package object
import (
"time"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/pkg/log"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promauto"
api "k8s.io/api/core/v1"
meta "k8s.io/apimachinery/pkg/apis/meta/v1"
)
var (
// DNSProgrammingLatency is defined as the time it took to program a DNS instance - from the time
// a service or pod has changed to the time the change was propagated and was available to be
// served by a DNS server.
// The definition of this SLI can be found at https://github.com/kubernetes/community/blob/master/sig-scalability/slos/dns_programming_latency.md
// Note that the metrics is partially based on the time exported by the endpoints controller on
// the master machine. The measurement may be inaccurate if there is a clock drift between the
// node and master machine.
// The service_kind label can be one of:
// * cluster_ip
// * headless_with_selector
// * headless_without_selector
DNSProgrammingLatency = promauto.NewHistogramVec(prometheus.HistogramOpts{
Namespace: plugin.Namespace,
Subsystem: "kubernetes",
Name: "dns_programming_duration_seconds",
// From 1 millisecond to ~17 minutes.
Buckets: prometheus.ExponentialBuckets(0.001, 2, 20),
Help: "Histogram of the time (in seconds) it took to program a dns instance.",
}, []string{"service_kind"})
// DurationSinceFunc returns the duration elapsed since the given time.
// Added as a global variable to allow injection for testing.
DurationSinceFunc = time.Since
)
// EndpointLatencyRecorder records latency metric for endpoint objects
type EndpointLatencyRecorder struct {
TT time.Time
ServiceFunc func(meta.Object) []*Service
Services []*Service
}
func (l *EndpointLatencyRecorder) init(o meta.Object) {
l.Services = l.ServiceFunc(o)
l.TT = time.Time{}
stringVal, ok := o.GetAnnotations()[api.EndpointsLastChangeTriggerTime]
if ok {
tt, err := time.Parse(time.RFC3339Nano, stringVal)
if err != nil {
log.Warningf("DnsProgrammingLatency cannot be calculated for Endpoints '%s/%s'; invalid %q annotation RFC3339 value of %q",
o.GetNamespace(), o.GetName(), api.EndpointsLastChangeTriggerTime, stringVal)
// In case of error val = time.Zero, which is ignored downstream.
}
l.TT = tt
}
}
func (l *EndpointLatencyRecorder) record() {
// isHeadless indicates whether the endpoints object belongs to a headless
// service (i.e. clusterIp = None). Note that this can be a false negatives if the service
// informer is lagging, i.e. we may not see a recently created service. Given that the services
// don't change very often (comparing to much more frequent endpoints changes), cases when this method
// will return wrong answer should be relatively rare. Because of that we intentionally accept this
// flaw to keep the solution simple.
isHeadless := len(l.Services) == 1 && l.Services[0].Headless()
if !isHeadless || l.TT.IsZero() {
return
}
// If we're here it means that the Endpoints object is for a headless service and that
// the Endpoints object was created by the endpoints-controller (because the
// LastChangeTriggerTime annotation is set). It means that the corresponding service is a
// "headless service with selector".
DNSProgrammingLatency.WithLabelValues("headless_with_selector").
Observe(DurationSinceFunc(l.TT).Seconds())
}
ption value='derrick/test/add-ed25519-tests'>derrick/test/add-ed25519-tests
Unnamed repository; edit this file 'description' to name the repository.
Jarred Sumner