apache/hadoop · error · InvalidRequestException

Cache pool poolName already exists.

Error message

Cache pool poolName already exists.

What it means

Error "Cache pool poolName already exists." thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/CacheManager.java:826

  /**
   * Create a cache pool.
   * 
   * Only the superuser should be able to call this function.
   *
   * @param info    The info for the cache pool to create.
   * @return        Information about the cache pool we created.
   */
  public CachePoolInfo addCachePool(CachePoolInfo info)
      throws IOException {
    assert namesystem.hasWriteLock(RwLockMode.FS);
    CachePool pool;
    try {
      CachePoolInfo.validate(info);
      String poolName = info.getPoolName();
      pool = cachePools.get(poolName);
      if (pool != null) {
        throw new InvalidRequestException("Cache pool " + poolName
            + " already exists.");
      }
      pool = CachePool.createFromInfoAndDefaults(info);
      cachePools.put(pool.getPoolName(), pool);
    } catch (IOException e) {
      LOG.info("addCachePool of " + info + " failed: ", e);
      throw e;
    }
    LOG.info("addCachePool of {} successful.", info);
    return pool.getInfo(true);
  }

  /**
   * Modify a cache pool.
   * 
   * Only the superuser should be able to call this function.
   *
   * @param info

View on GitHub (pinned to 2add963021)

Solutions

1. Use a different pool name, or modify the existing pool with hdfs cacheadmin -modifyPool.

When it happens

Trigger: addCachePool with a pool name that already exists.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/602b7eda07fc19d5. Report an issue: GitHub.