Adding node deprecation info API check for frozen cache setting (#77085)

In 8.0 the ability to have a positive "xpack.searchable.snapshot.shared_cache.size" on a non-frozen node
has been removed. This commit adds a deprecation info API check if a non-frozen node has a positive
 "xpack.searchable.snapshot.shared_cache.size".
Relates #42404 #71013

Author: masseyke

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

@@ -98,6 +98,7 @@ private DeprecationChecks() {
                     NodeDeprecationChecks::checkImplicitlyDisabledSecurityOnBasicAndTrial,
                     NodeDeprecationChecks::checkSearchRemoteSettings,
                     NodeDeprecationChecks::checkMonitoringExporterPassword,
+                    NodeDeprecationChecks::checkFrozenCacheLeniency,
                     NodeDeprecationChecks::checkSslServerEnabled,
                     NodeDeprecationChecks::checkSslCertConfiguration,
                     NodeDeprecationChecks::checkClusterRoutingAllocationIncludeRelocationsSetting,

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

@@ -20,6 +20,7 @@
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Setting.Property;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.ssl.SslConfigurationKeys;
 import org.elasticsearch.common.util.concurrent.EsExecutors;
 import org.elasticsearch.common.util.set.Sets;
@@ -35,6 +36,7 @@
 import org.elasticsearch.script.ScriptService;
 import org.elasticsearch.threadpool.FixedExecutorBuilder;
 import org.elasticsearch.transport.RemoteClusterService;
+import org.elasticsearch.xpack.core.DataTier;
 import org.elasticsearch.transport.SniffConnectionStrategy;
 import org.elasticsearch.transport.TransportService;
 import org.elasticsearch.xpack.core.XPackSettings;
@@ -669,6 +671,30 @@ static DeprecationIssue checkClusterRoutingAllocationIncludeRelocationsSetting(f
         );
     }
 
+    static DeprecationIssue checkFrozenCacheLeniency(final Settings settings,
+                                                     final PluginsAndModules pluginsAndModules,
+                                                     final ClusterState clusterState,
+                                                     final XPackLicenseState licenseState) {
+        final String cacheSizeSettingKey = "xpack.searchable.snapshot.shared_cache.size";
+        Setting<ByteSizeValue> cacheSizeSetting =  Setting.byteSizeSetting(cacheSizeSettingKey,  ByteSizeValue.ZERO);
+        if (cacheSizeSetting.exists(settings)) {
+            ByteSizeValue cacheSize = cacheSizeSetting.get(settings);
+            if (cacheSize.getBytes() > 0) {
+                final List<DiscoveryNodeRole> roles = NodeRoleSettings.NODE_ROLES_SETTING.get(settings);
+                if (DataTier.isFrozenNode(new HashSet<>(roles)) == false) {
+                    String message = String.format(Locale.ROOT, "setting [%s] cannot be greater than zero on non-frozen nodes",
+                        cacheSizeSettingKey);
+                    String url =
+                        "https://www.elastic.co/guide/en/elasticsearch/reference/master/migrating-8.0.html#breaking_80_settings_changes";
+                    String details = String.format(Locale.ROOT, "setting [%s] cannot be greater than zero on non-frozen nodes, and is " +
+                        "currently set to [%s]", cacheSizeSettingKey, settings.get(cacheSizeSettingKey));
+                    return new DeprecationIssue(DeprecationIssue.Level.CRITICAL, message, url, details, false, null);
+                }
+            }
+        }
+        return null;
+    }
+
     static DeprecationIssue checkSslServerEnabled(final Settings settings,
                                                    final PluginsAndModules pluginsAndModules,
                                                    final ClusterState clusterState,

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

@@ -963,6 +963,70 @@ public void testImplicitlyConfiguredSecurityOnGoldPlus() {
         assertThat(issues, empty());
     }
 
+    public void testCheckFrozenCacheLeniency() {
+        String cacheSizeSettingValue = "10gb";
+        String cacheSizeSettingKey = "xpack.searchable.snapshot.shared_cache.size";
+        Settings nodeSettings = Settings.builder()
+            .put(cacheSizeSettingKey, cacheSizeSettingValue)
+            .put("node.roles", "data_warm")
+            .build();
+        final XPackLicenseState licenseState = new XPackLicenseState(Settings.EMPTY, () -> 0);
+        final ClusterState clusterState = ClusterState.EMPTY_STATE;
+        DeprecationIssue expectedIssue = new DeprecationIssue(DeprecationIssue.Level.CRITICAL,
+            String.format(Locale.ROOT,
+                "setting [%s] cannot be greater than zero on non-frozen nodes",
+                cacheSizeSettingKey),
+            "https://www.elastic.co/guide/en/elasticsearch/reference/master/migrating-8.0.html#breaking_80_settings_changes",
+            String.format(Locale.ROOT,
+                "setting [%s] cannot be greater than zero on non-frozen nodes, and is currently set to [%s]",
+                cacheSizeSettingKey,
+                cacheSizeSettingValue),
+            false,null
+        );
+        assertThat(
+            NodeDeprecationChecks.checkFrozenCacheLeniency(nodeSettings, null, clusterState, licenseState),
+            equalTo(expectedIssue)
+        );
+
+        // If no 'node.roles' is specified, a node gets all roles:
+        nodeSettings = Settings.builder()
+            .put(cacheSizeSettingKey, cacheSizeSettingValue)
+            .build();
+        assertThat(
+            NodeDeprecationChecks.checkFrozenCacheLeniency(nodeSettings, null, clusterState, licenseState),
+            equalTo(null)
+        );
+
+        // No deprecation warning on a frozen node:
+        nodeSettings = Settings.builder()
+            .put(cacheSizeSettingKey, cacheSizeSettingValue)
+            .put("node.roles", "data_frozen")
+            .build();
+        assertThat(
+            NodeDeprecationChecks.checkFrozenCacheLeniency(nodeSettings, null, clusterState, licenseState),
+            equalTo(null)
+        );
+
+        // No cache size specified, so no deprecation warning:
+        nodeSettings = Settings.builder()
+            .put("node.roles", "data_warm")
+            .build();
+        assertThat(
+            NodeDeprecationChecks.checkFrozenCacheLeniency(nodeSettings, null, clusterState, licenseState),
+            equalTo(null)
+        );
+
+        // Cache size is not positive, so no deprecation wawrning:
+        nodeSettings = Settings.builder()
+            .put(cacheSizeSettingKey, "0b")
+            .put("node.roles", "data_warm")
+            .build();
+        assertThat(
+            NodeDeprecationChecks.checkFrozenCacheLeniency(nodeSettings, null, clusterState, licenseState),
+            equalTo(null)
+        );
+    }
+
     public void testCheckSslServerEnabled() {
         String httpSslEnabledKey = "xpack.security.http.ssl.enabled";
         String transportSslEnabledKey = "xpack.security.transport.ssl.enabled";