apache/hadoop · error · IOException

Exception while contacting value generator

Error message

Exception while contacting value generator 

What it means

Error "Exception while contacting value generator " thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/key/kms/ValueQueue.java:408

            numToFill = num - ekvs.size();
            break;
          }
          // Synchronous fill if not enough values found
          if (numToFill > 0) {
            refiller.fillQueueForKey(keyName, ekvs, numToFill);
          }

          break;
        } else {
          ekvs.add(val);
        }
      }
      // Schedule a refill task in case queue has gone below the watermark
      if (keyQueue.size() < (int) (lowWatermark * numValues)) {
        submitRefillTask(keyName, keyQueue);
      }
    } catch (Exception e) {
      throw new IOException("Exception while contacting value generator ", e);
    }
    return ekvs;
  }

  private void submitRefillTask(final String keyName,
      final Queue<E> keyQueue) throws InterruptedException {
    if (!executorThreadsStarted) {
      synchronized (this) {
        if (!executorThreadsStarted) {
          // To ensure all requests are first queued, make coreThreads =
          // maxThreads
          // and pre-start all the Core Threads.
          executor.prestartAllCoreThreads();
          executorThreadsStarted = true;
        }
      }
    }
    // The submit/execute method of the ThreadPoolExecutor is bypassed and

View on GitHub (pinned to 2add963021)

Solutions

1. The background refill thread could not contact the KMS value generator; check KMS availability and credentials.

Example fix

Check KMS server health and auth for the EEK operations.

When it happens

Trigger: Raised at runtime when the documented precondition or configuration requirement for this operation is violated.

Common situations: Misconfigured or missing property, invalid user input, or calling the API before its prerequisites are met.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/e071cffc7c6435f2. Report an issue: GitHub.