apache/hadoop · error · IOException

realuser is too long to be serialized!

Error message

realuser is too long to be serialized!

What it means

Error "realuser is too long to be serialized!" thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/token/delegation/AbstractDelegationTokenIdentifier.java:226

    owner.write(out);
    renewer.write(out);
    realUser.write(out);
    WritableUtils.writeVLong(out, issueDate);
    WritableUtils.writeVLong(out, maxDate);
    WritableUtils.writeVInt(out, sequenceNumber);
    WritableUtils.writeVInt(out, masterKeyId);
  }
  
  @Override
  public void write(DataOutput out) throws IOException {
    if (owner.getLength() > Text.DEFAULT_MAX_LEN) {
      throw new IOException("owner is too long to be serialized!");
    }
    if (renewer.getLength() > Text.DEFAULT_MAX_LEN) {
      throw new IOException("renewer is too long to be serialized!");
    }
    if (realUser.getLength() > Text.DEFAULT_MAX_LEN) {
      throw new IOException("realuser is too long to be serialized!");
    }
    writeImpl(out);
  }
  
  @Override
  public String toString() {
    StringBuilder buffer = new StringBuilder();
    buffer
        .append(getKind())
        .append(" owner=").append(owner)
        .append(", renewer=").append(renewer)
        .append(", realUser=").append(realUser)
        .append(", issueDate=").append(issueDate)
        .append(", maxDate=").append(maxDate)
        .append(", sequenceNumber=").append(sequenceNumber)
        .append(", masterKeyId=").append(masterKeyId);
    return buffer.toString();
  }

View on GitHub (pinned to 2add963021)

Solutions

1. Shorten the real user name: for proxy-user tokens the realUser field exceeds the maximum serializable length. Use a shorter user name for the proxied identity.

When it happens

Trigger: Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/token/delegation/AbstractDelegationTokenIdentifier.java:226 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/993470916d08c39c. Report an issue: GitHub.