k3s-io/k3s · error

invalid cluster-dns address %s

Error message

invalid cluster-dns address %s

What it means

Error "invalid cluster-dns address %s" thrown in k3s-io/k3s.

Source

Thrown at pkg/cli/server/server.go:367

	serverConfig.ControlConfig.SANs = append(serverConfig.ControlConfig.SANs, apiServerServiceIP.String())

	// If cluster-dns CLI arg is not set, we set ClusterDNS address to be the first IPv4 ServiceCIDR network + 10,
	// i.e. when you set service-cidr to 192.168.0.0/16 and don't provide cluster-dns, it will be set to 192.168.0.10
	// If there are no IPv4 ServiceCIDRs, an IPv6 ServiceCIDRs will be used.
	// If neither of IPv4 or IPv6 are found an error is raised.
	if len(cmds.ServerConfig.ClusterDNS.Value()) == 0 {
		for _, svcCIDR := range serverConfig.ControlConfig.ServiceIPRanges {
			clusterDNS, err := utilsnet.GetIndexedIP(svcCIDR, 10)
			if err != nil {
				return errors.WithMessage(err, "cannot configure default cluster-dns address")
			}
			serverConfig.ControlConfig.ClusterDNSs = append(serverConfig.ControlConfig.ClusterDNSs, clusterDNS)
		}
	} else {
		for _, ip := range util.SplitStringSlice(cmds.ServerConfig.ClusterDNS.Value()) {
			parsed := net.ParseIP(ip)
			if parsed == nil {
				return fmt.Errorf("invalid cluster-dns address %s", ip)
			}
			serverConfig.ControlConfig.ClusterDNSs = append(serverConfig.ControlConfig.ClusterDNSs, parsed)
		}
	}

	serverConfig.ControlConfig.ClusterDNS = serverConfig.ControlConfig.ClusterDNSs[0]

	if err := validateNetworkConfiguration(serverConfig); err != nil {
		return err
	}

	if cfg.DefaultLocalStoragePath == "" {
		dataDir, err := datadir.LocalHome(cfg.DataDir, false)
		if err != nil {
			return err
		}
		serverConfig.ControlConfig.DefaultLocalStoragePath = filepath.Join(dataDir, "/storage")
	} else {

View on GitHub (pinned to 6ba341e396)

When it happens

Trigger: Thrown at pkg/cli/server/server.go:367 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of k3s-io/k3s@6ba341e396 (2026-08-15). Data as JSON: /api/errors/c4c0f45c74622a0f. Report an issue: GitHub.