const (
    // DockerOperationsKey is the key for docker operation metrics.
    DockerOperationsKey = "docker_operations_total"
    // DockerOperationsLatencyKey is the key for the operation latency metrics.
    DockerOperationsLatencyKey = "docker_operations_duration_seconds"
    // DockerOperationsErrorsKey is the key for the operation error metrics.
    DockerOperationsErrorsKey = "docker_operations_errors_total"
    // DockerOperationsTimeoutKey is the key for the operation timeout metrics.
    DockerOperationsTimeoutKey = "docker_operations_timeout_total"

    // DeprecatedDockerOperationsKey is the deprecated key for docker operation metrics.
    DeprecatedDockerOperationsKey = "docker_operations"
    // DeprecatedDockerOperationsLatencyKey is the deprecated key for the operation latency metrics.
    DeprecatedDockerOperationsLatencyKey = "docker_operations_latency_microseconds"
    // DeprecatedDockerOperationsErrorsKey is the deprecated key for the operation error metrics.
    DeprecatedDockerOperationsErrorsKey = "docker_operations_errors"
    // DeprecatedDockerOperationsTimeoutKey is the deprecated key for the operation timeout metrics.
    DeprecatedDockerOperationsTimeoutKey = "docker_operations_timeout"
)

var (
    // DockerOperationsLatency collects operation latency numbers by operation
    // type.
    DockerOperationsLatency = prometheus.NewHistogramVec(
        prometheus.HistogramOpts{
            Subsystem: kubeletSubsystem,
            Name:      DockerOperationsLatencyKey,
            Help:      "Latency in seconds of Docker operations. Broken down by operation type.",
            Buckets:   prometheus.DefBuckets,
        },
        []string{"operation_type"},
    )
    // DockerOperations collects operation counts by operation type.
    DockerOperations = prometheus.NewCounterVec(
        prometheus.CounterOpts{
            Subsystem: kubeletSubsystem,
            Name:      DockerOperationsKey,
            Help:      "Cumulative number of Docker operations by operation type.",
        },
        []string{"operation_type"},
    )
    // DockerOperationsErrors collects operation errors by operation
    // type.
    DockerOperationsErrors = prometheus.NewCounterVec(
        prometheus.CounterOpts{
            Subsystem: kubeletSubsystem,
            Name:      DockerOperationsErrorsKey,
            Help:      "Cumulative number of Docker operation errors by operation type.",
        },
        []string{"operation_type"},
    )
    // DockerOperationsTimeout collects operation timeouts by operation type.
    DockerOperationsTimeout = prometheus.NewCounterVec(
        prometheus.CounterOpts{
            Subsystem: kubeletSubsystem,
            Name:      DockerOperationsTimeoutKey,
            Help:      "Cumulative number of Docker operation timeout by operation type.",
        },
        []string{"operation_type"},
    )

    // DeprecatedDockerOperationsLatency collects operation latency numbers by operation
    // type.
    DeprecatedDockerOperationsLatency = prometheus.NewSummaryVec(
        prometheus.SummaryOpts{
            Subsystem: kubeletSubsystem,
            Name:      DeprecatedDockerOperationsLatencyKey,
            Help:      "(Deprecated) Latency in microseconds of Docker operations. Broken down by operation type.",
        },
        []string{"operation_type"},
    )
    // DeprecatedDockerOperations collects operation counts by operation type.
    DeprecatedDockerOperations = prometheus.NewCounterVec(
        prometheus.CounterOpts{
            Subsystem: kubeletSubsystem,
            Name:      DeprecatedDockerOperationsKey,
            Help:      "(Deprecated) Cumulative number of Docker operations by operation type.",
        },
        []string{"operation_type"},
    )
    // DeprecatedDockerOperationsErrors collects operation errors by operation
    // type.
    DeprecatedDockerOperationsErrors = prometheus.NewCounterVec(
        prometheus.CounterOpts{
            Subsystem: kubeletSubsystem,
            Name:      DeprecatedDockerOperationsErrorsKey,
            Help:      "(Deprecated) Cumulative number of Docker operation errors by operation type.",
        },
        []string{"operation_type"},
    )
    // DeprecatedDockerOperationsTimeout collects operation timeouts by operation type.
    DeprecatedDockerOperationsTimeout = prometheus.NewCounterVec(
        prometheus.CounterOpts{
            Subsystem: kubeletSubsystem,
            Name:      DeprecatedDockerOperationsTimeoutKey,
            Help:      "(Deprecated) Cumulative number of Docker operation timeout by operation type.",
        },
        []string{"operation_type"},
    )
)