Hi. We have SolrCloud enabled on production environment (2 Solr [16 GB RAM each] nodes and 3 Zookeeper nodes, each hosted on separate server)
Quite seldom Solr loose connection to zookeeper search stop working. After we restarting all zookeeper nodes at a time - it starts working again I Solr logs I can find next errors: 1/21/2020, 7:48:01 PM ERROR true OverseerTaskProcessor org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /overseer_elect/leader at org.apache.zookeeper.KeeperException.create(KeeperException.java:99) at org.apache.zookeeper.KeeperException.create(KeeperException.java:51) at org.apache.zookeeper.ZooKeeper.getData(ZooKeeper.java:1212) at org.apache.solr.common.cloud.SolrZkClient.lambda$getData$5(SolrZkClient.java:339) at org.apache.solr.common.cloud.ZkCmdExecutor.retryOperation(ZkCmdExecutor.java:60) at org.apache.solr.common.cloud.SolrZkClient.getData(SolrZkClient.java:339) at org.apache.solr.cloud.OverseerTaskProcessor.amILeader(OverseerTaskProcessor.java:387) at org.apache.solr.cloud.OverseerTaskProcessor.run(OverseerTaskProcessor.java:193) at java.lang.Thread.run(Unknown Source) 1/21/2020, 7:52:38 PM ERROR true HttpSolrCall null:org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /roles.json null:org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /roles.json at org.apache.zookeeper.KeeperException.create(KeeperException.java:99) at org.apache.zookeeper.KeeperException.create(KeeperException.java:51) at org.apache.zookeeper.ZooKeeper.exists(ZooKeeper.java:1102) at org.apache.solr.common.cloud.SolrZkClient.lambda$exists$3(SolrZkClient.java:315) at org.apache.solr.common.cloud.ZkCmdExecutor.retryOperation(ZkCmdExecutor.java:60) at org.apache.solr.common.cloud.SolrZkClient.exists(SolrZkClient.java:315) at org.apache.solr.handler.admin.ClusterStatus.getClusterStatus(ClusterStatus.java:74) at org.apache.solr.handler.admin.CollectionsHandler$CollectionOperation.lambda$static$20(CollectionsHandler.java:682) at org.apache.solr.handler.admin.CollectionsHandler$CollectionOperation.execute(CollectionsHandler.java:957) at org.apache.solr.handler.admin.CollectionsHandler.invokeAction(CollectionsHandler.java:237) at org.apache.solr.handler.admin.CollectionsHandler.handleRequestBody(CollectionsHandler.java:224) at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:177) at org.apache.solr.servlet.HttpSolrCall.handleAdmin(HttpSolrCall.java:735) at org.apache.solr.servlet.HttpSolrCall.handleAdminRequest(HttpSolrCall.java:716) at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:497) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:382) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:326) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1751) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:582) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:226) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1180) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:512) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1112) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:213) at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:119) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134) at org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:335) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134) at org.eclipse.jetty.server.Server.handle(Server.java:534) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:320) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:283) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:108) at org.eclipse.jetty.io.SelectChannelEndPoint$2.run(SelectChannelEndPoint.java:93) at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.executeProduceConsume(ExecuteProduceConsume.java:303) at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.produceConsume(ExecuteProduceConsume.java:148) at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.run(ExecuteProduceConsume.java:136) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:671) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:589) at java.lang.Thread.run(Unknown Source) Can you advise please how can we fix this and what is causing this exception?
