{"record":{"id":"f805e9a3ffb01823","repo":"hashicorp/nomad","slug":"failed-to-signal-task-s-err-v","errorCode":null,"errorMessage":"Failed to signal task: %s, err: %v","messagePattern":"Failed to signal task: (.+?), err: (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"client/allocrunner/alloc_runner.go","lineNumber":1493,"sourceCode":"// taskName is empty, then it is sent to all tasks.\nfunc (ar *allocRunner) Signal(taskName, signal string) error {\n\tevent := structs.NewTaskEvent(structs.TaskSignaling).SetSignalText(signal)\n\n\tif taskName != \"\" {\n\t\ttr, ok := ar.tasks[taskName]\n\t\tif !ok {\n\t\t\treturn fmt.Errorf(\"Task not found\")\n\t\t}\n\n\t\treturn tr.Signal(event, signal)\n\t}\n\n\tvar err *multierror.Error\n\n\tfor tn, tr := range ar.tasks {\n\t\trerr := tr.Signal(event.Copy(), signal)\n\t\tif rerr != nil {\n\t\t\terr = multierror.Append(err, fmt.Errorf(\"Failed to signal task: %s, err: %v\", tn, rerr))\n\t\t}\n\t}\n\n\treturn err.ErrorOrNil()\n}\n\n// Reconnect logs a reconnect event for each task in the allocation and syncs the current alloc state with the server.\nfunc (ar *allocRunner) Reconnect(update *structs.Allocation) (err error) {\n\tevent := structs.NewTaskEvent(structs.TaskClientReconnected)\n\tevent.Time = time.Now().UnixNano()\n\tfor _, tr := range ar.tasks {\n\t\ttr.AppendEvent(event)\n\t}\n\n\t// Update the client alloc with the server side indexes.\n\tar.setIndexes(update)\n\n\t// Calculate alloc state to get the final state with the new events.","sourceCodeStart":1475,"sourceCodeEnd":1511,"githubUrl":"https://github.com/hashicorp/nomad/blob/482b49bf1aec006f089bcfc7e632d8f6ac303e5e/client/allocrunner/alloc_runner.go#L1475-L1511","documentation":"When signaling all tasks in an allocation (empty taskName), allocRunner.Signal iterates every task runner and aggregates individual failures into a multierror, wrapping each as \"Failed to signal task: <name>, err: <cause>\". The error name of the failing task and underlying cause (e.g. task not running, driver error) are embedded in the message.","triggerScenarios":"Calling Signal with an empty taskName while one or more task runners fail tr.Signal — e.g. task is not running, driver cannot deliver the signal, or the driver does not support the signal.","commonSituations":"Group-wide signal during a deployment where one task crashed before the signal; signaling a group whose task driver (e.g. some exec drivers) cannot forward signals; signal sent while a task is mid-restart.","solutions":["Parse the task name from the multierror message and inspect the underlying cause for that task","Check task state with `nomad alloc status <alloc-id>` — wait for tasks to be running before signaling","Signal individual tasks by name to isolate which one fails and why","Retry the signal after the task restarts or becomes healthy"],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":"alloc, _, err := client.Allocations().Info(ctx, allocID, nil)\nif err == nil {\n  for tn, ts := range alloc.TaskStates {\n    if ts.State != structs.TaskStateRunning { log.Printf(\"task %s not running; signal may fail\", tn) }\n  }\n}","typeGuard":null,"tryCatchPattern":"if err := client.Allocations().Signal(ctx, allocID, \"\", sig); err != nil {\n  var merr *multierror.Error\n  if errors.As(err, &merr) {\n    for _, e := range merr.Errors { log.Printf(\"signal sub-failure: %v\", e) }\n  }\n}","preventionTips":["Check all task states are Running before group-wide signals","Prefer per-task signaling to get isolated failures","Retry after transient task restarts settle"],"tags":["nomad","client","signal","multierror"],"backgroundTag":"signal-delivery-failed","analyzedSha":"482b49bf1aec006f089bcfc7e632d8f6ac303e5e","analyzedAt":"2026-09-04T07:54:14.808Z","contentChangedAt":"2026-09-04T07:54:14.808Z","schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}