Thank you for the reply. Sorry I did not include more information in the first post.
So maybe there's some confusion here from my end. So both the target and source clusters are running in cloud mode. So I think you're correct that it is a different issue. So it looks like the source leader to target leader is successful but the target leader is then unsuccessful in replicating to its followers. The "unable to locate core" message is originally coming from the target cluster. Here are the logs being generated from the source for reference: 2019-02-02 20:10:19.551 INFO (cdcr-bootstrap-status-81-thread-1-processing-n:sourcehost001.com:30100_solr x:testcollection_shard3_replica_n10 c:testcollection s:shard3 r:core_node12) [c:testcollection s:shard3 r:core_node12 x:testcollection_shard3_replica_n10] o.a.s.h.CdcrReplicatorManager CDCR bootstrap successful in 3 seconds 2019-02-02 20:10:19.564 INFO (cdcr-bootstrap-status-81-thread-1-processing-n:sourcehost001.com:30100_solr x:testcollection_shard3_replica_n10 c:testcollection s:shard3 r:core_node12) [c:testcollection s:shard3 r:core_node12 x:testcollection_shard3_replica_n10] o.a.s.h.CdcrReplicatorManager Create new update log reader for target testcollection with checkpoint 1624389130873995265 @ testcollection:shard3 2019-02-02 20:10:19.568 ERROR (cdcr-bootstrap-status-81-thread-1-processing-n:sourcehost001.com:30100_solr x:testcollection_shard3_replica_n10 c:testcollection s:shard3 r:core_node12) [c:testcollection s:shard3 r:core_node12 x:testcollection_shard3_replica_n10] o.a.s.h.CdcrReplicatorManager Unable to bootstrap the target collection testcollection shard: shard3 org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException: Error from server at http://targethost001.com:30100/solr: Unable to locate core testcollection_shard2_replica_n4 at org.apache.solr.client.solrj.impl.HttpSolrClient.executeMethod(HttpSolrClient.java:643) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.HttpSolrClient.request(HttpSolrClient.java:255) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.HttpSolrClient.request(HttpSolrClient.java:244) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.LBHttpSolrClient.doRequest(LBHttpSolrClient.java:483) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.LBHttpSolrClient.request(LBHttpSolrClient.java:413) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.CloudSolrClient.sendRequest(CloudSolrClient.java:1107) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.CloudSolrClient.requestWithRetryOnStaleState(CloudSolrClient.java:884) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.CloudSolrClient.request(CloudSolrClient.java:817) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.SolrClient.request(SolrClient.java:1219) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.handler.CdcrReplicatorManager.sendRequestRecoveryToFollower(CdcrReplicatorManager.java:439) ~[solr-core-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:55] at org.apache.solr.handler.CdcrReplicatorManager.sendRequestRecoveryToFollowers(CdcrReplicatorManager.java:428) ~[solr-core-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:55] at org.apache.solr.handler.CdcrReplicatorManager.access$300(CdcrReplicatorManager.java:63) ~[solr-core-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:55] at org.apache.solr.handler.CdcrReplicatorManager$BootstrapStatusRunnable.run(CdcrReplicatorManager.java:306) ~[solr-core-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:55] at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_192] at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_192] at org.apache.solr.common.util.ExecutorUtil$MDCAwareThreadPoolExecutor.lambda$execute$0(ExecutorUtil.java:209) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_192] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_192] at java.lang.Thread.run(Thread.java:748) [?:1.8.0_192] 2019-02-02 20:10:19.602 INFO (cdcr-bootstrap-status-86-thread-1) [ ] o.a.s.h.CdcrReplicatorManager CDCR bootstrap successful in 3 seconds 2019-02-02 20:10:19.608 INFO (cdcr-bootstrap-status-86-thread-1) [ ] o.a.s.h.CdcrReplicatorManager Create new update log reader for target testcollection with checkpoint 1624389130873995265 @ testcollection:shard2 2019-02-02 20:10:19.610 ERROR (cdcr-bootstrap-status-86-thread-1) [ ] o.a.s.h.CdcrReplicatorManager Unable to bootstrap the target collection testcollection shard: shard2 org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException: Error from server at http://targethost001.com:30100/solr: Unable to locate core testcollection_shard2_replica_n4 at org.apache.solr.client.solrj.impl.HttpSolrClient.executeMethod(HttpSolrClient.java:643) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.HttpSolrClient.request(HttpSolrClient.java:255) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.HttpSolrClient.request(HttpSolrClient.java:244) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.LBHttpSolrClient.doRequest(LBHttpSolrClient.java:483) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.LBHttpSolrClient.request(LBHttpSolrClient.java:413) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.CloudSolrClient.sendRequest(CloudSolrClient.java:1107) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.CloudSolrClient.requestWithRetryOnStaleState(CloudSolrClient.java:884) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.impl.CloudSolrClient.request(CloudSolrClient.java:817) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.client.solrj.SolrClient.request(SolrClient.java:1219) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at org.apache.solr.handler.CdcrReplicatorManager.sendRequestRecoveryToFollower(CdcrReplicatorManager.java:439) ~[solr-core-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:55] at org.apache.solr.handler.CdcrReplicatorManager.sendRequestRecoveryToFollowers(CdcrReplicatorManager.java:428) ~[solr-core-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:55] at org.apache.solr.handler.CdcrReplicatorManager.access$300(CdcrReplicatorManager.java:63) ~[solr-core-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:55] at org.apache.solr.handler.CdcrReplicatorManager$BootstrapStatusRunnable.run(CdcrReplicatorManager.java:306) ~[solr-core-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:55] at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_192] at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_192] at org.apache.solr.common.util.ExecutorUtil$MDCAwareThreadPoolExecutor.lambda$execute$0(ExecutorUtil.java:209) ~[solr-solrj-7.5.0.jar:7.5.0 b5bf70b7e32d7ddd9742cc821d471c5fabd4e3df - jimczi - 2018-09-18 13:07:58] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_192] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_192] at java.lang.Thread.run(Thread.java:748) [?:1.8.0_192] Here are the logs from the target: 2019-02-02 20:10:19.566 INFO (qtp1571967156-14) [ x:testcollection_shard2_replica_n4] o.a.s.h.a.CoreAdminOperation It has been requested that we recover: core=testcollection_shard2_replica_n4 2019-02-02 20:10:19.567 ERROR (qtp1571967156-14) [ x:testcollection_shard2_replica_n4] o.a.s.h.RequestHandlerBase org.apache.solr.common.SolrException: Unable to locate core testcollection_shard2_replica_n4 at org.apache.solr.handler.admin.CoreAdminOperation.lambda$static$5(CoreAdminOperation.java:167) at org.apache.solr.handler.admin.CoreAdminOperation.execute(CoreAdminOperation.java:360) at org.apache.solr.handler.admin.CoreAdminHandler$CallInfo.call(CoreAdminHandler.java:395) at org.apache.solr.handler.admin.CoreAdminHandler.handleRequestBody(CoreAdminHandler.java:180) at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:199) at org.apache.solr.servlet.HttpSolrCall.handleAdmin(HttpSolrCall.java:734) at org.apache.solr.servlet.HttpSolrCall.handleAdminRequest(HttpSolrCall.java:715) at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:496) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:377) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:323) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1634) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:219) at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:335) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.Server.handle(Server.java:531) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102) at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126) at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680) at java.lang.Thread.run(Thread.java:748) 2019-02-02 20:10:19.567 INFO (qtp1571967156-14) [ x:testcollection_shard2_replica_n4] o.a.s.s.HttpSolrCall [admin] webapp=null path=/admin/cores params={core=testcollection_shard2_replica_n4&action=REQUESTRECOVERY&wt=javabin&version=2} status=400 QTime=0 2019-02-02 20:10:19.607 INFO (qtp1571967156-133) [c:testcollection s:shard1 r:core_node5 x:testcollection_shard1_replica_n2] o.a.s.c.S.Request [testcollection_shard1_replica_n2] webapp=/solr path=/cdcr params={_stateVer_=testcollection:6&action=COLLECTIONCHECKPOINT&wt=javabin&version=2} status=0 QTime=4 2019-02-02 20:10:19.609 INFO (qtp1571967156-14) [ x:testcollection_shard2_replica_n4] o.a.s.h.a.CoreAdminOperation It has been requested that we recover: core=testcollection_shard2_replica_n4 2019-02-02 20:10:19.609 ERROR (qtp1571967156-14) [ x:testcollection_shard2_replica_n4] o.a.s.h.RequestHandlerBase org.apache.solr.common.SolrException: Unable to locate core testcollection_shard2_replica_n4 at org.apache.solr.handler.admin.CoreAdminOperation.lambda$static$5(CoreAdminOperation.java:167) at org.apache.solr.handler.admin.CoreAdminOperation.execute(CoreAdminOperation.java:360) at org.apache.solr.handler.admin.CoreAdminHandler$CallInfo.call(CoreAdminHandler.java:395) at org.apache.solr.handler.admin.CoreAdminHandler.handleRequestBody(CoreAdminHandler.java:180) at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:199) at org.apache.solr.servlet.HttpSolrCall.handleAdmin(HttpSolrCall.java:734) at org.apache.solr.servlet.HttpSolrCall.handleAdminRequest(HttpSolrCall.java:715) at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:496) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:377) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:323) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1634) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:219) at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:335) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.Server.handle(Server.java:531) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102) at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126) at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680) at java.lang.Thread.run(Thread.java:748) 2019-02-02 20:10:19.609 INFO (qtp1571967156-14) [ x:testcollection_shard2_replica_n4] o.a.s.s.HttpSolrCall [admin] webapp=null path=/admin/cores params={core=testcollection_shard2_replica_n4&action=REQUESTRECOVERY&wt=javabin&version=2} status=400 QTime=0 2019-02-02 20:10:19.701 INFO (qtp1571967156-135) [ x:testcollection_shard2_replica_n4] o.a.s.h.a.CoreAdminOperation It has been requested that we recover: core=testcollection_shard2_replica_n4 2019-02-02 20:10:19.702 ERROR (qtp1571967156-135) [ x:testcollection_shard2_replica_n4] o.a.s.h.RequestHandlerBase org.apache.solr.common.SolrException: Unable to locate core testcollection_shard2_replica_n4 at org.apache.solr.handler.admin.CoreAdminOperation.lambda$static$5(CoreAdminOperation.java:167) at org.apache.solr.handler.admin.CoreAdminOperation.execute(CoreAdminOperation.java:360) at org.apache.solr.handler.admin.CoreAdminHandler$CallInfo.call(CoreAdminHandler.java:395) at org.apache.solr.handler.admin.CoreAdminHandler.handleRequestBody(CoreAdminHandler.java:180) at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:199) at org.apache.solr.servlet.HttpSolrCall.handleAdmin(HttpSolrCall.java:734) at org.apache.solr.servlet.HttpSolrCall.handleAdminRequest(HttpSolrCall.java:715) at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:496) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:377) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:323) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1634) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:219) at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:335) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.Server.handle(Server.java:531) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102) at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126) at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680) at java.lang.Thread.run(Thread.java:748) 2019-02-02 20:10:19.702 INFO (qtp1571967156-135) [ x:testcollection_shard2_replica_n4] o.a.s.s.HttpSolrCall [admin] webapp=null path=/admin/cores params={core=testcollection_shard2_replica_n4&action=REQUESTRECOVERY&wt=javabin&version=2} status=400 QTime=0 So the leader to leader replication is successful but the target leader is not able to replicate to the follower. So after some more investigation I found it's the call to recover the core that is having issues. When it makes the call to /solr/admin/cores?core=testcollection_shard2_replica_n4&action=REQUESTRECOVERY that is when it is unable to locate core. It's actually sending the call to the wrong host. So our setup is like the following: numShards: 3, replicationFact: 2, maxShards: 2. I wanted to retest it so I deleted and recreated the collection and the aftermath looked like the following: targetServer1s: s2r4 (shard 3, replica8), s3r10 targetServer2: s1,r1, s3r8, targetServer3: s2r6, s3r10 sourceServer1: s2r4, s3r10 sourceServer2: s1r2, s3r8 sourceServer3: s1r1, s2r6 When running CDCR once again the replication to the leaders was successful. The leaders for both were: s2r4, s3r10, s1r1. After CDCR, the source cluster made a call to recover s2r6. The source sent this call to targetServer1 which contained s2r4, and s3r10. As s2r6 is on targetServer3, the call was unsuccessful as it was not able to locate s2r6 on targetServer1. Unsure of a fix at this time. -----Original Message----- From: Erick Erickson [mailto:erickerick...@gmail.com] Sent: Saturday, February 2, 2019 9:56 AM To: solr-user <solr-user@lucene.apache.org> Subject: [EXTERNAL] Re: [CDCR]Unable to locate core CDCR does _not_ replicate to followers, it is a leader<->leader replication of the raw document. Once the document has been forwarded to the target's leader, then the leader on the target system should forward it to followers on that system just like any other update. The Solr JIRA is unlikely the problem from what you describe. 1> are you sure you are _committing_ on the target system? 2> "unable to locate core" comes from where? The source? Target? CDCR? 3> is your target collection properly set up? Because it sounds a bit like your target cluster isn't running in SolrCloud mode. Best, Erick On Fri, Feb 1, 2019 at 12:48 PM Tim <timothy.springst...@gm.com> wrote: > > After some more investigation it seems that we're running into the > same bug found here <https://issues.apache.org/jira/browse/SOLR-11724> . > > However if my understanding is correct that bug in 7.3 was patched out. > Unfortunately we're running into the same behavior in 7.5 > > CDCR is replicating successfully to the leader node but is not > replicating to the followers. > > > > -- > Sent from: http://lucene.472066.n3.nabble.com/Solr-User-f472068.html Nothing in this message is intended to constitute an electronic signature unless a specific statement to the contrary is included in this message. Confidentiality Note: This message is intended only for the person or entity to which it is addressed. It may contain confidential and/or privileged material. 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