public static Cluster open(final String configurationFile) throws Exception {
        final File systemFile = new File(configurationFile);
        if (!systemFile.exists()) {
            final ClassLoader currentClassLoader = Thread.currentThread().getContextClassLoader();
            final URL resource = currentClassLoader.getResource(configurationFile);
            final File resourceFile = new File(resource.getFile());
            if (!resourceFile.exists()) {
                throw new IllegalArgumentException(String.format("Configuration file at %s does not exist", configurationFile));
            }

            return build(resourceFile).create();
        }

        return build(systemFile).create();
    }
Create a {@code Cluster} using a YAML-based configuration file.
First try to read the file from the file system and then from resources.
gremlin-driver/src/main/java/org/apache/tinkerpop/gremlin/driver/Cluster.java