How many historical versions does Squad keep?
Squad.Spec.RevisionHistoryLimit controls the number of historical versions of Squad, and the default is 10.
When Squad scaling-up, is the replicas created serially or concurrently?
Squad controls the number of copies of GameServer through GameServerSet. When adding copies, multiple (16) Goroutines concurrently create GameServer:
func (c *Controller) addMoreGameServers(gsSet *carrierv1alpha1.GameServerSet, count int) error {
klog.Infof("Adding more gameservers: %v, count: %v", gsSet.Name, count)
return parallelize(newGameServersChannel(count, gsSet), maxCreationParalellism, func(gs *carrierv1alpha1.GameServer) error {
gameservers.ApplyDefaults(gs)
gs, err := c.gameServerGetter.GameServers(gs.Namespace).Create(gs)
if err != nil {
return errors.Wrapf(err, "error creating gameserver for gameserverset %s", gsSet.Name)
}
c.stateCache.forGameServerSet(gsSet).created(gs)
c.recorder.Eventf(gsSet, corev1.EventTypeNormal, "SuccessfulCreate", "Created gameserver: %s", gs.Name)
return nil
})
}
Check DeleteableGates when Squad is updated
When Squad is scaling-down and deleting GameServer, it will check the DeleteableGates condition. Only when all the DeleteableGates condition will be True (controlled by the application), will the corresponding GameServer be deleted:
// IsDeletable returns false if the server is currently not deletable
func IsDeletable(gs *carrierv1alpha1.GameServer) bool {
if IsBeforeReady(gs) {
return true
}
condMap := make(map[string]carrierv1alpha1.ConditionStatus, len(gs.Status.Conditions))
for _, condition := range gs.Status.Conditions {
condMap[string(condition.Type)] = condition.Status
}
for _, gate := range gs.Spec.DeletableGates {
if v, ok := condMap[gate]; !ok || v != carrierv1alpha1.ConditionTrue {
return false
}
}
return true
}
Similarly, Squad supports graceful updates. When Squad updates and deletes GameServer, it will also check the DeleteableGates condition.