apache/hadoop · error · BadFencingConfigurationException

Unable to parse user and SSH port: {}

Error message

Unable to parse user and SSH port: {}

What it means

SshFenceByTcpPort.Args throws BadFencingConfigurationException('Unable to parse user and SSH port: <arg>') when the sshfence argument does not match USER_PORT_RE — pattern '([^:]+?)?(?:\:(\d+))?' i.e. an optional colon-free username and an optional colon-prefixed numeric port.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ha/SshFenceByTcpPort.java:246

  static class Args {
    private static final Pattern USER_PORT_RE = Pattern.compile(
      "([^:]+?)?(?:\\:(\\d+))?");

    private static final int DEFAULT_SSH_PORT = 22;

    String user;
    int sshPort;
    
    public Args(String arg) 
        throws BadFencingConfigurationException {
      user = System.getProperty("user.name");
      sshPort = DEFAULT_SSH_PORT;

      // Parse optional user and ssh port
      if (arg != null && !arg.isEmpty()) {
        Matcher m = USER_PORT_RE.matcher(arg);
        if (!m.matches()) {
          throw new BadFencingConfigurationException(
              "Unable to parse user and SSH port: "+ arg);
        }
        if (m.group(1) != null) {
          user = m.group(1);
        }
        if (m.group(2) != null) {
          sshPort = parseConfiggedPort(m.group(2));
        }
      }
    }

    private int parseConfiggedPort(String portStr)
        throws BadFencingConfigurationException {
      try {
        return Integer.parseInt(portStr);
      } catch (NumberFormatException nfe) {
        throw new BadFencingConfigurationException(
            "Port number '" + portStr + "' invalid");

View on GitHub (pinned to 2add963021)

Solutions

1. Use the exact form 'sshfence(<user>:<port>)' with a plain username and a decimal port, e.g. 'sshfence(hdfs:22)'.
2. Omit parts entirely ('sshfence(hdfs)' or 'sshfence(:2222)') rather than adding placeholders — user.name and port 22 are the defaults.
3. Remove all spaces and extra colons from the argument.

Example fix

<!-- before: hostname wrongly placed in the arg, extra colon -->
<value>sshfence(root@nn1:22)</value>

<!-- after: username:port only; host is derived from the service address -->
<value>sshfence(root:22)</value>

// Same rule as USER_PORT_RE: optional colon-free user, optional ':<digits>'
if (arg != null && !arg.isEmpty() && !arg.matches("([^:]+?)?(?::(\\d+))?")) {
  throw new IllegalArgumentException("Bad sshfence arg: " + arg);
}

try {
  new NodeFencer(conf, "sshfence(" + arg + ")");
} catch (BadFencingConfigurationException e) {
  // 'Unable to parse user and SSH port' -> fix arg to user:port form
}

When it happens

Trigger: An sshfence(...) entry whose argument has a non-numeric port, spaces, or multiple colons: 'sshfence(hdfs:twentyTwo)', 'sshfence(hdfs :22)', 'sshfence(root:22:33)'. Valid forms are 'sshfence()', 'sshfence(hdfs)', 'sshfence(:2022)', 'sshfence(hdfs:22)'.

Common situations: Putting a hostname in the argument (the target host comes from the service address, not this arg); user names containing ':' or '@'; placeholder text left in templated config; port written with whitespace or units.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• Unable to parse line: '{}'
• Port number '{}' invalid
• Unable to fence {}. Fencing failed.
• Could not find configured fencing method {}
• Class {} does not implement FenceMethod

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/e86de6400f5c6571. Report an issue: GitHub.