Ensure initial_master_nodes includes only master-eligible nodes

test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/DefaultSettingsProvider.java

@@ -65,8 +65,20 @@ public Map<String, String> get(LocalNodeSpec nodeSpec) {
         settings.put("action.destructive_requires_name", "false");
 
         // Setup cluster discovery
-        String nodeNames = nodeSpec.getCluster().getNodes().stream().map(LocalNodeSpec::getName).collect(Collectors.joining(","));
-        settings.put("cluster.initial_master_nodes", "[" + nodeNames + "]");
+        String masterEligibleNodes = nodeSpec.getCluster()
+            .getNodes()
+            .stream()
+            .filter(LocalNodeSpec::isMasterEligible)
+            .map(LocalNodeSpec::getName)
+            .collect(Collectors.joining(","));
+
+        if (masterEligibleNodes.isEmpty()) {
+            throw new IllegalStateException(
+                "Cannot start cluster '" + nodeSpec.getCluster().getName() + "' as it configured with no master-eligible nodes."
+            );
+        }
+
+        settings.put("cluster.initial_master_nodes", "[" + masterEligibleNodes + "]");
         settings.put("discovery.seed_providers", "file");
         settings.put("discovery.seed_hosts", "[]");
 

test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/LocalClusterSpec.java

@@ -170,9 +170,11 @@ public Map<String, String> getSystemProperties() {
         }
 
         public boolean isSecurityEnabled() {
-            return Boolean.parseBoolean(
-                resolveSettings().getOrDefault("xpack.security.enabled", getVersion().onOrAfter("8.0.0") ? "true" : "false")
-            );
+            return Boolean.parseBoolean(getSetting("xpack.security.enabled", getVersion().onOrAfter("8.0.0") ? "true" : "false"));
+        }
+
+        public boolean isMasterEligible() {
+            return getSetting("node.roles", "master").contains("master");
         }
 
         /**
@@ -204,7 +206,7 @@ public String getSetting(String setting, String defaultValue) {
          */
         public Map<String, String> resolveSettings() {
             Map<String, String> resolvedSettings = new HashMap<>();
-            settingsProviders.forEach(p -> resolvedSettings.putAll(p.get(this)));
+            settingsProviders.forEach(p -> resolvedSettings.putAll(p.get(getFilteredSpec(p))));
             resolvedSettings.putAll(settings);
             return resolvedSettings;
         }
@@ -226,5 +228,42 @@ public Map<String, String> resolveEnvironment() {
             resolvedEnvironment.putAll(environment);
             return resolvedEnvironment;
         }
+
+        /**
+         * Returns a new {@link LocalNodeSpec} without the given {@link SettingsProvider}. This is needed when resolving settings from a
+         * settings provider to avoid infinite recursion.
+         *
+         * @param filteredProvider the provider to omit from the new node spec
+         * @return a new local node spec
+         */
+        private LocalNodeSpec getFilteredSpec(SettingsProvider filteredProvider) {
+            LocalClusterSpec newCluster = new LocalClusterSpec(cluster.name, cluster.users, cluster.roleFiles);
+
+            List<LocalNodeSpec> nodeSpecs = cluster.nodes.stream()
+                .map(
+                    n -> new LocalNodeSpec(
+                        newCluster,
+                        n.name,
+                        n.version,
+                        n.settingsProviders.stream().filter(s -> s != filteredProvider).toList(),
+                        n.settings,
+                        n.environmentProviders,
+                        n.environment,
+                        n.modules,
+                        n.plugins,
+                        n.distributionType,
+                        n.features,
+                        n.keystoreSettings,
+                        n.keystorePassword,
+                        n.extraConfigFiles,
+                        n.systemProperties
+                    )
+                )
+                .toList();
+
+            newCluster.setNodes(nodeSpecs);
+
+            return nodeSpecs.stream().filter(n -> n.getName().equals(this.getName())).findFirst().get();
+        }
     }
 }