TrueCloudLab/coredns
16
0
Fork 2
Code Issues Pull requests 1 Projects Releases Packages Wiki Activity Actions

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

Browse source 
* 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
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
3 changed files with 106 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

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
}
}
}