const (
	KubeletSubsystem             = "kubelet"
	PodWorkerLatencyKey          = "pod_worker_latency_microseconds"
	PodStartLatencyKey           = "pod_start_latency_microseconds"
	CgroupManagerOperationsKey   = "cgroup_manager_latency_microseconds"
	PodWorkerStartLatencyKey     = "pod_worker_start_latency_microseconds"
	PLEGRelistLatencyKey         = "pleg_relist_latency_microseconds"
	PLEGRelistIntervalKey        = "pleg_relist_interval_microseconds"
	EvictionStatsAgeKey          = "eviction_stats_age_microseconds"
	VolumeStatsCapacityBytesKey  = "volume_stats_capacity_bytes"
	VolumeStatsAvailableBytesKey = "volume_stats_available_bytes"
	VolumeStatsUsedBytesKey      = "volume_stats_used_bytes"
	VolumeStatsInodesKey         = "volume_stats_inodes"
	VolumeStatsInodesFreeKey     = "volume_stats_inodes_free"
	VolumeStatsInodesUsedKey     = "volume_stats_inodes_used"
	// Metrics keys of remote runtime operations
	RuntimeOperationsKey        = "runtime_operations"
	RuntimeOperationsLatencyKey = "runtime_operations_latency_microseconds"
	RuntimeOperationsErrorsKey  = "runtime_operations_errors"
	// Metrics keys of device plugin operations
	DevicePluginRegistrationCountKey = "device_plugin_registration_count"
	DevicePluginAllocationLatencyKey = "device_plugin_alloc_latency_microseconds"
)

var (
	ContainersPerPodCount = prometheus.NewSummary(
		prometheus.SummaryOpts{
			Subsystem: KubeletSubsystem,
			Name:      "containers_per_pod_count",
			Help:      "The number of containers per pod.",
		},
	)
	PodWorkerLatency = prometheus.NewSummaryVec(
		prometheus.SummaryOpts{
			Subsystem: KubeletSubsystem,
			Name:      PodWorkerLatencyKey,
			Help:      "Latency in microseconds to sync a single pod. Broken down by operation type: create, update, or sync",
		},
		[]string{"operation_type"},
	)
	PodStartLatency = prometheus.NewSummary(
		prometheus.SummaryOpts{
			Subsystem: KubeletSubsystem,
			Name:      PodStartLatencyKey,
			Help:      "Latency in microseconds for a single pod to go from pending to running. Broken down by podname.",
		},
	)
	CgroupManagerLatency = prometheus.NewSummaryVec(
		prometheus.SummaryOpts{
			Subsystem: KubeletSubsystem,
			Name:      CgroupManagerOperationsKey,
			Help:      "Latency in microseconds for cgroup manager operations. Broken down by method.",
		},
		[]string{"operation_type"},
	)
	PodWorkerStartLatency = prometheus.NewSummary(
		prometheus.SummaryOpts{
			Subsystem: KubeletSubsystem,
			Name:      PodWorkerStartLatencyKey,
			Help:      "Latency in microseconds from seeing a pod to starting a worker.",
		},
	)
	PLEGRelistLatency = prometheus.NewSummary(
		prometheus.SummaryOpts{
			Subsystem: KubeletSubsystem,
			Name:      PLEGRelistLatencyKey,
			Help:      "Latency in microseconds for relisting pods in PLEG.",
		},
	)
	PLEGRelistInterval = prometheus.NewSummary(
		prometheus.SummaryOpts{
			Subsystem: KubeletSubsystem,
			Name:      PLEGRelistIntervalKey,
			Help:      "Interval in microseconds between relisting in PLEG.",
		},
	)
	// Metrics of remote runtime operations.
	RuntimeOperations = prometheus.NewCounterVec(
		prometheus.CounterOpts{
			Subsystem: KubeletSubsystem,
			Name:      RuntimeOperationsKey,
			Help:      "Cumulative number of runtime operations by operation type.",
		},
		[]string{"operation_type"},
	)
	RuntimeOperationsLatency = prometheus.NewSummaryVec(
		prometheus.SummaryOpts{
			Subsystem: KubeletSubsystem,
			Name:      RuntimeOperationsLatencyKey,
			Help:      "Latency in microseconds of runtime operations. Broken down by operation type.",
		},
		[]string{"operation_type"},
	)
	RuntimeOperationsErrors = prometheus.NewCounterVec(
		prometheus.CounterOpts{
			Subsystem: KubeletSubsystem,
			Name:      RuntimeOperationsErrorsKey,
			Help:      "Cumulative number of runtime operation errors by operation type.",
		},
		[]string{"operation_type"},
	)
	EvictionStatsAge = prometheus.NewSummaryVec(
		prometheus.SummaryOpts{
			Subsystem: KubeletSubsystem,
			Name:      EvictionStatsAgeKey,
			Help:      "Time between when stats are collected, and when pod is evicted based on those stats by eviction signal",
		},
		[]string{"eviction_signal"},
	)
	DevicePluginRegistrationCount = prometheus.NewCounterVec(
		prometheus.CounterOpts{
			Subsystem: KubeletSubsystem,
			Name:      DevicePluginRegistrationCountKey,
			Help:      "Cumulative number of device plugin registrations. Broken down by resource name.",
		},
		[]string{"resource_name"},
	)
	DevicePluginAllocationLatency = prometheus.NewSummaryVec(
		prometheus.SummaryOpts{
			Subsystem: KubeletSubsystem,
			Name:      DevicePluginAllocationLatencyKey,
			Help:      "Latency in microseconds to serve a device plugin Allocation request. Broken down by resource name.",
		},
		[]string{"resource_name"},
	)
)