t8y2/dbx · error

resolve Kerberos server name for Cassandra host %s; configur

Error message

resolve Kerberos server name for Cassandra host %s; configure kerberosservername explicitly

What it means

Returned by kerberosServerName when the SPN host could not be derived for the given Cassandra host: reverse DNS (LookupAddr) and hostname extraction both failed, and no kerberosservername override is set. The service principal name for the KDC request cannot be formed, so Kerberos auth setup fails; the message names the host and suggests configuring kerberosservername explicitly.

Source

Thrown at agents/drivers/cassandra-go/kerberos.go:439

func kerberosServerName(config kerberosConfig, host *gocql.HostInfo) (string, error) {
	if config.serverName != "" {
		return strings.TrimSuffix(strings.TrimSpace(config.serverName), "."), nil
	}
	if host == nil {
		return "", fmt.Errorf("resolve Kerberos server name: Cassandra host is unavailable")
	}
	address := host.ConnectAddress()
	if address != nil {
		names, err := net.LookupAddr(address.String())
		if err == nil && len(names) > 0 {
			return strings.TrimSuffix(strings.TrimSpace(names[0]), "."), nil
		}
	}
	hostname, _, err := net.SplitHostPort(host.HostnameAndPort())
	if err == nil && hostname != "" && net.ParseIP(hostname) == nil {
		return strings.TrimSuffix(hostname, "."), nil
	}
	return "", fmt.Errorf("resolve Kerberos server name for Cassandra host %s; configure kerberosservername explicitly", host.ConnectAddressAndPort())
}

func (config *kerberosConfig) applyJavaSystemProperties() {
	if config.jaasConfigPath == "" {
		config.jaasConfigPath = javaSystemProperty("java.security.auth.login.config")
	}
	if config.configPath == "" {
		config.configPath = javaSystemProperty("java.security.krb5.conf")
	}
}

func (config *kerberosConfig) applyKerberosConfigEnvironment() {
	if config.configPath == "" {
		config.configPath = os.Getenv("KRB5_CONFIG")
	}
}

func (config *kerberosConfig) applyJAASConfig(path string) error {

View on GitHub (pinned to c0390bff16)

Solutions

1. Set kerberosservername in the connection config to the broker's FQDN matching its Kerberos principal
2. Fix DNS so the Cassandra host's IP reverse-resolves (PTR record) or its reported hostname is parseable as host:port

When it happens

Trigger: Thrown at agents/drivers/cassandra-go/kerberos.go:439 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of t8y2/dbx@c0390bff16 (2026-09-05). Data as JSON: /api/errors/be5028e1f9fdeb1d. Report an issue: GitHub.