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plugin/kubernetes: consistently choose EndpointSlices or Endpoints for unstable API (#4647)

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* confirm endpointslices is served or not

Signed-off-by: uesyn <suemura@zlab.co.jp>

* Apply suggestions

Signed-off-by: uesyn <suemura@zlab.co.jp>
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uesyn 2021-05-27 21:48:52 +09:00 • committed by GitHub
parent d8a0d97df2
commit 4c0fdc3909
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1 changed files with 23 additions and 13 deletions
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36
plugin/kubernetes/kubernetes.go
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@ -22,6 +22,7 @@ import (
api "k8s.io/api/core/v1"
discovery "k8s.io/api/discovery/v1"
discoveryV1beta1 "k8s.io/api/discovery/v1beta1"
kerrors "k8s.io/apimachinery/pkg/api/errors"
meta "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/client-go/kubernetes"
@ -301,8 +302,6 @@ func (k *Kubernetes) InitKubeCache(ctx context.Context) (onStart func() error, o
// 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()
for {
@ -312,25 +311,36 @@ func (k *Kubernetes) endpointSliceSupported(kubeClient *kubernetes.Clientset) (b
if err != nil {
continue
}
// 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.
// DNS results should be built from the same source data that the proxy uses. This decision assumes
// k8s EndpointSliceProxying featuregate is at the default (i.e. only enabled for k8s >= 1.19).
major, _ := strconv.Atoi(sv.Major)
minor, _ := strconv.Atoi(strings.TrimRight(sv.Minor, "+"))
if useEndpointSlices && major <= 1 && minor <= 18 {
if major <= 1 && minor <= 18 {
log.Info("Watching Endpoints instead of EndpointSlices in k8s versions < 1.19")
useEndpointSlices = false
return false, ""
}
return useEndpointSlices, sliceVer
// Enable use of endpoint slices if the API supports the discovery api
_, err = kubeClient.Discovery().ServerResourcesForGroupVersion(discovery.SchemeGroupVersion.String())
if err == nil {
return true, discovery.SchemeGroupVersion.String()
} else if !kerrors.IsNotFound(err) {
continue
}
_, err = kubeClient.Discovery().ServerResourcesForGroupVersion(discoveryV1beta1.SchemeGroupVersion.String())
if err == nil {
return true, discoveryV1beta1.SchemeGroupVersion.String()
} else if !kerrors.IsNotFound(err) {
continue
}
// Disable use of endpoint slices in case that it is disabled in k8s versions 1.19 and newer.
log.Info("Endpointslices API disabled. Watching Endpoints instead.")
return false, ""
}
}
}