apache/hadoop · error · RuntimeException

missing task ID

Error message

missing task ID

What it means

requireTask guards task-scoped pages of the AM web UI: it needs the 'task.id' query parameter holding a full task id (task_<ts>_<seq>_[m|r]_<n>). When the value is missing or empty the page answers 400 (badRequest) and this RuntimeException aborts rendering.

Source

Thrown at hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/webapp/AppController.java:439

    /* check for acl access */
    Job job = app.context.getJob(jobID);
    if (!checkAccess(job)) {
      accessDenied("User " + request().getRemoteUser() + " does not have " +
          " permission to view job " + $(JOB_ID));
      throw new RuntimeException("Access denied: User " +
          request().getRemoteUser() + " does not have permission to view job " +
          $(JOB_ID));
    }
  }

  /**
   * Ensure that a TASK_ID was passed into the page.
   */
  public void requireTask() {
    if ($(TASK_ID).isEmpty()) {
      badRequest("missing task ID");
      throw new RuntimeException("missing task ID");
    }

    TaskId taskID = MRApps.toTaskID($(TASK_ID));
    Job job = app.context.getJob(taskID.getJobId());
    app.setJob(job);
    if (app.getJob() == null) {
      notFound(MRApps.toString(taskID.getJobId()));
      throw new RuntimeException("Not Found: " + $(JOB_ID));
    } else {
      app.setTask(app.getJob().getTask(taskID));
      if (app.getTask() == null) {
        notFound($(TASK_ID));
        throw new RuntimeException("Not Found: " + $(TASK_ID));
      }
    }
    if (!checkAccess(job)) {
      accessDenied("User " + request().getRemoteUser() + " does not have " +
          " permission to view job " + $(JOB_ID));

View on GitHub (pinned to 2add963021)

Solutions

1. Append the full task id: /task?job.id=job_...&task.id=task_1401318629735_0001_m_000003
2. Open the job's task list page first and follow the generated links
3. Check that templating did not swallow the query string

Example fix

// before
http://am-host:8099/task?job.id=job_1401318629735_0001
// 400 missing task ID

// after
http://am-host:8099/task?job.id=job_1401318629735_0001&task.id=task_1401318629735_0001_m_000003

if (taskId == null || taskId.isEmpty() || !taskId.startsWith("task_")) {
  throw new IllegalArgumentException(
      "task.id query parameter is required: ?task.id=task_<ts>_<seq>_[m|r]_<n>");
}
String url = amUrl + "/task?job.id=" + enc(jobId) + "&task.id=" + enc(taskId);

static boolean isCompleteTaskUrl(String jobId, String taskId) {
  return jobId != null && !jobId.isEmpty()
      && taskId != null && taskId.startsWith("task_");
}

When it happens

Trigger: Opening /task without ?task.id=task_..., or with an empty value; typically also missing job.id (that check runs first in some pages, task.id here).

Common situations: URL truncated when shared; scraping scripts that forget the parameter; links built from partial job data.

Related errors

• missing task-type.
• missing attempt-state.
• Bad Request: Missing job ID
• taskid {} not found or invalid
• task not found with id {}

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/95555729a55a5c53. Report an issue: GitHub.