We are seeing behaviour in Region server logs where it's filled with below exception repeatedly. Frequency is 5 every second. It appeared to be fixed when Metadata cache update thread terminated as RS went offline (and came online again).
This is on CDAP 4.3.3 on HDP 2.6.4.
2019-02-01 06:13:10,114 ERROR [tms-topic-metadata-cache-refresh] zookeeper.ZooKeeperWatcher: hconnection-0x880720d-0x999b40acc6nhf94, quorum=hostname:2181, baseZNode=/hbase-secure Received unexpected KeeperException, re-throwing exception
org.apache.zookeeper.KeeperException$AuthFailedException: KeeperErrorCode = AuthFailed for /hbase-secure/meta-region-server
at org.apache.zookeeper.KeeperException.create(KeeperException.java:123)
at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
at org.apache.zookeeper.ZooKeeper.getData(ZooKeeper.java:1155)
at org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper.getData(RecoverableZooKeeper.java:354)
at org.apache.hadoop.hbase.zookeeper.ZKUtil.getData(ZKUtil.java:624)
at org.apache.hadoop.hbase.zookeeper.MetaTableLocator.getMetaRegionState(MetaTableLocator.java:491)
at org.apache.hadoop.hbase.zookeeper.MetaTableLocator.getMetaRegionLocation(MetaTableLocator.java:172)
at org.apache.hadoop.hbase.zookeeper.MetaTableLocator.blockUntilAvailable(MetaTableLocator.java:611)
at org.apache.hadoop.hbase.zookeeper.MetaTableLocator.blockUntilAvailable(MetaTableLocator.java:592)
at org.apache.hadoop.hbase.zookeeper.MetaTableLocator.blockUntilAvailable(MetaTableLocator.java:565)
at org.apache.hadoop.hbase.client.ZooKeeperRegistry.getMetaRegionLocation(ZooKeeperRegistry.java:61)
at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateMeta(ConnectionManager.java:1209)
at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegion(ConnectionManager.java:1176)
at org.apache.hadoop.hbase.client.CoprocessorHConnection.locateRegion(CoprocessorHConnection.java:41)
at org.apache.hadoop.hbase.client.RpcRetryingCallerWithReadReplicas.getRegionLocations(RpcRetryingCallerWithReadReplicas.java:340)
at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:159)
at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:61)
at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:211)
at org.apache.hadoop.hbase.client.ClientSmallReversedScanner.loadCache(ClientSmallReversedScanner.java:227)
at org.apache.hadoop.hbase.client.ClientSmallReversedScanner.next(ClientSmallReversedScanner.java:201)
at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegionInMeta(ConnectionManager.java:1275)
at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegion(ConnectionManager.java:1179)
at org.apache.hadoop.hbase.client.CoprocessorHConnection.locateRegion(CoprocessorHConnection.java:41)
at org.apache.hadoop.hbase.client.RpcRetryingCallerWithReadReplicas.getRegionLocations(RpcRetryingCallerWithReadReplicas.java:340)
at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:159)
at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:61)
at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:211)
at org.apache.hadoop.hbase.client.ClientScanner.call(ClientScanner.java:327)
at org.apache.hadoop.hbase.client.ClientScanner.nextScanner(ClientScanner.java:302)
at org.apache.hadoop.hbase.client.ClientScanner.initializeScannerInConstruction(ClientScanner.java:167)
at org.apache.hadoop.hbase.client.ClientScanner.<init>(ClientScanner.java:162)
at org.apache.hadoop.hbase.client.HTable.getScanner(HTable.java:799)
at org.apache.hadoop.hbase.client.HTableWrapper.getScanner(HTableWrapper.java:215)
at co.cask.cdap.messaging.TopicMetadataCache.updateCache(TopicMetadataCache.java:141)
at co.cask.cdap.messaging.TopicMetadataCache$2.run(TopicMetadataCache.java:183)