{"record":{"id":"5b0247a3070a56f3","repo":"firecracker-microvm/firecracker","slug":"unable-to-create-eventmanager","errorCode":null,"errorMessage":"Unable to create EventManager","messagePattern":"Unable to create EventManager","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"error","filePath":"src/firecracker/src/main.rs","lineNumber":636,"sourceCode":"    Shutdown(FcExitCode),\n    /// Failed to build MicroVM from Json: {0}\n    BuildMicroVMFromJson(BuildFromJsonError),\n    /// Missing vmm seccomp filter\n    MissingSeccompFilter,\n    /// Failed to install vmm seccomp filter: {0}\n    SeccompFilter(vmm::seccomp::InstallationError),\n}\n\nfn run_without_api(\n    seccomp_filters: &BpfThreadMap,\n    config_json: Option<String>,\n    instance_info: InstanceInfo,\n    bool_timer_enabled: bool,\n    pci_enabled: bool,\n    mmds_size_limit: usize,\n    metadata_json: Option<&str>,\n) -> Result<(), RunWithoutApiError> {\n    let mut event_manager = EventManager::new().expect(\"Unable to create EventManager\");\n\n    // Create the firecracker metrics object responsible for periodically printing metrics.\n    let firecracker_metrics = Arc::new(Mutex::new(metrics::PeriodicMetrics::new()));\n    event_manager.add_subscriber(firecracker_metrics.clone());\n\n    // Build the microVm. We can ignore VmResources since it's not used without api.\n    let vmm = build_microvm_from_json(\n        seccomp_filters,\n        &mut event_manager,\n        // Safe to unwrap since '--no-api' requires this to be set.\n        config_json.unwrap(),\n        instance_info,\n        bool_timer_enabled,\n        pci_enabled,\n        mmds_size_limit,\n        metadata_json,\n    )\n    .map_err(RunWithoutApiError::BuildMicroVMFromJson)?;","sourceCodeStart":618,"sourceCodeEnd":654,"githubUrl":"https://github.com/firecracker-microvm/firecracker/blob/0a745def42ddf4cc2a744d79a08a27ff50b5d27a/src/firecracker/src/main.rs#L618-L654","documentation":"Error \"Unable to create EventManager\" thrown in firecracker-microvm/firecracker.","triggerScenarios":"Thrown at src/firecracker/src/main.rs:636 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Check the process file-descriptor limit; EventManager creation fails when epoll/eventfd fds cannot be allocated.","Inspect the underlying OS error from EventManager::new for the precise cause."],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"0a745def42ddf4cc2a744d79a08a27ff50b5d27a","analyzedAt":"2026-08-19T05:27:02.517Z","contentChangedAt":"2026-08-19T05:27:02.517Z","schemaVersion":2},"datasetVersion":"2026-09-14T00:17:10.932Z"}