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plugin/kubernetes: Remove Endpoint and EndpointSlice v1beta Support (#6147)

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* remove endpoint and endpointslicev1beta watch support

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

* adjust readme

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

* informer object changes

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

* remove unused funcs

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

---------

Signed-off-by: Chris O'Haver <cohaver@infoblox.com>
This commit is contained in:
Chris O'Haver 2023-06-12 11:22:57 -04:00 • committed by GitHub
parent 6e6fc650ce
commit 06cd843918
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4 changed files with 1 additions and 276 deletions
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80
plugin/kubernetes/kubernetes.go
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@ -6,7 +6,6 @@ import (
"errors"
"fmt"
"net"
"strconv"
"strings"
"time"
@ -19,9 +18,6 @@ import (
"github.com/miekg/dns"
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"
@ -262,22 +258,8 @@ func (k *Kubernetes) InitKubeCache(ctx context.Context) (onStart func() error, o
k.APIConn = newdnsController(ctx, kubeClient, k.opts)
initEndpointWatch := k.opts.initEndpointsCache
onStart = func() error {
go func() {
if initEndpointWatch {
// Revert to watching Endpoints for incompatible K8s.
// 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()
}()
@ -311,68 +293,6 @@ func (k *Kubernetes) InitKubeCache(ctx context.Context) (onStart func() error, o
return onStart, onShut, err
}
// 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, 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) {
ticker := time.NewTicker(100 * time.Millisecond)
defer ticker.Stop()
logTicker := time.NewTicker(10 * time.Second)
defer logTicker.Stop()
var connErr error
for {
select {
case <-logTicker.C:
if connErr == nil {
continue
}
log.Warningf("Kubernetes API connection failure: %v", connErr)
case <-ticker.C:
sv, err := kubeClient.ServerVersion()
if err != nil {
connErr = err
continue
}
// 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 feature gate 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 major <= 1 && minor <= 18 {
log.Info("Watching Endpoints instead of EndpointSlices in k8s versions < 1.19")
return false, ""
}
// 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) {
connErr = err
continue
}
_, err = kubeClient.Discovery().ServerResourcesForGroupVersion(discoveryV1beta1.SchemeGroupVersion.String())
if err == nil {
return true, discoveryV1beta1.SchemeGroupVersion.String()
} else if !kerrors.IsNotFound(err) {
connErr = 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, ""
}
}
}
// Records looks up services in kubernetes.
func (k *Kubernetes) Records(ctx context.Context, state request.Request, exact bool) ([]msg.Service, error) {
r, e := parseRequest(state.Name(), state.Zone)