thanos-io/thanos · error

Address is not of : format or a valid DNS query.

Error message

Address %s is not of <host>:<port> format or a valid DNS query.

What it means

validateAddrs checks that every address passed to a DNS-resolving flag is either a <host>:<port> pair or a DNS query of the form <qtype>+<name>. If an address splits into neither a host:port (no colon) nor a qtype+name (no plus), this error is thrown. It is a client-side validation performed before the address is ever used.

Solutions

1. Append the port to the address, e.g. 'thanos-store:9090'.
2. For SRV lookups use the '<qtype>+<name>' form, e.g. '_grpc._tcp.thanos-store.example.com' prefixed like 'dnssrv+_grpc._tcp.myservice'.
3. Verify the flag value contains either a ':' (host:port) or a '+' (DNS query) before starting Thanos.

Example fix

// before
--store=dnssrv+_http._tcp.thanos-store
// after
--store=dnssrv+_grpc._tcp.thanos-store:9090

func validAddr(a string) bool { return strings.Contains(a, ":") || strings.Contains(a, "+") }
if !validAddr(addr) { return fmt.Errorf("bad address %q", addr) }

When it happens

Trigger: Calling Set (via flags like --store, --sidecars, --ruler, --query) with an address lacking both ':' and '+' separators, e.g. 'thanos-store' without a port, or 'localhost:9090+dnssrv' malformed so SplitN yields only one part.

Common situations: Copy-pasting a service name without its port from Kubernetes docs; forgetting the port on a store address; hand-typing a DNS SRV query and omitting the '+' between qtype and name.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

• DNS resolution errors: ENOTFOUND and getaddrinfo failures — how hostname lookups fail and how to debug them.

Related errors

• unsupported format for label
• --auto-gomemlimit.ratio must be greater than 0 and less…
• error validating the config
• --receive.lazy-retrieval-max-buffered-responses must be > 0
• Address is duplicated for --query flag.

AI-assisted analysis of thanos-io/thanos@35b8b99117 (2026-09-07). Data as JSON: /api/errors/ffd7918dbc7d7006. Report an issue: GitHub.

Appendix: source

Thrown at pkg/extkingpin/flags.go:60

}

func Addrs(flags *kingpin.FlagClause) (target *addressSlice) {
	target = &addressSlice{}
	flags.SetValue((*addressSlice)(target))
	return
}

// validateAddrs checks an address slice for empty or invalid elements.
func validateAddrs(addrs addressSlice) error {
	for _, addr := range addrs {
		if addr == "" {
			return errors.New("Address is empty.")
		}

		qtypeAndName := strings.SplitN(addr, "+", 2)
		hostAndPort := strings.SplitN(addr, ":", 2)
		if len(qtypeAndName) != 2 && len(hostAndPort) != 2 {
			return errors.Errorf("Address %s is not of <host>:<port> format or a valid DNS query.", addr)
		}
	}

	return nil
}

// RegisterHTTPFlags register flags commonly used to configure http servers with.
func RegisterHTTPFlags(cmd FlagClause) (httpBindAddr *string, httpGracePeriod *model.Duration, httpTLSConfig *string) {
	httpBindAddr = cmd.Flag("http-address", "Listen host:port for HTTP endpoints.").Default("0.0.0.0:10902").String()
	httpGracePeriod = ModelDuration(cmd.Flag("http-grace-period", "Time to wait after an interrupt received for HTTP Server.").Default("2m")) // by default it's the same as query.timeout.
	httpTLSConfig = cmd.Flag(
		"http.config",
		"[EXPERIMENTAL] Path to the configuration file that can enable TLS or authentication for all HTTP endpoints.",
	).Default("").String()
	return httpBindAddr, httpGracePeriod, httpTLSConfig
}

// RegisterCommonObjStoreFlags register flags to specify object storage configuration.

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