apache/hadoop · error · RuntimeException

Bad EC policy configuration file: no <policies> element

Error message

Bad EC policy configuration file: no <policies> element

What it means

Inside <configuration>, ECPolicyLoader validates three sections in order: <layoutversion>, then <schemas>, then <policies>. If layoutversion matches and schemas exist but no <policies> element is present - the element that actually carries the list of policy entries - loading aborts with 'Bad EC policy configuration file: no <policies> element'. The container validated fine but the payload is missing.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/util/ECPolicyLoader.java:111

    dbf.setIgnoringComments(true);
    DocumentBuilder builder = dbf.newDocumentBuilder();
    Document doc = builder.parse(policyFile);
    Element root = doc.getDocumentElement();

    if (!"configuration".equals(root.getTagName())) {
      throw new RuntimeException("Bad EC policy configuration file: "
          + "top-level element not <configuration>");
    }

    List<ErasureCodingPolicy> policies;
    if (root.getElementsByTagName("layoutversion").getLength() > 0) {
      if (loadLayoutVersion(root) == LAYOUT_VERSION) {
        if (root.getElementsByTagName("schemas").getLength() > 0) {
          Map<String, ECSchema> schemas = loadSchemas(root);
          if (root.getElementsByTagName("policies").getLength() > 0) {
            policies = loadPolicies(root, schemas);
          } else {
            throw new RuntimeException("Bad EC policy configuration file: "
                + "no <policies> element");
          }
        } else {
          throw new RuntimeException("Bad EC policy configuration file: "
              + "no <schemas> element");
        }
      } else {
        throw new RuntimeException("The parse failed because of "
            + "bad layoutversion value");
      }
    } else {
      throw new RuntimeException("Bad EC policy configuration file: "
          + "no <layoutVersion> element");
    }

    return policies;
  }

View on GitHub (pinned to 2add963021)

Solutions

1. Add a <policies> element containing one <policy> entry per EC policy you want to add
2. Check spelling and case - the loader matches the literal lowercase tag 'policies'
3. Model the file on the shipped user-ec-policies.xml example

Example fix

<!-- before: layoutversion + schemas only -->
<configuration>
  <layoutversion>1</layoutversion>
  <schemas>...</schemas>
</configuration>

<!-- after -->
<configuration>
  <layoutversion>1</layoutversion>
  <schemas>...</schemas>
  <policies>
    <policy><name>MY-POLICY</name><!-- schemaId, cellsize... --></policy>
  </policies>
</configuration>

Element root = doc.getDocumentElement();
boolean hasPolicies = root.getElementsByTagName("policies").getLength() > 0;
if (!hasPolicies) { /* reject before loadPolicy */ }

try {
  new ECPolicyLoader().loadPolicy(path);
} catch (RuntimeException e) {
  if (e.getMessage() != null && e.getMessage().contains("no <policies> element")) {
    // add a <policies> block with <policy> entries and retry
  } else { throw e; }
}

When it happens

Trigger: `hdfs ec -addPolicies` with a file that has <layoutversion> and <schemas> but no <policies> element: the block was deleted, commented out, or misspelled (e.g. <policy> or <Policies>).

Common situations: Typos in element names; blocks commented out during debugging; templates trimmed too aggressively.

Related errors

• Bad EC policy configuration file: no <schemas> element
• Bad EC policy configuration file: top-level element not <con
• Bad element in EC policy configuration file: {tagName}
• Value of <{tagName}> is null
• Bad policy is found in EC policy configuration file

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/197f19549feb7bba. Report an issue: GitHub.