apache/hadoop · error · IOException

{} doesn't exist in mount table.

Error message

{} doesn't exist in mount table.

What it means

After argument validation, updateQuota queries the Router's mount table (getMountTableEntries) and looks for an entry whose sourcePath string-equals the path you passed. No exact match means the mount you tried to modify does not exist (as written), and the command fails with IOException '<path> doesn't exist in mount table.' before any quota update is sent.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/tools/federation/RouterAdmin.java:1107

  private boolean updateQuota(String mount, long nsQuota, long ssQuota)
      throws IOException {
    // Get existing entry
    MountTableManager mountTable = client.getMountTableManager();
    GetMountTableEntriesRequest getRequest = GetMountTableEntriesRequest
        .newInstance(mount);
    GetMountTableEntriesResponse getResponse = mountTable
        .getMountTableEntries(getRequest);
    List<MountTable> results = getResponse.getEntries();
    MountTable existingEntry = null;
    for (MountTable result : results) {
      if (mount.equals(result.getSourcePath())) {
        existingEntry = result;
        break;
      }
    }

    if (existingEntry == null) {
      throw new IOException(mount + " doesn't exist in mount table.");
    } else {
      long nsCount = existingEntry.getQuota().getFileAndDirectoryCount();
      long ssCount = existingEntry.getQuota().getSpaceConsumed();
      // If nsQuota and ssQuota were reset, clear nsQuota and ssQuota.
      if (nsQuota == HdfsConstants.QUOTA_RESET &&
          ssQuota == HdfsConstants.QUOTA_RESET) {
        nsCount = RouterQuotaUsage.QUOTA_USAGE_COUNT_DEFAULT;
        ssCount = RouterQuotaUsage.QUOTA_USAGE_COUNT_DEFAULT;
      } else {
        // If nsQuota or ssQuota was unset, use the value in mount table.
        if (nsQuota == HdfsConstants.QUOTA_DONT_SET) {
          nsQuota = existingEntry.getQuota().getQuota();
        }
        if (ssQuota == HdfsConstants.QUOTA_DONT_SET) {
          ssQuota = existingEntry.getQuota().getSpaceQuota();
        }
      }

View on GitHub (pinned to 2add963021)

Solutions

1. List actual mounts and copy the exact path: hdfs dfsrouteradmin -ls / (exact string, leading slash, no trailing slash)
2. Create the mount first if missing: hdfs dfsrouteradmin -add /data ns1 /data
3. Confirm you are talking to the right Router (dfs.federation.router.rpc-address in the client config) and that its state store is loaded
4. If the state store was just modified, allow the Router cache refresh interval to pass or restart the Router

Example fix

# before
hdfs dfsrouteradmin -setQuota /data/ -nsQuota 100000   # trailing slash -> not found
# after
hdfs dfsrouteradmin -setQuota /data -nsQuota 100000

# confirm exact mount-path match before setting a quota
MOUNTS=$(hdfs dfsrouteradmin -ls / 2>/dev/null | awk '{print $1}')
echo "$MOUNTS" | grep -qx "$MOUNT_PATH" || { echo "mount '$MOUNT_PATH' not in mount table (exact string match required)" >&2; exit 2; }
hdfs dfsrouteradmin -setQuota "$MOUNT_PATH" -nsQuota "$NS"

Catch IOException around updateQuota calls in Java Router clients and distinguish the 'doesn't exist in mount table' message from RPC connectivity failures before retrying.

When it happens

Trigger: -setQuota /dat (typo for /data); a mount never created (missing -add step); trailing slash '/data/' vs registered '/data'; connecting to a Router whose state store has no such entry (wrong router, state store not synced, or Router freshly started and cache empty); missing leading slash.

Common situations: New RBF deployments where mounts live in a different Router's state store; CI environments rebuilt without mount entries; path-normalization mismatches between runbooks and the actual mount table.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• The operation is not allowed because there are mount points:
• Cannot find locations for {} in {}
• {} is in a read only mount point
• Cannot parse nsQuota: {}
• Cannot parse ssQuota: {}

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/e83fc68cee0e15c2. Report an issue: GitHub.