@Override
    protected Void callInternal() {
      try {
        amNodeInfo.getUmbilical().taskKilled(taskAttemptId);
      } catch (IOException e) {
        LOG.warn("Failed to send taskKilled message for task {}. Will re-run after it times out", taskAttemptId);
      } catch (InterruptedException e) {
        if (!isShutdown.get()) {
          LOG.info("Interrupted while trying to send taskKilled message for task {}", taskAttemptId);
        }
      }
      return null;
    }
Responsible for communicating with various AMs.
llap-server/src/java/org/apache/hadoop/hive/llap/daemon/impl/AMReporter.java