apache/flink · error · IOException

The given file system URI (${fsUri}) did not describe the au

Error message

The given file system URI (${fsUri}) did not describe the authority (like for example HDFS NameNode address/port or S3 host). The attempt to use a configured default authority failed: The configuration contains an invalid file system default name ('fs.default.name' or 'fs.defaultFS'): ${configEntry}

What it means

While resolving a missing authority via the default filesystem config, fs.defaultFS (or deprecated fs.default.name) exists but its value is not a parseable URI: java.net.URI.create throws IllegalArgumentException, which HadoopFsFactory wraps in this IOException. The config entry is syntactically invalid (bad characters, malformed scheme, spaces).

Source

Thrown at flink-filesystems/flink-hadoop-fs/src/main/java/org/apache/flink/runtime/fs/hdfs/HadoopFsFactory.java:149

                if (configEntry == null) {
                    // fs.default.name deprecated as of hadoop 2.2.0 - see
                    // http://hadoop.apache.org/docs/current/hadoop-project-dist/hadoop-common/DeprecatedProperties.html
                    configEntry = hadoopConfig.get("fs.default.name", null);
                }

                if (LOG.isDebugEnabled()) {
                    LOG.debug("Hadoop's 'fs.defaultFS' is set to {}", configEntry);
                }

                if (configEntry == null) {
                    throw new IOException(
                            getMissingAuthorityErrorPrefix(fsUri)
                                    + "Hadoop configuration did not contain an entry for the default file system ('fs.defaultFS').");
                } else {
                    try {
                        initUri = URI.create(configEntry);
                    } catch (IllegalArgumentException e) {
                        throw new IOException(
                                getMissingAuthorityErrorPrefix(fsUri)
                                        + "The configuration contains an invalid file system default name "
                                        + "('fs.default.name' or 'fs.defaultFS'): "
                                        + configEntry);
                    }

                    if (initUri.getAuthority() == null) {
                        throw new IOException(
                                getMissingAuthorityErrorPrefix(fsUri)
                                        + "Hadoop configuration for default file system ('fs.default.name' or 'fs.defaultFS') "
                                        + "contains no valid authority component (like hdfs namenode, S3 host, etc)");
                    }
                }
            }

            // -- (5) configure the Hadoop file system

            try {

View on GitHub (pinned to 2f3c205e92)

Solutions

Correct the fs.defaultFS value to a valid URI, e.g. hdfs://namenode:8020
Check for stray whitespace, quotes, or unresolved ${VAR} placeholders in core-site.xml / flink-conf.yaml
After fixing, verify with a URI parse test or by running hdfs getconf -confKey fs.defaultFS

Example fix

<!-- before --><property><name>fs.defaultFS</name><value>hdfs: namenode:8020</value></property>
<!-- after --><property><name>fs.defaultFS</name><value>hdfs://namenode:8020</value></property>

Defensive patterns

Strategy: validation

Validate before calling

String def = conf.get("fs.defaultFS");
if (def != null) {
    try {
        URI.create(def.trim());
    } catch (IllegalArgumentException e) {
        throw new IllegalStateException("fs.defaultFS is not a valid URI: '" + def + "'");
    }
}

Try / catch

try {
    fs = FileSystem.get(uri);
} catch (IOException e) {
    if (e.getMessage().contains("invalid file system default name")) {
        // fix the fs.defaultFS string in core-site.xml / flink-conf.yaml
    }
}

Prevention

Lint configuration files for invalid URI values before deploy
Avoid hand-editing hostnames into XML; template them from one source
Watch for whitespace and unresolved placeholders after env substitution

When it happens

Trigger: fs.defaultFS set to a value like 'hdfs: namenode:8020' or 'my namenode' (unparseable); URI.create(configEntry) throws inside HadoopFsFactory.create when the original fsUri lacked an authority.

Common situations: Typos in core-site.xml or flink-conf.yaml; values pasted with quotes/spaces; environment variable substitution producing empty or malformed strings in containerized deployments.

Related errors

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/fbb1e4c6daa574e7. Report an issue: GitHub.