{"record":{"id":"8171629049de8302","repo":"apache/hadoop","slug":"fifo-scheduler-is-not-supported-yet","errorCode":null,"errorMessage":"Fifo Scheduler is not supported yet.","messagePattern":"Fifo Scheduler is not supported yet\\.","errorType":"exception","errorClass":"YarnException","httpStatus":null,"severity":"error","filePath":"hadoop-tools/hadoop-sls/src/main/java/org/apache/hadoop/yarn/sls/RMRunner.java","lineNumber":70,"sourceCode":"    this.queueAppNumMap = new HashMap<>();\n  }\n\n  public void startRM() throws ClassNotFoundException, YarnException {\n    Configuration rmConf = new YarnConfiguration(conf);\n    String schedulerClass = rmConf.get(YarnConfiguration.RM_SCHEDULER);\n\n    if (Class.forName(schedulerClass) == CapacityScheduler.class) {\n      rmConf.set(YarnConfiguration.RM_SCHEDULER,\n          SLSCapacityScheduler.class.getName());\n      rmConf.setBoolean(YarnConfiguration.RM_SCHEDULER_ENABLE_MONITORS, true);\n      rmConf.set(YarnConfiguration.RM_SCHEDULER_MONITOR_POLICIES,\n          ProportionalCapacityPreemptionPolicy.class.getName());\n    } else if (Class.forName(schedulerClass) == FairScheduler.class) {\n      rmConf.set(YarnConfiguration.RM_SCHEDULER,\n          SLSFairScheduler.class.getName());\n    } else if (Class.forName(schedulerClass) == FifoScheduler.class) {\n      // TODO add support for FifoScheduler\n      throw new YarnException(\"Fifo Scheduler is not supported yet.\");\n    }\n    rmConf.setClass(\n        CommonConfigurationKeysPublic.NET_TOPOLOGY_NODE_SWITCH_MAPPING_IMPL_KEY,\n        TableMapping.class, DNSToSwitchMapping.class);\n    rmConf.set(\n        CommonConfigurationKeysPublic.NET_TOPOLOGY_TABLE_MAPPING_FILE_KEY,\n        tableMapping);\n    rmConf.set(SLSConfiguration.METRICS_OUTPUT_DIR, metricsOutputDir);\n\n    rm = new ResourceManager() {\n      @Override\n      protected ApplicationMasterLauncher createAMLauncher() {\n        return new MockAMLauncher(slsRunner, this.rmContext);\n      }\n    };\n\n    // Across runs of parametrized tests, the JvmMetrics objects is retained,\n    // but is not registered correctly","sourceCodeStart":52,"sourceCodeEnd":88,"githubUrl":"https://github.com/apache/hadoop/blob/2add9630210752f88ceb1bb74eb65e37bf41da8e/hadoop-tools/hadoop-sls/src/main/java/org/apache/hadoop/yarn/sls/RMRunner.java#L52-L88","documentation":"Error \"Fifo Scheduler is not supported yet.\" thrown in apache/hadoop.","triggerScenarios":"SLS is configured to simulate the FIFO scheduler, which the simulator does not support; use Capacity or Fair scheduler.","commonSituations":"See trigger scenarios.","solutions":["Configure Capacity or Fair scheduler for the SLS run; Fifo is not implemented."],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"2add9630210752f88ceb1bb74eb65e37bf41da8e","analyzedAt":"2026-08-22T19:55:07.957Z","schemaVersion":2},"datasetVersion":"2026-08-23T01:17:44.959Z"}