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plugin/kubernetes: Support both v1 and v1beta1 EndpointSlices (#4570)

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* support v1 and v1beta1 endpointslice

Signed-off-by: Chris O'Haver <cohaver@infoblox.com>

* update comments

Signed-off-by: Chris O'Haver <cohaver@infoblox.com>
This commit is contained in:
Chris O'Haver 2021-05-10 12:57:23 -04:00 • committed by GitHub
parent 7354552296
commit 24547447d0
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 106 additions and 12 deletions
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41
plugin/kubernetes/controller.go
View file

@ -11,7 +11,8 @@ import (
"github.com/coredns/coredns/plugin/kubernetes/object"
api "k8s.io/api/core/v1"
discovery "k8s.io/api/discovery/v1beta1"
discovery "k8s.io/api/discovery/v1"
discoveryV1beta1 "k8s.io/api/discovery/v1beta1"
meta "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/runtime"
@ -180,6 +181,23 @@ func (dns *dnsControl) WatchEndpoints(ctx context.Context) {
dns.epLock.Unlock()
}
// WatchEndpointSliceV1beta1 will set the endpoint Lister and Controller to watch v1beta1
// instead of the default v1.
func (dns *dnsControl) WatchEndpointSliceV1beta1(ctx context.Context) {
dns.epLock.Lock()
dns.epLister, dns.epController = object.NewIndexerInformer(
&cache.ListWatch{
ListFunc: endpointSliceListFuncV1beta1(ctx, dns.client, api.NamespaceAll, dns.selector),
WatchFunc: endpointSliceWatchFuncV1beta1(ctx, dns.client, api.NamespaceAll, dns.selector),
},
&discoveryV1beta1.EndpointSlice{},
cache.ResourceEventHandlerFuncs{AddFunc: dns.Add, UpdateFunc: dns.Update, DeleteFunc: dns.Delete},
cache.Indexers{epNameNamespaceIndex: epNameNamespaceIndexFunc, epIPIndex: epIPIndexFunc},
object.DefaultProcessor(object.EndpointSliceV1beta1ToEndpoints, dns.EndpointSliceLatencyRecorder()),
)
dns.epLock.Unlock()
}
func (dns *dnsControl) EndpointsLatencyRecorder() *object.EndpointLatencyRecorder {
return &object.EndpointLatencyRecorder{
ServiceFunc: func(o meta.Object) []*object.Service {
@ -262,13 +280,21 @@ func podListFunc(ctx context.Context, c kubernetes.Interface, ns string, s label
return c.CoreV1().Pods(ns).List(ctx, opts)
}
}
func endpointSliceListFuncV1beta1(ctx context.Context, c kubernetes.Interface, ns string, s labels.Selector) func(meta.ListOptions) (runtime.Object, error) {
return func(opts meta.ListOptions) (runtime.Object, error) {
if s != nil {
opts.LabelSelector = s.String()
}
return c.DiscoveryV1beta1().EndpointSlices(ns).List(ctx, opts)
}
}
func endpointSliceListFunc(ctx context.Context, c kubernetes.Interface, ns string, s labels.Selector) func(meta.ListOptions) (runtime.Object, error) {
return func(opts meta.ListOptions) (runtime.Object, error) {
if s != nil {
opts.LabelSelector = s.String()
}
return c.DiscoveryV1beta1().EndpointSlices(ns).List(ctx, opts)
return c.DiscoveryV1().EndpointSlices(ns).List(ctx, opts)
}
}
@ -312,7 +338,7 @@ func podWatchFunc(ctx context.Context, c kubernetes.Interface, ns string, s labe
}
}
func endpointSliceWatchFunc(ctx context.Context, c kubernetes.Interface, ns string, s labels.Selector) func(options meta.ListOptions) (watch.Interface, error) {
func endpointSliceWatchFuncV1beta1(ctx context.Context, c kubernetes.Interface, ns string, s labels.Selector) func(options meta.ListOptions) (watch.Interface, error) {
return func(options meta.ListOptions) (watch.Interface, error) {
if s != nil {
options.LabelSelector = s.String()
@ -321,6 +347,15 @@ func endpointSliceWatchFunc(ctx context.Context, c kubernetes.Interface, ns stri
}
}
func endpointSliceWatchFunc(ctx context.Context, c kubernetes.Interface, ns string, s labels.Selector) func(options meta.ListOptions) (watch.Interface, error) {
return func(options meta.ListOptions) (watch.Interface, error) {
if s != nil {
options.LabelSelector = s.String()
}
return c.DiscoveryV1().EndpointSlices(ns).Watch(ctx, options)
}
}
func endpointsWatchFunc(ctx context.Context, c kubernetes.Interface, ns string, s labels.Selector) func(options meta.ListOptions) (watch.Interface, error) {
return func(options meta.ListOptions) (watch.Interface, error) {
if s != nil {

29
plugin/kubernetes/kubernetes.go
View file

@ -20,7 +20,8 @@ import (
"github.com/miekg/dns"
api "k8s.io/api/core/v1"
discovery "k8s.io/api/discovery/v1beta1"
discovery "k8s.io/api/discovery/v1"
discoveryV1beta1 "k8s.io/api/discovery/v1beta1"
meta "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/client-go/kubernetes"
@ -256,10 +257,15 @@ func (k *Kubernetes) InitKubeCache(ctx context.Context) (onStart func() error, o
go func() {
if initEndpointWatch {
// Revert to watching Endpoints for incompatible K8s.
// This can be remove when all supported k8s versions support endpointslices.
if ok := k.endpointSliceSupported(kubeClient); !ok {
// This can be removed when all supported k8s versions support endpointslices.
ok, v := k.endpointSliceSupported(kubeClient)
if !ok {
k.APIConn.(*dnsControl).WatchEndpoints(ctx)
}
// Revert to EndpointSlice v1beta1 if v1 is not supported
if ok && v == discoveryV1beta1.SchemeGroupVersion.String() {
k.APIConn.(*dnsControl).WatchEndpointSliceV1beta1(ctx)
}
}
k.APIConn.Run()
}()
@ -290,9 +296,12 @@ func (k *Kubernetes) InitKubeCache(ctx context.Context) (onStart func() error, o
// endpointSliceSupported will determine which endpoint object type to watch (endpointslices or endpoints)
// based on the supportability of endpointslices in the API and server version. It will return true when endpointslices
// should be watched, and false when endpoints should be watched.
// If the API supports discovery v1 beta1, and the server versions >= 1.19, endpointslices are watched.
// This function should be removed, along with non-slice endpoint watch code, when support for k8s < 1.19 is dropped.
func (k *Kubernetes) endpointSliceSupported(kubeClient *kubernetes.Clientset) bool {
// If the API supports discovery, and the server versions >= 1.19, true is returned.
// Also returned is the discovery version supported: "v1" if v1 is supported, and v1beta1 if v1beta1 is supported and
// v1 is not supported.
// This function should be removed, when all supported versions of k8s support v1.
func (k *Kubernetes) endpointSliceSupported(kubeClient *kubernetes.Clientset) (bool, string) {
var sliceVer string
useEndpointSlices := false
ticker := time.NewTicker(100 * time.Millisecond)
defer ticker.Stop()
@ -303,9 +312,13 @@ func (k *Kubernetes) endpointSliceSupported(kubeClient *kubernetes.Clientset) bo
if err != nil {
continue
}
// Enable use of endpoint slices if the API supports the discovery v1 beta1 api
// Enable use of endpoint slices if the API supports the discovery api
if _, err := kubeClient.Discovery().ServerResourcesForGroupVersion(discovery.SchemeGroupVersion.String()); err == nil {
useEndpointSlices = true
sliceVer = discovery.SchemeGroupVersion.String()
} else if _, err := kubeClient.Discovery().ServerResourcesForGroupVersion(discoveryV1beta1.SchemeGroupVersion.String()); err == nil {
useEndpointSlices = true
sliceVer = discoveryV1beta1.SchemeGroupVersion.String()
}
// Disable use of endpoint slices for k8s versions 1.18 and earlier. The Endpointslices API was enabled
// by default in 1.17 but Service -> Pod proxy continued to use Endpoints by default until 1.19.
@ -317,7 +330,7 @@ func (k *Kubernetes) endpointSliceSupported(kubeClient *kubernetes.Clientset) bo
log.Info("Watching Endpoints instead of EndpointSlices in k8s versions < 1.19")
useEndpointSlices = false
}
return useEndpointSlices
return useEndpointSlices, sliceVer
}
}
}

48
plugin/kubernetes/object/endpoint.go
View file

@ -4,7 +4,8 @@ import (
"fmt"
api "k8s.io/api/core/v1"
discovery "k8s.io/api/discovery/v1beta1"
discovery "k8s.io/api/discovery/v1"
discoveryV1beta1 "k8s.io/api/discovery/v1beta1"
meta "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
)
@ -151,6 +152,51 @@ func EndpointSliceToEndpoints(obj meta.Object) (meta.Object, error) {
return e, nil
}
// EndpointSliceV1beta1ToEndpoints converts a v1beta1 *discovery.EndpointSlice to a *Endpoints.
func EndpointSliceV1beta1ToEndpoints(obj meta.Object) (meta.Object, error) {
ends, ok := obj.(*discoveryV1beta1.EndpointSlice)
if !ok {
return nil, fmt.Errorf("unexpected object %v", obj)
}
e := &Endpoints{
Version: ends.GetResourceVersion(),
Name: ends.GetName(),
Namespace: ends.GetNamespace(),
Index: EndpointsKey(ends.Labels[discovery.LabelServiceName], ends.GetNamespace()),
Subsets: make([]EndpointSubset, 1),
}
if len(ends.Ports) == 0 {
// Add sentinel if there are no ports.
e.Subsets[0].Ports = []EndpointPort{{Port: -1}}
} else {
e.Subsets[0].Ports = make([]EndpointPort, len(ends.Ports))
for k, p := range ends.Ports {
ep := EndpointPort{Port: *p.Port, Name: *p.Name, Protocol: string(*p.Protocol)}
e.Subsets[0].Ports[k] = ep
}
}
for _, end := range ends.Endpoints {
for _, a := range end.Addresses {
ea := EndpointAddress{IP: a}
if end.Hostname != nil {
ea.Hostname = *end.Hostname
}
if end.TargetRef != nil {
ea.TargetRefName = end.TargetRef.Name
}
// EndpointSlice does not contain NodeName, leave blank
e.Subsets[0].Addresses = append(e.Subsets[0].Addresses, ea)
e.IndexIP = append(e.IndexIP, a)
}
}
*ends = discoveryV1beta1.EndpointSlice{}
return e, nil
}
// CopyWithoutSubsets copies e, without the subsets.
func (e *Endpoints) CopyWithoutSubsets() *Endpoints {
e1 := &Endpoints{