// clusterSyncLoop observes running clusters changes, and apply all services to new added cluster
// and add dns records for the changes
func (s *ServiceController) clusterSyncLoop() {
var servicesToUpdate []*cachedService
// should we remove cache for cluster from ready to not ready? should remove the condition predicate if no
clusters, err := s.clusterStore.ClusterCondition(getClusterConditionPredicate()).List()
if err != nil {
glog.Infof("Fail to get cluster list")
return
}
newClusters := clustersFromList(&clusters)
var newSet, increase sets.String
newSet = sets.NewString(newClusters...)
if newSet.Equal(s.knownClusterSet) {
// The set of cluster names in the services in the federation hasn't changed, but we can retry
// updating any services that we failed to update last time around.
servicesToUpdate = s.updateDNSRecords(servicesToUpdate, newClusters)
return
}
glog.Infof("Detected change in list of cluster names. New set: %v, Old set: %v", newSet, s.knownClusterSet)
increase = newSet.Difference(s.knownClusterSet)
// do nothing when cluster is removed.
if increase != nil {
// Try updating all services, and save the ones that fail to try again next
// round.
servicesToUpdate = s.serviceCache.allServices()
numServices := len(servicesToUpdate)
for newCluster := range increase {
glog.Infof("New cluster observed %s", newCluster)
s.updateAllServicesToCluster(servicesToUpdate, newCluster)
}
servicesToUpdate = s.updateDNSRecords(servicesToUpdate, newClusters)
glog.Infof("Successfully updated %d out of %d DNS records to direct traffic to the updated cluster",
numServices-len(servicesToUpdate), numServices)
}
s.knownClusterSet = newSet
}