apache/hadoop · error · IllegalArgumentException

No value for {key} found in conf file.

Error message

No value for {key} found in conf file.

What it means

Utils.notNull(Configuration, key) is the oauth2 module's required-configuration guard: it throws IllegalArgumentException('No value for <key> found in conf file.') when conf.get(key) returns null, naming the exact missing key. It runs inside setConf of the oauth2 AccessTokenProviders, so it fires as soon as a WebHDFS-with-OAuth2 filesystem is initialized, before any request is made. Keys guarded this way include dfs.webhdfs.oauth2.credential, dfs.webhdfs.oauth2.refresh.token, dfs.webhdfs.oauth2.client.id, and dfs.webhdfs.oauth2.refresh.url.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/web/oauth2/Utils.java:37

package org.apache.hadoop.hdfs.web.oauth2;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

@InterfaceAudience.Private
@InterfaceStability.Evolving
final class Utils {
  private Utils() { /* Private constructor */ }

  public static String notNull(Configuration conf, String key) {
    String value = conf.get(key);

    if(value == null) {
      throw new IllegalArgumentException("No value for " + key +
          " found in conf file.");
    }

    return value;
  }

  public static String postBody(String ... kv)
      throws UnsupportedEncodingException {
    if(kv.length % 2 != 0) {
      throw new IllegalArgumentException("Arguments must be key value pairs");
    }
    StringBuilder sb = new StringBuilder();
    int i = 0;

    while(i < kv.length) {
      if(i > 0) {
        sb.append("&");
      }

View on GitHub (pinned to 2add963021)

Solutions

1. Add the property named in the message to the client's configuration (core-site.xml or the Configuration object used to create the FileSystem)
2. Confirm the file is actually loaded (check -conf stack or conf.get after load) and the name matches byte-for-byte — no trailing spaces
3. Provide all keys the chosen provider requires: credential provider needs dfs.webhdfs.oauth2.credential + client.id + refresh.url; refresh-token provider additionally needs dfs.webhdfs.oauth2.refresh.token
4. Fail fast in your own bootstrap by asserting required keys before FileSystem.get()

Example fix

<!-- before: provider set, credential missing -->
<property>
  <name>dfs.webhdfs.oauth2.access.token.provider</name>
  <value>org.apache.hadoop.hdfs.web.oauth2.ConfCredentialBasedAccessTokenProvider</value>
</property>
<!-- after: add the key named in the message -->
<property>
  <name>dfs.webhdfs.oauth2.credential</name>
  <value>my-client-secret</value>
</property>

static final String[] OAUTH2_REQUIRED = {
    "dfs.webhdfs.oauth2.client.id",
    "dfs.webhdfs.oauth2.refresh.url"
    // plus provider-specific: dfs.webhdfs.oauth2.credential
    // or dfs.webhdfs.oauth2.refresh.token
};
for (String k : OAUTH2_REQUIRED) {
  if (conf.get(k) == null) {
    throw new IllegalStateException("Missing required OAuth2 config: " + k);
  }
}

When it happens

Trigger: Initializing WebHdfsFileSystem with dfs.webhdfs.oauth2.access.token.provider set to ConfCredentialBasedAccessTokenProvider / ConfRefreshTokenBasedAccessTokenProvider / CredentialBasedAccessTokenProvider while any of their required keys (named in the message) is absent from the client Configuration.

Common situations: Enabling OAuth2 for S3A-style WebHDFS deployments but only configuring the provider class; putting oauth2 keys in hdfs-site.xml while the client only loads core-site.xml; XML typo in the property name; keys set on the gateway but missing on client machines.

Related errors

• Unable to load OAuth2 connection factory.
• Credential has not been provided in configuration
• No more entry in " + f
• f + " already exists"
• Unsupported scheme: {}

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/d3aff03ef0dc1722. Report an issue: GitHub.