[Segment Replication] Fix Flaky test SegmentReplicationRelocationIT.testPrimaryRelocation (#10701)

* Add primary mode check before assserting on primary mode.

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

* remove unnecessary shardRouting check.

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

* Add test logging.

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

* Addressing comments on PR.

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

---------

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>
(cherry picked from commit 1e9ec52)
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationRelocationIT.java

@@ -26,6 +26,7 @@
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.test.OpenSearchIntegTestCase;
+import org.opensearch.test.junit.annotations.TestLogging;
 import org.opensearch.test.transport.MockTransportService;
 import org.opensearch.transport.TransportService;
 
@@ -55,6 +56,7 @@ private void createIndex(int replicaCount) {
      * This test verifies happy path when primary shard is relocated newly added node (target) in the cluster. Before
      * relocation and after relocation documents are indexed and documents are verified
      */
+    @TestLogging(reason = "Getting trace logs from replication,shard and allocation package", value = "org.opensearch.indices.replication:TRACE, org.opensearch.index.shard:TRACE, org.opensearch.cluster.routing.allocation:TRACE")
     public void testPrimaryRelocation() throws Exception {
         final String oldPrimary = internalCluster().startNode();
         createIndex(1);

server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSourceHandler.java

@@ -12,8 +12,6 @@
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.StepListener;
 import org.opensearch.cluster.node.DiscoveryNode;
-import org.opensearch.cluster.routing.IndexShardRoutingTable;
-import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.common.logging.Loggers;
 import org.opensearch.common.util.CancellableThreads;
 import org.opensearch.common.util.concurrent.ListenableFuture;
@@ -22,7 +20,6 @@
 import org.opensearch.core.action.ActionListener;
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.index.store.StoreFileMetadata;
-import org.opensearch.indices.recovery.DelayRecoveryException;
 import org.opensearch.indices.recovery.FileChunkWriter;
 import org.opensearch.indices.recovery.MultiChunkTransfer;
 import org.opensearch.indices.replication.common.CopyState;
@@ -146,12 +143,6 @@ public synchronized void sendFiles(GetSegmentFilesRequest request, ActionListene
                 );
             };
             cancellableThreads.checkForCancel();
-            final IndexShardRoutingTable routingTable = shard.getReplicationGroup().getRoutingTable();
-            ShardRouting targetShardRouting = routingTable.getByAllocationId(request.getTargetAllocationId());
-            if (targetShardRouting == null) {
-                logger.debug("delaying replication of {} as it is not listed as assigned to target node {}", shard.shardId(), targetNode);
-                throw new DelayRecoveryException("source node does not have the shard listed in its state as allocated on the node");
-            }
 
             final StepListener<Void> sendFileStep = new StepListener<>();
             Set<String> storeFiles = new HashSet<>(Arrays.asList(shard.store().directory().listAll()));