[Segment Replication] Add random replication strategy

server/src/internalClusterTest/java/org/opensearch/cluster/SimpleClusterStateIT.java

@@ -97,12 +97,17 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singletonList(PrivateCustomPlugin.class);
     }
 
+    @Override
+    protected boolean useRandomReplicationStrategy() {
+        return true;
+    }
+
     @Before
     public void indexData() throws Exception {
         index("foo", "bar", "1", XContentFactory.jsonBuilder().startObject().field("foo", "foo").endObject());
         index("fuu", "buu", "1", XContentFactory.jsonBuilder().startObject().field("fuu", "fuu").endObject());
         index("baz", "baz", "1", XContentFactory.jsonBuilder().startObject().field("baz", "baz").endObject());
-        refresh();
+        refreshAndWaitForReplication();
     }
 
     public void testRoutingTable() throws Exception {

server/src/internalClusterTest/java/org/opensearch/indices/IndicesRequestCacheIT.java

@@ -81,6 +81,11 @@ public static Collection<Object[]> parameters() {
         );
     }
 
+    @Override
+    protected boolean useRandomReplicationStrategy() {
+        return true;
+    }
+
     // One of the primary purposes of the query cache is to cache aggs results
     public void testCacheAggs() throws Exception {
         Client client = client();
@@ -180,7 +185,7 @@ public void testQueryRewrite() throws Exception {
         // Force merge the index to ensure there can be no background merges during the subsequent searches that would invalidate the cache
         ForceMergeResponse forceMergeResponse = client.admin().indices().prepareForceMerge("index").setFlush(true).get();
         OpenSearchAssertions.assertAllSuccessful(forceMergeResponse);
-        refresh();
+        refreshAndWaitForReplication();
         ensureSearchable("index");
 
         assertCacheState(client, "index", 0, 0);
@@ -250,7 +255,7 @@ public void testQueryRewriteMissingValues() throws Exception {
         // Force merge the index to ensure there can be no background merges during the subsequent searches that would invalidate the cache
         ForceMergeResponse forceMergeResponse = client.admin().indices().prepareForceMerge("index").setFlush(true).get();
         OpenSearchAssertions.assertAllSuccessful(forceMergeResponse);
-        refresh();
+        refreshAndWaitForReplication();
         ensureSearchable("index");
 
         assertCacheState(client, "index", 0, 0);
@@ -316,7 +321,7 @@ public void testQueryRewriteDates() throws Exception {
         // Force merge the index to ensure there can be no background merges during the subsequent searches that would invalidate the cache
         ForceMergeResponse forceMergeResponse = client.admin().indices().prepareForceMerge("index").setFlush(true).get();
         OpenSearchAssertions.assertAllSuccessful(forceMergeResponse);
-        refresh();
+        refreshAndWaitForReplication();
         ensureSearchable("index");
 
         assertCacheState(client, "index", 0, 0);
@@ -389,7 +394,7 @@ public void testQueryRewriteDatesWithNow() throws Exception {
             .setFlush(true)
             .get();
         OpenSearchAssertions.assertAllSuccessful(forceMergeResponse);
-        refresh();
+        refreshAndWaitForReplication();
         ensureSearchable("index-1", "index-2", "index-3");
 
         assertCacheState(client, "index-1", 0, 0);
@@ -460,7 +465,7 @@ public void testCanCache() throws Exception {
         // Force merge the index to ensure there can be no background merges during the subsequent searches that would invalidate the cache
         ForceMergeResponse forceMergeResponse = client.admin().indices().prepareForceMerge("index").setFlush(true).get();
         OpenSearchAssertions.assertAllSuccessful(forceMergeResponse);
-        refresh();
+        refreshAndWaitForReplication();
         ensureSearchable("index");
 
         assertCacheState(client, "index", 0, 0);
@@ -554,7 +559,7 @@ public void testCacheWithFilteredAlias() throws InterruptedException {
         // Force merge the index to ensure there can be no background merges during the subsequent searches that would invalidate the cache
         ForceMergeResponse forceMergeResponse = client.admin().indices().prepareForceMerge("index").setFlush(true).get();
         OpenSearchAssertions.assertAllSuccessful(forceMergeResponse);
-        refresh();
+        refreshAndWaitForReplication();
 
         indexRandomForConcurrentSearch("index");
 
@@ -661,7 +666,7 @@ public void testCacheWithInvalidation() throws Exception {
         assertCacheState(client, "index", 1, 1);
 
         // Explicit refresh would invalidate cache
-        refresh();
+        refreshAndWaitForReplication();
         // Hit same query again
         resp = client.prepareSearch("index").setRequestCache(true).setQuery(QueryBuilders.termQuery("k", "hello")).get();
         assertSearchResponse(resp);

test/framework/src/main/java/org/opensearch/test/OpenSearchIntegTestCase.java

@@ -141,6 +141,7 @@
 import org.opensearch.indices.IndicesQueryCache;
 import org.opensearch.indices.IndicesRequestCache;
 import org.opensearch.indices.IndicesService;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.indices.store.IndicesStore;
 import org.opensearch.monitor.os.OsInfo;
 import org.opensearch.node.NodeMocksPlugin;
@@ -208,6 +209,7 @@
 import static org.opensearch.index.IndexSettings.INDEX_DOC_ID_FUZZY_SET_FALSE_POSITIVE_PROBABILITY_SETTING;
 import static org.opensearch.index.IndexSettings.INDEX_SOFT_DELETES_RETENTION_LEASE_PERIOD_SETTING;
 import static org.opensearch.index.query.QueryBuilders.matchAllQuery;
+import static org.opensearch.indices.IndicesService.CLUSTER_REPLICATION_TYPE_SETTING;
 import static org.opensearch.test.XContentTestUtils.convertToMap;
 import static org.opensearch.test.XContentTestUtils.differenceBetweenMapsIgnoringArrayOrder;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
@@ -1887,9 +1889,25 @@ protected Settings nodeSettings(int nodeOrdinal) {
             builder.put(TelemetrySettings.TRACER_FEATURE_ENABLED_SETTING.getKey(), true);
             builder.put(TelemetrySettings.TRACER_ENABLED_SETTING.getKey(), true);
         }
+
+        // Randomly set a replication strategy for the node. Replication Strategy can still be manually overridden by subclass if needed.
+        if (useRandomReplicationStrategy()) {
+            ReplicationType replicationType = randomBoolean() ? ReplicationType.DOCUMENT : ReplicationType.SEGMENT;
+            logger.info("Randomly using Replication Strategy as {}.", replicationType.toString());
+            builder.put(CLUSTER_REPLICATION_TYPE_SETTING.getKey(), replicationType);
+        }
         return builder.build();
     }
 
+    /**
+     * Used for selecting random replication strategy, either DOCUMENT or SEGMENT.
+     * This method must be overridden by subclass to use random replication strategy.
+     * Should be used only on test classes where replication strategy is not critical for tests.
+     */
+    protected boolean useRandomReplicationStrategy() {
+        return false;
+    }
+
     protected Path nodeConfigPath(int nodeOrdinal) {
         return null;
     }