apache/hadoop · error · ConnectException

No namenode available to invoke {} {} in {} from {}

Error message

No namenode available to invoke {} {} in {} from {}

What it means

Error "No namenode available to invoke {} {} in {} from {}" thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterRpcClient.java:616

    for (Entry<FederationNamenodeContext, IOException> entry :
        ioes.entrySet()) {
      FederationNamenodeContext namenode = entry.getKey();
      String nnKey = namenode.getNamenodeKey();
      String addr = namenode.getRpcAddress();
      IOException ioe = entry.getValue();
      if (ioe instanceof StandbyException) {
        LOG.error("{} at {} is in Standby: {}",
            nnKey, addr, ioe.getMessage());
      } else if (isUnavailableException(ioe)) {
        exConnect++;
        LOG.error("{} at {} cannot be reached: {}",
            nnKey, addr, ioe.getMessage());
      } else {
        LOG.error("{} at {} error: \"{}\"", nnKey, addr, ioe.getMessage());
      }
    }
    if (exConnect == ioes.size()) {
      throw new ConnectException(msg);
    } else {
      throw new StandbyException(msg);
    }
  }

  /**
   * The RPC request is successfully processed by the NameNode, the NameNode status
   * in the router cache is updated according to the ExecutionStatus.
   *
   * @param method Remote method to invoke.
   * @param status Current execution status.
   * @param namenode The namenode that successfully processed this RPC request.
   * @param nsId Nameservice ID.
   * @param client Connection client.
   * @throws IOException If the state store cannot be accessed.
   */
  protected void postProcessResult(Method method, ExecutionStatus status,
      FederationNamenodeContext namenode, String nsId, ProxyAndInfo<?> client) throws IOException {

View on GitHub (pinned to 2add963021)

Solutions

1. Verify namenode registration and health for the nameservice via the Router admin CLI or /metrics.
2. Restart or repair the failing namenodes so heartbeats resume.
3. Check State Store connectivity; stale or missing membership records cause empty namenode lists.

When it happens

Trigger: No available namenode could serve the specific RPC call for the given location.

Common situations: Subcluster outage, expired namenode registrations, or router-side caching of a dead namenode list.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/797941f5fbbaaf0b. Report an issue: GitHub.