Make xpack.ilm.enabled setting a no-op (#55592)

docs/reference/migration/migrate_7_0/settings.asciidoc

@@ -292,11 +292,22 @@ greater than `Integer.MAX_VALUE`.  This leniency has been removed.
 [float]
 ==== Option to disable basic license features is deprecated
 
-In Elasticsearch 7.8.0, the following settings have been deprecated:
+In Elasticsearch 7.8.0, the following settings no longer have any effect, and
+have been deprecated:
+
+* `xpack.ilm.enabled`
+
+In other words, even if `xpack.ilm.enabled` is set to `false`, the ILM APIs
+will be available.
+
+If you have disabled ILM so that you can use another tool to manage Watcher
+indices, the newly introduced `xpack.watcher.use_ilm_index_management` setting
+may be set to false.
+
+Additionally, the following settings have been deprecated:
 
 * `xpack.enrich.enabled`
 * `xpack.flattened.enabled`
-* `xpack.ilm.enabled`
 * `xpack.monitoring.enabled`
 * `xpack.rollup.enabled`
 * `xpack.slm.enabled`
@@ -305,4 +316,4 @@ In Elasticsearch 7.8.0, the following settings have been deprecated:
 * `xpack.vectors.enabled`
 
 In future releases, it will not be possible to disable the APIs for Enrichment,
-Flattened mappings, ILM, Monitoring, Rollup, SLM, SQL, Transforms, and Vectors.
+Flattened mappings, Monitoring, Rollup, SLM, SQL, Transforms, and Vectors.

docs/reference/settings/ilm-settings.asciidoc

@@ -7,9 +7,8 @@ These are the settings available for configuring Index Lifecycle Management
 ==== Cluster level settings
 
 `xpack.ilm.enabled`::
-deprecated:[7.8.0,Basic License features should always be enabled] +
-Whether ILM is enabled or disabled, setting this to `false` disables any ILM
-REST API endpoints and functionality. Defaults to `true`.
+deprecated:[7.8.0,Basic License features are always enabled] +
+This deprecated setting has no effect and will be removed in Elasticsearch 8.0.
 
 `indices.lifecycle.poll_interval`::
 (<<time-units, time units>>) How often {ilm} checks for indices that meet policy

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/XPackSettings.java

@@ -93,7 +93,10 @@ private XPackSettings() {
 
     /**
      * Setting for enabling or disabling the index lifecycle extension. Defaults to true.
+     * <p>
+     * This setting is now a no-op: setting it to false is permitted, but does nothing.
      */
+    @Deprecated // since 7.8.0
     public static final Setting<Boolean> INDEX_LIFECYCLE_ENABLED = Setting.boolSetting("xpack.ilm.enabled", true,
         Property.NodeScope, Property.Deprecated);
 

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ilm/IndexLifecycleFeatureSetUsage.java

@@ -49,12 +49,12 @@ public void writeTo(StreamOutput out) throws IOException {
         }
     }
 
-    public IndexLifecycleFeatureSetUsage(boolean available, boolean enabled) {
-        this(available, enabled, null);
+    public IndexLifecycleFeatureSetUsage(boolean available) {
+        this(available, null);
     }
 
-    public IndexLifecycleFeatureSetUsage(boolean available, boolean enabled, List<PolicyStats> policyStats) {
-        super(XPackField.INDEX_LIFECYCLE, available, enabled);
+    public IndexLifecycleFeatureSetUsage(boolean available, List<PolicyStats> policyStats) {
+        super(XPackField.INDEX_LIFECYCLE, available, true);
         this.policyStats = policyStats;
     }
 

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/template/IndexTemplateRegistry.java

@@ -26,7 +26,6 @@
 import org.elasticsearch.gateway.GatewayService;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.xpack.core.XPackClient;
-import org.elasticsearch.xpack.core.XPackSettings;
 import org.elasticsearch.xpack.core.ilm.IndexLifecycleMetadata;
 import org.elasticsearch.xpack.core.ilm.LifecyclePolicy;
 import org.elasticsearch.xpack.core.ilm.action.PutLifecycleAction;
@@ -203,29 +202,26 @@ public void onFailure(Exception e) {
     }
 
     private void addIndexLifecyclePoliciesIfMissing(ClusterState state) {
-        boolean ilmSupported = XPackSettings.INDEX_LIFECYCLE_ENABLED.get(settings);
 
-        if (ilmSupported) {
-            Optional<IndexLifecycleMetadata> maybeMeta = Optional.ofNullable(state.metadata().custom(IndexLifecycleMetadata.TYPE));
-            List<LifecyclePolicy> policies = getPolicyConfigs().stream()
-                .map(policyConfig -> policyConfig.load(xContentRegistry))
-                .collect(Collectors.toList());
+        Optional<IndexLifecycleMetadata> maybeMeta = Optional.ofNullable(state.metadata().custom(IndexLifecycleMetadata.TYPE));
+        List<LifecyclePolicy> policies = getPolicyConfigs().stream()
+            .map(policyConfig -> policyConfig.load(xContentRegistry))
+            .collect(Collectors.toList());
 
-            for (LifecyclePolicy policy : policies) {
-                final AtomicBoolean creationCheck = policyCreationsInProgress.computeIfAbsent(policy.getName(),
-                    key -> new AtomicBoolean(false));
-                if (creationCheck.compareAndSet(false, true)) {
-                    final boolean policyNeedsToBeCreated = maybeMeta
-                        .flatMap(ilmMeta -> Optional.ofNullable(ilmMeta.getPolicies().get(policy.getName())))
-                        .isPresent() == false;
-                    if (policyNeedsToBeCreated) {
-                        logger.debug("adding lifecycle policy [{}] for [{}], because it doesn't exist", policy.getName(), getOrigin());
-                        putPolicy(policy, creationCheck);
-                    } else {
-                        logger.trace("not adding lifecycle policy [{}] for [{}], because it already exists",
-                            policy.getName(), getOrigin());
-                        creationCheck.set(false);
-                    }
+        for (LifecyclePolicy policy : policies) {
+            final AtomicBoolean creationCheck = policyCreationsInProgress.computeIfAbsent(policy.getName(),
+                key -> new AtomicBoolean(false));
+            if (creationCheck.compareAndSet(false, true)) {
+                final boolean policyNeedsToBeCreated = maybeMeta
+                    .flatMap(ilmMeta -> Optional.ofNullable(ilmMeta.getPolicies().get(policy.getName())))
+                    .isPresent() == false;
+                if (policyNeedsToBeCreated) {
+                    logger.debug("adding lifecycle policy [{}] for [{}], because it doesn't exist", policy.getName(), getOrigin());
+                    putPolicy(policy, creationCheck);
+                } else {
+                    logger.trace("not adding lifecycle policy [{}] for [{}], because it already exists",
+                        policy.getName(), getOrigin());
+                    creationCheck.set(false);
                 }
             }
         }

x-pack/plugin/core/src/main/resources/org/elasticsearch/xpack/core/ml/anomalydetection/state_index_template.json

@@ -8,8 +8,9 @@
     "index" : {
       "auto_expand_replicas" : "0-1",
       "hidden": true
-    }
-    ${xpack.ml.index.lifecycle.settings}
+    },
+    "index.lifecycle.name": "${xpack.ml.index.lifecycle.name}",
+    "index.lifecycle.rollover_alias": "${xpack.ml.index.lifecycle.rollover_alias}"
   },
   "mappings" : {
     "_doc": {

x-pack/plugin/core/src/main/resources/org/elasticsearch/xpack/core/ml/stats_index_template.json

@@ -9,8 +9,9 @@
       "number_of_shards" : "1",
       "auto_expand_replicas" : "0-1",
       "hidden": true
-    }
-    ${xpack.ml.index.lifecycle.settings}
+    },
+    "index.lifecycle.name": "${xpack.ml.index.lifecycle.name}",
+    "index.lifecycle.rollover_alias": "${xpack.ml.index.lifecycle.rollover_alias}"
   },
   "mappings" : ${xpack.ml.stats.mappings},
   "aliases" : {}

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ilm/IndexLifecycleFeatureSetUsageTests.java

@@ -28,22 +28,18 @@ protected IndexLifecycleFeatureSetUsage createTestInstance() {
                 policyStats.add(PolicyStatsTests.createRandomInstance());
             }
         }
-        return new IndexLifecycleFeatureSetUsage(available, enabled, policyStats);
+        return new IndexLifecycleFeatureSetUsage(available, policyStats);
     }
 
     @Override
     protected IndexLifecycleFeatureSetUsage mutateInstance(IndexLifecycleFeatureSetUsage instance) throws IOException {
         boolean available = instance.available();
-        boolean enabled = instance.enabled();
         List<PolicyStats> policyStats = instance.getPolicyStats();
-        switch (between(0, 2)) {
+        switch (between(0, 1)) {
         case 0:
             available = available == false;
             break;
         case 1:
-            enabled = enabled == false;
-            break;
-        case 2:
             if (policyStats == null) {
                 policyStats = new ArrayList<>();
                 policyStats.add(PolicyStatsTests.createRandomInstance());
@@ -57,7 +53,7 @@ protected IndexLifecycleFeatureSetUsage mutateInstance(IndexLifecycleFeatureSetU
         default:
             throw new AssertionError("Illegal randomisation branch");
         }
-        return new IndexLifecycleFeatureSetUsage(available, enabled, policyStats);
+        return new IndexLifecycleFeatureSetUsage(available, policyStats);
     }
 
     @Override

x-pack/plugin/ilm/src/main/java/org/elasticsearch/xpack/ilm/IndexLifecycle.java

@@ -141,13 +141,11 @@ public class IndexLifecycle extends Plugin implements ActionPlugin {
     private final SetOnce<SnapshotRetentionService> snapshotRetentionService = new SetOnce<>();
     private final SetOnce<SnapshotHistoryStore> snapshotHistoryStore = new SetOnce<>();
     private Settings settings;
-    private boolean ilmEnabled;
     private boolean slmEnabled;
     private boolean transportClientMode;
 
     public IndexLifecycle(Settings settings) {
         this.settings = settings;
-        this.ilmEnabled = XPackSettings.INDEX_LIFECYCLE_ENABLED.get(settings);
         this.slmEnabled = XPackSettings.SNAPSHOT_LIFECYCLE_ENABLED.get(settings);
         this.transportClientMode = XPackPlugin.transportClientMode(settings);
     }
@@ -197,17 +195,15 @@ public Collection<Object> createComponents(Client client, ClusterService cluster
             return Collections.emptyList();
         }
         final List<Object> components = new ArrayList<>();
-        if (ilmEnabled) {
-            // This registers a cluster state listener, so appears unused but is not.
-            @SuppressWarnings("unused")
-            ILMHistoryTemplateRegistry ilmTemplateRegistry =
-                new ILMHistoryTemplateRegistry(settings, clusterService, threadPool, client, xContentRegistry);
-            ilmHistoryStore.set(new ILMHistoryStore(settings, new OriginSettingClient(client, INDEX_LIFECYCLE_ORIGIN),
-                clusterService, threadPool));
-            indexLifecycleInitialisationService.set(new IndexLifecycleService(settings, client, clusterService, threadPool,
-                getClock(), System::currentTimeMillis, xContentRegistry, ilmHistoryStore.get()));
-            components.add(indexLifecycleInitialisationService.get());
-        }
+        // This registers a cluster state listener, so appears unused but is not.
+        @SuppressWarnings("unused")
+        ILMHistoryTemplateRegistry ilmTemplateRegistry =
+            new ILMHistoryTemplateRegistry(settings, clusterService, threadPool, client, xContentRegistry);
+        ilmHistoryStore.set(new ILMHistoryStore(settings, new OriginSettingClient(client, INDEX_LIFECYCLE_ORIGIN),
+            clusterService, threadPool));
+        indexLifecycleInitialisationService.set(new IndexLifecycleService(settings, client, clusterService, threadPool,
+            getClock(), System::currentTimeMillis, xContentRegistry, ilmHistoryStore.get()));
+        components.add(indexLifecycleInitialisationService.get());
         if (slmEnabled) {
             // the template registry is a cluster state listener
             @SuppressWarnings("unused")
@@ -263,20 +259,19 @@ public List<RestHandler> getRestHandlers(Settings settings, RestController restC
             IndexScopedSettings indexScopedSettings, SettingsFilter settingsFilter, IndexNameExpressionResolver indexNameExpressionResolver,
             Supplier<DiscoveryNodes> nodesInCluster) {
         List<RestHandler> handlers = new ArrayList<>();
-        if (ilmEnabled) {
-            handlers.addAll(Arrays.asList(
-                new RestPutLifecycleAction(),
-                new RestGetLifecycleAction(),
-                new RestDeleteLifecycleAction(),
-                new RestExplainLifecycleAction(),
-                new RestRemoveIndexLifecyclePolicyAction(),
-                new RestMoveToStepAction(),
-                new RestRetryAction(),
-                new RestStopAction(),
-                new RestStartILMAction(),
-                new RestGetStatusAction()
-            ));
-        }
+        // add ILM rest handlers
+        handlers.addAll(Arrays.asList(
+            new RestPutLifecycleAction(),
+            new RestGetLifecycleAction(),
+            new RestDeleteLifecycleAction(),
+            new RestExplainLifecycleAction(),
+            new RestRemoveIndexLifecyclePolicyAction(),
+            new RestMoveToStepAction(),
+            new RestRetryAction(),
+            new RestStopAction(),
+            new RestStartILMAction(),
+            new RestGetStatusAction()
+        ));
         if (slmEnabled) {
             handlers.addAll(Arrays.asList(
                 new RestPutSnapshotLifecycleAction(),
@@ -296,20 +291,19 @@ public List<RestHandler> getRestHandlers(Settings settings, RestController restC
     @Override
     public List<ActionHandler<? extends ActionRequest, ? extends ActionResponse>> getActions() {
         List<ActionHandler<? extends ActionRequest, ? extends ActionResponse>> actions = new ArrayList<>();
-        if (ilmEnabled) {
-            actions.addAll(Arrays.asList(
-                new ActionHandler<>(PutLifecycleAction.INSTANCE, TransportPutLifecycleAction.class),
-                new ActionHandler<>(GetLifecycleAction.INSTANCE, TransportGetLifecycleAction.class),
-                new ActionHandler<>(DeleteLifecycleAction.INSTANCE, TransportDeleteLifecycleAction.class),
-                new ActionHandler<>(ExplainLifecycleAction.INSTANCE, TransportExplainLifecycleAction.class),
-                new ActionHandler<>(RemoveIndexLifecyclePolicyAction.INSTANCE, TransportRemoveIndexLifecyclePolicyAction.class),
-                new ActionHandler<>(MoveToStepAction.INSTANCE, TransportMoveToStepAction.class),
-                new ActionHandler<>(RetryAction.INSTANCE, TransportRetryAction.class),
-                new ActionHandler<>(StartILMAction.INSTANCE, TransportStartILMAction.class),
-                new ActionHandler<>(StopILMAction.INSTANCE, TransportStopILMAction.class),
-                new ActionHandler<>(GetStatusAction.INSTANCE, TransportGetStatusAction.class)
-            ));
-        }
+        // add ILM actions
+        actions.addAll(Arrays.asList(
+            new ActionHandler<>(PutLifecycleAction.INSTANCE, TransportPutLifecycleAction.class),
+            new ActionHandler<>(GetLifecycleAction.INSTANCE, TransportGetLifecycleAction.class),
+            new ActionHandler<>(DeleteLifecycleAction.INSTANCE, TransportDeleteLifecycleAction.class),
+            new ActionHandler<>(ExplainLifecycleAction.INSTANCE, TransportExplainLifecycleAction.class),
+            new ActionHandler<>(RemoveIndexLifecyclePolicyAction.INSTANCE, TransportRemoveIndexLifecyclePolicyAction.class),
+            new ActionHandler<>(MoveToStepAction.INSTANCE, TransportMoveToStepAction.class),
+            new ActionHandler<>(RetryAction.INSTANCE, TransportRetryAction.class),
+            new ActionHandler<>(StartILMAction.INSTANCE, TransportStartILMAction.class),
+            new ActionHandler<>(StopILMAction.INSTANCE, TransportStopILMAction.class),
+            new ActionHandler<>(GetStatusAction.INSTANCE, TransportGetStatusAction.class)
+        ));
         if (slmEnabled) {
             actions.addAll(Arrays.asList(
                 new ActionHandler<>(PutSnapshotLifecycleAction.INSTANCE, TransportPutSnapshotLifecycleAction.class),
@@ -328,10 +322,8 @@ public List<RestHandler> getRestHandlers(Settings settings, RestController restC
 
     @Override
     public void onIndexModule(IndexModule indexModule) {
-        if (ilmEnabled) {
-            assert indexLifecycleInitialisationService.get() != null;
-            indexModule.addIndexEventListener(indexLifecycleInitialisationService.get());
-        }
+        assert indexLifecycleInitialisationService.get() != null;
+        indexModule.addIndexEventListener(indexLifecycleInitialisationService.get());
     }
 
     @Override

x-pack/plugin/ilm/src/main/java/org/elasticsearch/xpack/ilm/IndexLifecycleFeatureSet.java

@@ -11,11 +11,9 @@
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.inject.Inject;
-import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.license.XPackLicenseState;
 import org.elasticsearch.xpack.core.XPackFeatureSet;
 import org.elasticsearch.xpack.core.XPackField;
-import org.elasticsearch.xpack.core.XPackSettings;
 import org.elasticsearch.xpack.core.ilm.IndexLifecycleFeatureSetUsage;
 import org.elasticsearch.xpack.core.ilm.IndexLifecycleFeatureSetUsage.PhaseStats;
 import org.elasticsearch.xpack.core.ilm.IndexLifecycleFeatureSetUsage.PolicyStats;
@@ -29,14 +27,12 @@
 
 public class IndexLifecycleFeatureSet implements XPackFeatureSet {
 
-    private final boolean enabled;
     private final XPackLicenseState licenseState;
     private ClusterService clusterService;
 
     @Inject
-    public IndexLifecycleFeatureSet(Settings settings, @Nullable XPackLicenseState licenseState, ClusterService clusterService) {
+    public IndexLifecycleFeatureSet(@Nullable XPackLicenseState licenseState, ClusterService clusterService) {
         this.clusterService = clusterService;
-        this.enabled = XPackSettings.INDEX_LIFECYCLE_ENABLED.get(settings);
         this.licenseState = licenseState;
     }
 
@@ -52,7 +48,7 @@ public boolean available() {
 
     @Override
     public boolean enabled() {
-        return enabled;
+        return true;
     }
 
     @Override
@@ -83,9 +79,9 @@ public void usage(ActionListener<XPackFeatureSet.Usage> listener) {
                 }).collect(Collectors.toMap(Tuple::v1, Tuple::v2));
                 return new PolicyStats(phaseStats, policyUsage.getOrDefault(policy.getName(), 0));
             }).collect(Collectors.toList());
-            listener.onResponse(new IndexLifecycleFeatureSetUsage(available(), enabled(), policyStats));
+            listener.onResponse(new IndexLifecycleFeatureSetUsage(available(), policyStats));
         } else {
-            listener.onResponse(new IndexLifecycleFeatureSetUsage(available(), enabled()));
+            listener.onResponse(new IndexLifecycleFeatureSetUsage(available()));
         }
     }