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			260 lines
		
	
	
		
			8.8 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
| /*
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| Copyright 2017 The Kubernetes Authors.
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| 
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| Licensed under the Apache License, Version 2.0 (the "License");
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| you may not use this file except in compliance with the License.
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| You may obtain a copy of the License at
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| 
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|     http://www.apache.org/licenses/LICENSE-2.0
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| 
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| Unless required by applicable law or agreed to in writing, software
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| distributed under the License is distributed on an "AS IS" BASIS,
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| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| See the License for the specific language governing permissions and
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| limitations under the License.
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| */
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| 
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| // Package reconcilers master count based reconciler
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| package reconcilers
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| 
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| import (
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| 	"net"
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| 	"sync"
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| 
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| 	corev1 "k8s.io/api/core/v1"
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| 	"k8s.io/apimachinery/pkg/api/errors"
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| 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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| 	"k8s.io/client-go/util/retry"
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| 	"k8s.io/klog/v2"
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| 	endpointsv1 "k8s.io/kubernetes/pkg/api/v1/endpoints"
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| )
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| 
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| // masterCountEndpointReconciler reconciles endpoints based on a specified expected number of
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| // masters. masterCountEndpointReconciler implements EndpointReconciler.
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| type masterCountEndpointReconciler struct {
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| 	masterCount           int
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| 	epAdapter             EndpointsAdapter
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| 	stopReconcilingCalled bool
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| 	reconcilingLock       sync.Mutex
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| }
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| 
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| // NewMasterCountEndpointReconciler creates a new EndpointReconciler that reconciles based on a
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| // specified expected number of masters.
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| func NewMasterCountEndpointReconciler(masterCount int, epAdapter EndpointsAdapter) EndpointReconciler {
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| 	return &masterCountEndpointReconciler{
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| 		masterCount: masterCount,
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| 		epAdapter:   epAdapter,
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| 	}
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| }
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| 
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| // ReconcileEndpoints sets the endpoints for the given apiserver service (ro or rw).
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| // ReconcileEndpoints expects that the endpoints objects it manages will all be
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| // managed only by ReconcileEndpoints; therefore, to understand this, you need only
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| // understand the requirements and the body of this function.
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| //
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| // Requirements:
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| //  * All apiservers MUST use the same ports for their {rw, ro} services.
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| //  * All apiservers MUST use ReconcileEndpoints and only ReconcileEndpoints to manage the
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| //      endpoints for their {rw, ro} services.
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| //  * All apiservers MUST know and agree on the number of apiservers expected
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| //      to be running (c.masterCount).
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| //  * ReconcileEndpoints is called periodically from all apiservers.
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| func (r *masterCountEndpointReconciler) ReconcileEndpoints(serviceName string, ip net.IP, endpointPorts []corev1.EndpointPort, reconcilePorts bool) error {
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| 	r.reconcilingLock.Lock()
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| 	defer r.reconcilingLock.Unlock()
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| 
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| 	if r.stopReconcilingCalled {
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| 		return nil
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| 	}
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| 
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| 	e, err := r.epAdapter.Get(metav1.NamespaceDefault, serviceName, metav1.GetOptions{})
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| 	if err != nil {
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| 		e = &corev1.Endpoints{
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| 			ObjectMeta: metav1.ObjectMeta{
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| 				Name:      serviceName,
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| 				Namespace: metav1.NamespaceDefault,
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| 			},
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| 		}
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| 	}
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| 
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| 	// Don't use the EndpointSliceMirroring controller to mirror this to
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| 	// EndpointSlices. This may change in the future.
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| 	skipMirrorChanged := setSkipMirrorTrue(e)
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| 
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| 	if errors.IsNotFound(err) {
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| 		// Simply create non-existing endpoints for the service.
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| 		e.Subsets = []corev1.EndpointSubset{{
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| 			Addresses: []corev1.EndpointAddress{{IP: ip.String()}},
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| 			Ports:     endpointPorts,
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| 		}}
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| 		_, err = r.epAdapter.Create(metav1.NamespaceDefault, e)
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| 		return err
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| 	}
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| 
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| 	// First, determine if the endpoint is in the format we expect (one
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| 	// subset, ports matching endpointPorts, N IP addresses).
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| 	formatCorrect, ipCorrect, portsCorrect := checkEndpointSubsetFormat(e, ip.String(), endpointPorts, r.masterCount, reconcilePorts)
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| 	if !formatCorrect {
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| 		// Something is egregiously wrong, just re-make the endpoints record.
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| 		e.Subsets = []corev1.EndpointSubset{{
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| 			Addresses: []corev1.EndpointAddress{{IP: ip.String()}},
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| 			Ports:     endpointPorts,
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| 		}}
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| 		klog.Warningf("Resetting endpoints for master service %q to %#v", serviceName, e)
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| 		_, err = r.epAdapter.Update(metav1.NamespaceDefault, e)
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| 		return err
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| 	}
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| 
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| 	if !skipMirrorChanged && ipCorrect && portsCorrect {
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| 		return r.epAdapter.EnsureEndpointSliceFromEndpoints(metav1.NamespaceDefault, e)
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| 	}
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| 	if !ipCorrect {
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| 		// We *always* add our own IP address.
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| 		e.Subsets[0].Addresses = append(e.Subsets[0].Addresses, corev1.EndpointAddress{IP: ip.String()})
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| 
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| 		// Lexicographic order is retained by this step.
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| 		e.Subsets = endpointsv1.RepackSubsets(e.Subsets)
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| 
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| 		// If too many IP addresses, remove the ones lexicographically after our
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| 		// own IP address.  Given the requirements stated at the top of
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| 		// this function, this should cause the list of IP addresses to
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| 		// become eventually correct.
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| 		if addrs := &e.Subsets[0].Addresses; len(*addrs) > r.masterCount {
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| 			// addrs is a pointer because we're going to mutate it.
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| 			for i, addr := range *addrs {
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| 				if addr.IP == ip.String() {
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| 					for len(*addrs) > r.masterCount {
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| 						// wrap around if necessary.
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| 						remove := (i + 1) % len(*addrs)
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| 						*addrs = append((*addrs)[:remove], (*addrs)[remove+1:]...)
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| 					}
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| 					break
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| 				}
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| 			}
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| 		}
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| 	}
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| 	if !portsCorrect {
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| 		// Reset ports.
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| 		e.Subsets[0].Ports = endpointPorts
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| 	}
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| 	klog.Warningf("Resetting endpoints for master service %q to %v", serviceName, e)
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| 	_, err = r.epAdapter.Update(metav1.NamespaceDefault, e)
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| 	return err
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| }
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| 
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| func (r *masterCountEndpointReconciler) RemoveEndpoints(serviceName string, ip net.IP, endpointPorts []corev1.EndpointPort) error {
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| 	r.reconcilingLock.Lock()
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| 	defer r.reconcilingLock.Unlock()
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| 
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| 	e, err := r.epAdapter.Get(metav1.NamespaceDefault, serviceName, metav1.GetOptions{})
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| 	if err != nil {
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| 		if errors.IsNotFound(err) {
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| 			// Endpoint doesn't exist
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| 			return nil
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| 		}
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| 		return err
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| 	}
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| 
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| 	if len(e.Subsets) == 0 {
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| 		// no action is needed to remove the endpoint
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| 		return nil
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| 	}
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| 	// Remove our IP from the list of addresses
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| 	new := []corev1.EndpointAddress{}
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| 	for _, addr := range e.Subsets[0].Addresses {
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| 		if addr.IP != ip.String() {
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| 			new = append(new, addr)
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| 		}
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| 	}
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| 	e.Subsets[0].Addresses = new
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| 	e.Subsets = endpointsv1.RepackSubsets(e.Subsets)
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| 	err = retry.RetryOnConflict(retry.DefaultBackoff, func() error {
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| 		_, err := r.epAdapter.Update(metav1.NamespaceDefault, e)
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| 		return err
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| 	})
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| 	return err
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| }
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| 
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| func (r *masterCountEndpointReconciler) StopReconciling() {
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| 	r.reconcilingLock.Lock()
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| 	defer r.reconcilingLock.Unlock()
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| 	r.stopReconcilingCalled = true
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| }
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| 
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| // Determine if the endpoint is in the format ReconcileEndpoints expects.
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| //
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| // Return values:
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| // * formatCorrect is true if exactly one subset is found.
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| // * ipCorrect is true when current master's IP is found and the number
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| //     of addresses is less than or equal to the master count.
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| // * portsCorrect is true when endpoint ports exactly match provided ports.
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| //     portsCorrect is only evaluated when reconcilePorts is set to true.
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| func checkEndpointSubsetFormat(e *corev1.Endpoints, ip string, ports []corev1.EndpointPort, count int, reconcilePorts bool) (formatCorrect bool, ipCorrect bool, portsCorrect bool) {
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| 	if len(e.Subsets) != 1 {
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| 		return false, false, false
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| 	}
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| 	sub := &e.Subsets[0]
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| 	portsCorrect = true
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| 	if reconcilePorts {
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| 		if len(sub.Ports) != len(ports) {
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| 			portsCorrect = false
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| 		}
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| 		for i, port := range ports {
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| 			if len(sub.Ports) <= i || port != sub.Ports[i] {
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| 				portsCorrect = false
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| 				break
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| 			}
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| 		}
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| 	}
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| 	for _, addr := range sub.Addresses {
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| 		if addr.IP == ip {
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| 			ipCorrect = len(sub.Addresses) <= count
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| 			break
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| 		}
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| 	}
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| 	return true, ipCorrect, portsCorrect
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| }
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| 
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| // GetMasterServiceUpdateIfNeeded sets service attributes for the
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| //     given apiserver service.
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| // * GetMasterServiceUpdateIfNeeded expects that the service object it
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| //     manages will be managed only by GetMasterServiceUpdateIfNeeded;
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| //     therefore, to understand this, you need only understand the
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| //     requirements and the body of this function.
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| // * GetMasterServiceUpdateIfNeeded ensures that the correct ports are
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| //     are set.
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| //
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| // Requirements:
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| // * All apiservers MUST use GetMasterServiceUpdateIfNeeded and only
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| //     GetMasterServiceUpdateIfNeeded to manage service attributes
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| // * updateMasterService is called periodically from all apiservers.
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| func GetMasterServiceUpdateIfNeeded(svc *corev1.Service, servicePorts []corev1.ServicePort, serviceType corev1.ServiceType) (s *corev1.Service, updated bool) {
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| 	// Determine if the service is in the format we expect
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| 	// (servicePorts are present and service type matches)
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| 	formatCorrect := checkServiceFormat(svc, servicePorts, serviceType)
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| 	if formatCorrect {
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| 		return svc, false
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| 	}
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| 	svc.Spec.Ports = servicePorts
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| 	svc.Spec.Type = serviceType
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| 	return svc, true
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| }
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| 
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| // Determine if the service is in the correct format
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| // GetMasterServiceUpdateIfNeeded expects (servicePorts are correct
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| // and service type matches).
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| func checkServiceFormat(s *corev1.Service, ports []corev1.ServicePort, serviceType corev1.ServiceType) (formatCorrect bool) {
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| 	if s.Spec.Type != serviceType {
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| 		return false
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| 	}
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| 	if len(ports) != len(s.Spec.Ports) {
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| 		return false
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| 	}
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| 	for i, port := range ports {
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| 		if port != s.Spec.Ports[i] {
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| 			return false
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| 		}
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| 	}
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| 	return true
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| }
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