheckClusterName() {
         assertTrue(noIssues.isEmpty());
     }
 
+    public void testCheckNoMasterBlock() {
+        MetaData metaData = MetaData.builder()
+            .persistentSettings(Settings.builder()
+                .put(NO_MASTER_BLOCK_SETTING.getKey(), randomFrom("all", "write"))
+                .build())
+            .build();
+        ClusterState state = ClusterState.builder(new ClusterName("test"))
+            .metaData(metaData)
+            .build();
+        DeprecationIssue expected = new DeprecationIssue(DeprecationIssue.Level.WARNING,
+            "Master block setting will be renamed",
+            "https://www.elastic.co/guide/en/elasticsearch/reference/master/breaking-changes-7.0.html" +
+                "_new_name_for_literal_no_master_block_literal_setting",
+            "The setting discovery.zen.no_master_block will be renamed to cluster.no_master_block in 7.0. " +
+                "Please unset discovery.zen.no_master_block and set cluster.no_master_block after upgrading to 7.0.");
+        List<DeprecationIssue> issues = DeprecationChecks.filterChecks(CLUSTER_SETTINGS_CHECKS, c -> c.apply(state));
+        assertEquals(singletonList(expected), issues);
+    }
+
     public void testCheckShardLimit() {
         int shardsPerNode = randomIntBetween(2, 10000);
         int nodeCount = randomIntBetween(1, 10);

x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecksTests.java

@@ -30,6 +30,7 @@
 import static org.elasticsearch.cluster.ClusterName.CLUSTER_NAME_SETTING;
 import static org.elasticsearch.discovery.DiscoveryModule.DISCOVERY_HOSTS_PROVIDER_SETTING;
 import static org.elasticsearch.discovery.DiscoveryModule.DISCOVERY_TYPE_SETTING;
+import static org.elasticsearch.discovery.DiscoverySettings.NO_MASTER_BLOCK_SETTING;
 import static org.elasticsearch.node.Node.NODE_NAME_SETTING;
 import static org.elasticsearch.xpack.deprecation.DeprecationChecks.NODE_SETTINGS_CHECKS;
 
@@ -84,6 +85,17 @@ public void testHttpEnabledCheck() {
         assertSettingsAndIssue("http.enabled", Boolean.toString(randomBoolean()), expected);
     }
 
+    public void testNoMasterBlockRenamed() {
+        DeprecationIssue expected = new DeprecationIssue(DeprecationIssue.Level.CRITICAL,
+            "Master block setting renamed",
+            "https://www.elastic.co/guide/en/elasticsearch/reference/master/breaking-changes-7.0.html" +
+                "_new_name_for_literal_no_master_block_literal_setting",
+            "The setting discovery.zen.no_master_block will be renamed to cluster.no_master_block in 7.0. " +
+                "Please unset discovery.zen.no_master_block and set cluster.no_master_block after upgrading to 7.0.");
+
+        assertSettingsAndIssue(NO_MASTER_BLOCK_SETTING.getKey(), randomFrom("all", "write"), expected);
+    }
+
     public void testAuditLoggingPrefixSettingsCheck() {
         DeprecationIssue expected = new DeprecationIssue(DeprecationIssue.Level.CRITICAL,
             "Audit log node info settings renamed",