)

	// pilot_total_xds_rejects should be used instead. This is for backwards compatibility
	cdsReject = monitoring.NewGauge(
		"pilot_xds_cds_reject",
		"Pilot rejected CDS configs.",
	)

	// pilot_total_xds_rejects should be used instead. This is for backwards compatibility
	edsReject = monitoring.NewGauge(
		"pilot_xds_eds_reject",
		"Pilot rejected EDS.",
	)

	OrphanPodCleanedVolumesErrors = metrics.NewGauge(
		&metrics.GaugeOpts{
			Subsystem:      KubeletSubsystem,
			Name:           orphanPodCleanedVolumesErrorsKey,
			Help:           "The number of orphaned Pods whose volumes failed to be cleaned in the last periodic sweep.",
			StabilityLevel: metrics.ALPHA,
		},
	)

	NodeStartupPreKubeletDuration = metrics.NewGauge(
		&metrics.GaugeOpts{

			StabilityLevel: metrics.ALPHA,
		},
	)

	// SyncProxyRulesLastTimestamp is the timestamp proxy rules were last
	// successfully synced.
	SyncProxyRulesLastTimestamp = metrics.NewGauge(
		&metrics.GaugeOpts{
			Subsystem:      kubeProxySubsystem,
			Name:           "sync_proxy_rules_last_timestamp_seconds",
			Help:           "The last time proxy rules were successfully synced",

	)

	successCounts = monitoring.NewSum(
		"citadel_server_success_cert_issuance_count",
		"The number of certificates issuances that have succeeded.",
	)

	rootCertExpiryTimestamp = monitoring.NewGauge(
		"citadel_server_root_cert_expiry_timestamp",
		"The unix timestamp, in seconds, when Citadel root cert will expire. "+
			"A negative time indicates the cert is expired.",
	)

	versionTag = monitoring.CreateLabel("version")

	monServices = monitoring.NewGauge(
		"pilot_services",
		"Total services known to pilot.",
	)

	// TODO: Update all the resource stats in separate routine
	// virtual services, destination rules, gateways, etc.
	xdsClients = monitoring.NewGauge(
		"pilot_xds",
		"Number of endpoints connected to this pilot using XDS.",
	)

	VirtualHost PatchType = "vhost"
)

var (
	patchType  = monitoring.CreateLabel("patch")
	resultType = monitoring.CreateLabel("result")
	nameType   = monitoring.CreateLabel("name")

	envoyFilterStatus = monitoring.NewGauge(
		"pilot_envoy_filter_status",
		"Status of Envoy filters whether it was applied or errored.",
		monitoring.WithEnabled(func() bool {
			return features.EnableEnvoyFilterMetrics
		}),
	)
)

var (

		"Current istiod server uptime in seconds",
	).ValueFrom(func() float64 {
		return time.Since(serverStart).Seconds()
	})

	versionTag   = monitoring.CreateLabel("version")
	pilotVersion = monitoring.NewGauge(
		"pilot_info",
		"Pilot version and build information.",
	)
)

func init() {
	pilotVersion.With(versionTag.Value(version.Info.String())).Record(1)
}

func addMonitor(mux *http.ServeMux) error {

		"xds_cache_evictions",
		"Total number of xds cache evictions.",
		monitoring.WithEnabled(enableStats),
	)

	xdsCacheSize = monitoring.NewGauge(
		"xds_cache_size",
		"Current size of xds cache",
		monitoring.WithEnabled(enableStats),
	)

	dependentConfigSize = monitoring.NewGauge(
		"xds_cache_dependent_config_size",
		"Current size of dependent configs",
		monitoring.WithEnabled(enableStats),
	)

	ProxyStatusNoService = monitoring.NewGauge(
		"pilot_no_ip",
		"Pods not found in the endpoint table, possibly invalid.",
	)

	// ProxyStatusEndpointNotReady represents proxies found not be ready.
	// Updated by GetProxyServiceTargets. Normal condition when starting
	// an app with readiness, error if it doesn't change to 0.
	ProxyStatusEndpointNotReady = monitoring.NewGauge(
		"pilot_endpoint_not_ready",

	"istio.io/istio/pkg/monitoring"
	"istio.io/istio/pkg/zdsapi"
)

var (
	ztunnelKeepAliveCheckInterval = 5 * time.Second
	readWriteDeadline             = 5 * time.Second
)

var ztunnelConnected = monitoring.NewGauge("ztunnel_connected",
	"number of connections to ztunnel")

type ZtunnelServer interface {
	Run(ctx context.Context)
	PodDeleted(ctx context.Context, uid string) error