{"record":{"id":"23d397e827bc4638","repo":"apache/hadoop","slug":"remote-namenodes-not-correctly-configured","errorCode":null,"errorMessage":"Remote NameNodes not correctly configured!","messagePattern":"Remote NameNodes not correctly configured!","errorType":"exception","errorClass":"IllegalArgumentException","httpStatus":null,"severity":"critical","filePath":"hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/EditLogTailer.java","lineNumber":206,"sourceCode":" public EditLogTailer(FSNamesystem namesystem, Configuration conf) {\n this.tailerThread = new EditLogTailerThread();\n this.conf = conf;\n this.namesystem = namesystem;\n this.timer = new Timer();\n this.editLog = namesystem.getEditLog();\n this.lastLoadTimeMs = timer.monotonicNow();\n this.lastRollTimeMs = timer.monotonicNow();\n\n logRollPeriodMs = conf.getTimeDuration(\n DFSConfigKeys.DFS_HA_LOGROLL_PERIOD_KEY,\n DFSConfigKeys.DFS_HA_LOGROLL_PERIOD_DEFAULT,\n TimeUnit.SECONDS, TimeUnit.MILLISECONDS);\n List nns = Collections.emptyList();\n if (logRollPeriodMs >= 0) {\n try {\n nns = RemoteNameNodeInfo.getRemoteNameNodes(conf);\n } catch (IOException e) {\n throw new IllegalArgumentException(\"Remote NameNodes not correctly configured!\", e);\n }\n\n for (RemoteNameNodeInfo info : nns) {\n // overwrite the socket address, if we need to\n InetSocketAddress ipc = NameNode.getServiceAddress(info.getConfiguration(), true);\n // sanity check the ipc address\n Preconditions.checkArgument(ipc.getPort() > 0,\n \"Active NameNode must have an IPC port configured. \" + \"Got address '%s'\", ipc);\n info.setIpcAddress(ipc);\n }\n\n LOG.info(\"Will roll logs on active node every \" +\n (logRollPeriodMs / 1000) + \" seconds.\");\n } else {\n LOG.info(\"Not going to trigger log rolls on active node because \" +\n DFSConfigKeys.DFS_HA_LOGROLL_PERIOD_KEY + \" is negative.\");\n }\n ","sourceCodeStart":188,"sourceCodeEnd":224,"githubUrl":"https://github.com/apache/hadoop/blob/2add9630210752f88ceb1bb74eb65e37bf41da8e/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/EditLogTailer.java#L188-L224","documentation":"Thrown by the standby NameNode's EditLogTailer constructor. When dfs.ha.log-roll.period >= 0 (default 120s), the tailer must find the other NameNodes in the nameservice to roll and tail their edit logs; RemoteNameNodeInfo.getRemoteNameNodes(conf) re-reads the HA topology (dfs.nameservices / dfs.internal.nameservices, dfs.ha.namenodes., dfs.namenode.rpc-address..) and throws IOException when it cannot resolve the peer NNs. The tailer wraps that IOException in IllegalArgumentException, which aborts NameNode startup or the transition to standby.","triggerScenarios":"Starting a NameNode (or transitioning it to standby) while log rolling is enabled and: (a) this NN's nameservice id has no dfs.ha.namenodes. entry, (b) an NN id listed there has no dfs.namenode.rpc-address.. so NameNode.getServiceAddress cannot build a socket address, or (c) a host in one of those addresses is unresolvable, making HAUtil.getConfForOtherNodes fail.","commonSituations":"Hand-edited hdfs-site.xml with a typo in dfs.ha.namenodes.* or a missing per-NN address suffix; cloning one node's config to another without the . suffixed keys; federation misconfiguration of dfs.internal.nameservices; DNS entries for NN hosts missing.","solutions":["Fix the HA topology in hdfs-site.xml: set dfs.ha.namenodes. to all NN ids and give every NN a dfs.namenode.rpc-address.. (and matching http address keys)","Verify the config as the NameNode resolves it: 'hdfs getconf -dfs.nameservices', 'hdfs getconf -dfs.ha.namenodes' and confirm each address resolves (host -t A )","Fix hostname/DNS or /etc/hosts for every listed NN address if resolution is the failure","Only if you deliberately want no edit-log tailing (not recommended in HA): set dfs.ha.log-roll.period to a negative value so remote-NN discovery is skipped"],"exampleFix":"\ndfs.ha.namenodes.myclusternn1,nn2\ndfs.namenode.rpc-address.mycluster.nn1nn1-host:8020\n\ndfs.ha.namenodes.myclusternn1,nn2\ndfs.namenode.rpc-address.mycluster.nn1nn1-host:8020\ndfs.namenode.rpc-address.mycluster.nn2nn2-host:8020","handlingStrategy":"validation","validationCode":"// Run before NN start / transitionToStandby on this host's effective config\nstatic void validateRemoteNameNodes(Configuration conf) throws IOException {\n String nsId = DFSUtil.getNamenodeNameServiceId(conf);\n if (nsId == null) return; // single-NN, no federation: nothing to check\n String idsKey = \"dfs.ha.namenodes.\" + nsId;\n String[] nnIds = conf.getTrimmedStrings(idsKey);\n if (nnIds == null || nnIds.length == 0)\n throw new IOException(idsKey + \" is not configured\");\n for (String nnId : nnIds) {\n String addrKey = \"dfs.namenode.rpc.address.\" + nsId + \".\" + nnId;\n String addr = conf.get(addrKey);\n if (addr == null || addr.isEmpty())\n throw new IOException(addrKey + \" is not configured\");\n InetAddress.getByName(addr.split(\":\")[0]); // fails on unresolvable host\n }\n}","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Template HA configs with the . suffixed address keys so a missing suffix cannot happen","Add a pre-deploy config lint (hdfs getconf + a key-presence check) to your provisioning pipeline","Resolve all NN hostnames on every node before starting or failing over","Keep both NNs' hdfs-site.xml byte-identical except where deployment tooling intentionally differs"],"tags":["hadoop","hdfs","high-availability","configuration","namenode","startup","edit-log"],"backgroundTag":"hadoop-ha-misconfiguration","analyzedSha":"2add9630210752f88ceb1bb74eb65e37bf41da8e","analyzedAt":"2026-08-22T19:55:07.957Z","schemaVersion":2},"datasetVersion":"2026-08-23T01:17:44.959Z"}