apache/hadoop · error · YarnException

Fifo Scheduler is not supported yet.

Error message

Fifo Scheduler is not supported yet.

What it means

Error "Fifo Scheduler is not supported yet." thrown in apache/hadoop.

Source

Thrown at hadoop-tools/hadoop-sls/src/main/java/org/apache/hadoop/yarn/sls/RMRunner.java:70

    this.queueAppNumMap = new HashMap<>();
  }

  public void startRM() throws ClassNotFoundException, YarnException {
    Configuration rmConf = new YarnConfiguration(conf);
    String schedulerClass = rmConf.get(YarnConfiguration.RM_SCHEDULER);

    if (Class.forName(schedulerClass) == CapacityScheduler.class) {
      rmConf.set(YarnConfiguration.RM_SCHEDULER,
          SLSCapacityScheduler.class.getName());
      rmConf.setBoolean(YarnConfiguration.RM_SCHEDULER_ENABLE_MONITORS, true);
      rmConf.set(YarnConfiguration.RM_SCHEDULER_MONITOR_POLICIES,
          ProportionalCapacityPreemptionPolicy.class.getName());
    } else if (Class.forName(schedulerClass) == FairScheduler.class) {
      rmConf.set(YarnConfiguration.RM_SCHEDULER,
          SLSFairScheduler.class.getName());
    } else if (Class.forName(schedulerClass) == FifoScheduler.class) {
      // TODO add support for FifoScheduler
      throw new YarnException("Fifo Scheduler is not supported yet.");
    }
    rmConf.setClass(
        CommonConfigurationKeysPublic.NET_TOPOLOGY_NODE_SWITCH_MAPPING_IMPL_KEY,
        TableMapping.class, DNSToSwitchMapping.class);
    rmConf.set(
        CommonConfigurationKeysPublic.NET_TOPOLOGY_TABLE_MAPPING_FILE_KEY,
        tableMapping);
    rmConf.set(SLSConfiguration.METRICS_OUTPUT_DIR, metricsOutputDir);

    rm = new ResourceManager() {
      @Override
      protected ApplicationMasterLauncher createAMLauncher() {
        return new MockAMLauncher(slsRunner, this.rmContext);
      }
    };

    // Across runs of parametrized tests, the JvmMetrics objects is retained,
    // but is not registered correctly

View on GitHub (pinned to 2add963021)

Solutions

1. Configure Capacity or Fair scheduler for the SLS run; Fifo is not implemented.

When it happens

Trigger: SLS is configured to simulate the FIFO scheduler, which the simulator does not support; use Capacity or Fair scheduler.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/8171629049de8302. Report an issue: GitHub.