IGNITE-26737 Deprecate non-colocation mode in 3.1 (#6797)

Author: rpuch

modules/core/src/main/java/org/apache/ignite/internal/lang/IgniteSystemProperties.java

@@ -44,7 +44,12 @@ public final class IgniteSystemProperties {
     public static final String IGNITE_SKIP_STORAGE_UPDATE_IN_BENCHMARK = "IGNITE_SKIP_STORAGE_UPDATE_IN_BENCHMARK";
 
     // TODO https://issues.apache.org/jira/browse/IGNITE-22522 Remove this feature flag.
-    /** Enables zone based replication (aka colocation) feature. */
+    /**
+     * Enables zone based replication (aka colocation) feature.
+     *
+     * @deprecated Non-colocation mode is planned to be removed in version 3.2.
+     */
+    @Deprecated(since = "3.1", forRemoval = true)
     public static final String COLOCATION_FEATURE_FLAG = "IGNITE_ZONE_BASED_REPLICATION";
 
     /**
@@ -60,8 +65,10 @@ private IgniteSystemProperties() {
      *
      * <p>Do not use in production code (apart from {@link NodeProperties} implementations). If a component needs colocation status,
      * it should get one from {@link NodeProperties}.
+     *
+     * @deprecated Non-colocation mode is planned to be removed in version 3.2.
      */
-    @Deprecated
+    @Deprecated(since = "3.1", forRemoval = true)
     public static boolean colocationEnabled() {
         return getBoolean(COLOCATION_FEATURE_FLAG, true);
     }

modules/runner/src/main/java/org/apache/ignite/internal/app/NodePropertiesImpl.java

@@ -89,6 +89,10 @@ private void detectAndSaveColocationStatusIfNeeded() {
                     IgniteSystemProperties.colocationEnabled()
             );
         }
+        if (!colocationEnabled) {
+            LOG.warn("Zone based replication is disabled, this mode is deprecated and will be removed in version 3.2. "
+                    + "Consider migrating to zone based replication (which is default now).");
+        }
     }
 
     private void saveToVault(boolean enablementStatus) {