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controller.go
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controller.go
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// Copyright 2018 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package gameserversets
import (
"encoding/json"
"sort"
"sync"
"agones.dev/agones/pkg/apis/stable"
"agones.dev/agones/pkg/apis/stable/v1alpha1"
"agones.dev/agones/pkg/client/clientset/versioned"
getterv1alpha1 "agones.dev/agones/pkg/client/clientset/versioned/typed/stable/v1alpha1"
"agones.dev/agones/pkg/client/informers/externalversions"
listerv1alpha1 "agones.dev/agones/pkg/client/listers/stable/v1alpha1"
"agones.dev/agones/pkg/util/crd"
"agones.dev/agones/pkg/util/runtime"
"agones.dev/agones/pkg/util/webhooks"
"agones.dev/agones/pkg/util/workerqueue"
"github.com/heptiolabs/healthcheck"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
admv1beta1 "k8s.io/api/admission/v1beta1"
corev1 "k8s.io/api/core/v1"
extclientset "k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset"
"k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset/typed/apiextensions/v1beta1"
k8serrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/kubernetes/scheme"
typedcorev1 "k8s.io/client-go/kubernetes/typed/core/v1"
"k8s.io/client-go/tools/cache"
"k8s.io/client-go/tools/record"
)
var (
// ErrNoGameServerSetOwner is returned when a GameServerSet can't be found as an owner
// for a GameServer
ErrNoGameServerSetOwner = errors.New("No GameServerSet owner for this GameServer")
)
const (
maxCreationParalellism = 16
maxGameServerCreationsPerBatch = 64
maxDeletionParallelism = 64
maxGameServerDeletionsPerBatch = 64
// maxPodPendingCount is the maximum number of pending pods per game server set
maxPodPendingCount = 5000
)
// Controller is a the GameServerSet controller
type Controller struct {
logger *logrus.Entry
crdGetter v1beta1.CustomResourceDefinitionInterface
gameServerGetter getterv1alpha1.GameServersGetter
gameServerLister listerv1alpha1.GameServerLister
gameServerSynced cache.InformerSynced
gameServerSetGetter getterv1alpha1.GameServerSetsGetter
gameServerSetLister listerv1alpha1.GameServerSetLister
gameServerSetSynced cache.InformerSynced
workerqueue *workerqueue.WorkerQueue
stop <-chan struct{}
recorder record.EventRecorder
stateCache *gameServerStateCache
}
// NewController returns a new gameserverset crd controller
func NewController(
wh *webhooks.WebHook,
health healthcheck.Handler,
kubeClient kubernetes.Interface,
extClient extclientset.Interface,
agonesClient versioned.Interface,
agonesInformerFactory externalversions.SharedInformerFactory) *Controller {
gameServers := agonesInformerFactory.Stable().V1alpha1().GameServers()
gsInformer := gameServers.Informer()
gameServerSets := agonesInformerFactory.Stable().V1alpha1().GameServerSets()
gsSetInformer := gameServerSets.Informer()
c := &Controller{
crdGetter: extClient.ApiextensionsV1beta1().CustomResourceDefinitions(),
gameServerGetter: agonesClient.StableV1alpha1(),
gameServerLister: gameServers.Lister(),
gameServerSynced: gsInformer.HasSynced,
gameServerSetGetter: agonesClient.StableV1alpha1(),
gameServerSetLister: gameServerSets.Lister(),
gameServerSetSynced: gsSetInformer.HasSynced,
stateCache: &gameServerStateCache{},
}
c.logger = runtime.NewLoggerWithType(c)
c.workerqueue = workerqueue.NewWorkerQueue(c.syncGameServerSet, c.logger, stable.GroupName+".GameServerSetController")
health.AddLivenessCheck("gameserverset-workerqueue", healthcheck.Check(c.workerqueue.Healthy))
eventBroadcaster := record.NewBroadcaster()
eventBroadcaster.StartLogging(c.logger.Infof)
eventBroadcaster.StartRecordingToSink(&typedcorev1.EventSinkImpl{Interface: kubeClient.CoreV1().Events("")})
c.recorder = eventBroadcaster.NewRecorder(scheme.Scheme, corev1.EventSource{Component: "gameserverset-controller"})
wh.AddHandler("/validate", v1alpha1.Kind("GameServerSet"), admv1beta1.Update, c.updateValidationHandler)
gsSetInformer.AddEventHandler(cache.ResourceEventHandlerFuncs{
AddFunc: c.workerqueue.Enqueue,
UpdateFunc: func(oldObj, newObj interface{}) {
oldGss := oldObj.(*v1alpha1.GameServerSet)
newGss := newObj.(*v1alpha1.GameServerSet)
if oldGss.Spec.Replicas != newGss.Spec.Replicas {
c.workerqueue.Enqueue(newGss)
}
},
DeleteFunc: func(gsSet interface{}) {
c.stateCache.deleteGameServerSet(gsSet.(*v1alpha1.GameServerSet))
},
})
gsInformer.AddEventHandler(cache.ResourceEventHandlerFuncs{
AddFunc: c.gameServerEventHandler,
UpdateFunc: func(oldObj, newObj interface{}) {
gs := newObj.(*v1alpha1.GameServer)
// ignore if already being deleted
if gs.ObjectMeta.DeletionTimestamp == nil {
c.gameServerEventHandler(gs)
}
},
DeleteFunc: c.gameServerEventHandler,
})
return c
}
// Run the GameServerSet controller. Will block until stop is closed.
// Runs threadiness number workers to process the rate limited queue
func (c *Controller) Run(workers int, stop <-chan struct{}) error {
c.stop = stop
err := crd.WaitForEstablishedCRD(c.crdGetter, "gameserversets."+stable.GroupName, c.logger)
if err != nil {
return err
}
c.logger.Info("Wait for cache sync")
if !cache.WaitForCacheSync(stop, c.gameServerSynced, c.gameServerSetSynced) {
return errors.New("failed to wait for caches to sync")
}
c.workerqueue.Run(workers, stop)
return nil
}
// updateValidationHandler that validates a GameServerSet when is updated
// Should only be called on gameserverset update operations.
func (c *Controller) updateValidationHandler(review admv1beta1.AdmissionReview) (admv1beta1.AdmissionReview, error) {
c.logger.WithField("review", review).Info("updateValidationHandler")
newGss := &v1alpha1.GameServerSet{}
oldGss := &v1alpha1.GameServerSet{}
newObj := review.Request.Object
if err := json.Unmarshal(newObj.Raw, newGss); err != nil {
return review, errors.Wrapf(err, "error unmarshalling new GameServerSet json: %s", newObj.Raw)
}
oldObj := review.Request.OldObject
if err := json.Unmarshal(oldObj.Raw, oldGss); err != nil {
return review, errors.Wrapf(err, "error unmarshalling old GameServerSet json: %s", oldObj.Raw)
}
ok, causes := oldGss.ValidateUpdate(newGss)
if !ok {
review.Response.Allowed = false
details := metav1.StatusDetails{
Name: review.Request.Name,
Group: review.Request.Kind.Group,
Kind: review.Request.Kind.Kind,
Causes: causes,
}
review.Response.Result = &metav1.Status{
Status: metav1.StatusFailure,
Message: "GameServer update is invalid",
Reason: metav1.StatusReasonInvalid,
Details: &details,
}
c.logger.WithField("review", review).Info("Invalid GameServerSet update")
return review, nil
}
return review, nil
}
func (c *Controller) gameServerEventHandler(obj interface{}) {
gs, ok := obj.(*v1alpha1.GameServer)
if !ok {
return
}
ref := metav1.GetControllerOf(gs)
if ref == nil {
return
}
gsSet, err := c.gameServerSetLister.GameServerSets(gs.ObjectMeta.Namespace).Get(ref.Name)
if err != nil {
if k8serrors.IsNotFound(err) {
c.logger.WithField("ref", ref).Info("Owner GameServerSet no longer available for syncing")
} else {
runtime.HandleError(c.logger.WithField("gs", gs.ObjectMeta.Name).WithField("ref", ref),
errors.Wrap(err, "error retrieving GameServer owner"))
}
return
}
c.workerqueue.EnqueueImmediately(gsSet)
}
// syncGameServer synchronises the GameServers for the Set,
// making sure there are aways as many GameServers as requested
func (c *Controller) syncGameServerSet(key string) error {
c.logger.WithField("key", key).Info("syncGameServerSet")
defer c.logger.WithField("key", key).Info("syncGameServerSet finished")
// Convert the namespace/name string into a distinct namespace and name
namespace, name, err := cache.SplitMetaNamespaceKey(key)
if err != nil {
// don't return an error, as we don't want this retried
runtime.HandleError(c.logger.WithField("key", key), errors.Wrapf(err, "invalid resource key"))
return nil
}
gsSet, err := c.gameServerSetLister.GameServerSets(namespace).Get(name)
if err != nil {
if k8serrors.IsNotFound(err) {
c.logger.WithField("key", key).Info("GameServerSet is no longer available for syncing")
return nil
}
return errors.Wrapf(err, "error retrieving GameServerSet %s from namespace %s", name, namespace)
}
list, err := ListGameServersByGameServerSetOwner(c.gameServerLister, gsSet)
if err != nil {
return err
}
list = c.stateCache.forGameServerSet(gsSet).reconcileWithUpdatedServerList(list)
numServersToAdd, toDelete, isPartial := computeReconciliationAction(list, int(gsSet.Spec.Replicas), maxGameServerCreationsPerBatch, maxGameServerDeletionsPerBatch, maxPodPendingCount)
status := computeStatus(list)
fields := logrus.Fields{}
for _, gs := range list {
key := "gsCount" + string(gs.Status.State)
if gs.ObjectMeta.DeletionTimestamp != nil {
key = key + "Deleted"
}
v, ok := fields[key]
if !ok {
v = 0
}
fields[key] = v.(int) + 1
}
c.logger.
WithField("targetReplicaCount", gsSet.Spec.Replicas).
WithField("numServersToAdd", numServersToAdd).
WithField("numServersToDelete", len(toDelete)).
WithField("isPartial", isPartial).
WithField("status", status).
WithFields(fields).
Info("Reconciling GameServerSet")
if isPartial {
// we've determined that there's work to do, but we've decided not to do all the work in one shot
// make sure we get a follow-up, by re-scheduling this GSS in the worker queue immediately before this
// function returns
defer c.workerqueue.EnqueueImmediately(gsSet)
}
if numServersToAdd > 0 {
if err := c.addMoreGameServers(gsSet, numServersToAdd); err != nil {
c.logger.WithError(err).Warning("error adding game servers")
}
}
if len(toDelete) > 0 {
if err := c.deleteGameServers(gsSet, toDelete); err != nil {
c.logger.WithError(err).Warning("error deleting game servers")
}
}
return c.syncGameServerSetStatus(gsSet, list)
}
// computeReconciliationAction computes the action to take to reconcile a game server set set given
// the list of game servers that were found and target replica count.
func computeReconciliationAction(list []*v1alpha1.GameServer, targetReplicaCount int, maxCreations int, maxDeletions int, maxPending int) (int, []*v1alpha1.GameServer, bool) {
var upCount int // up == Ready or will become ready
// track the number of pods that are being created at any given moment by the GameServerSet
// so we can limit it at a throughput that Kubernetes can handle
var podPendingCount int // podPending == "up" but don't have a Pod running yet
var toDelete []*v1alpha1.GameServer
scheduleDeletion := func(gs *v1alpha1.GameServer) {
if gs.ObjectMeta.DeletionTimestamp.IsZero() {
toDelete = append(toDelete, gs)
}
}
handleGameServerUp := func(gs *v1alpha1.GameServer) {
if upCount >= targetReplicaCount {
scheduleDeletion(gs)
} else {
upCount++
}
}
// pass 1 - count allocated servers only, since those can't be touched
for _, gs := range list {
if isAllocated(gs) {
upCount++
continue
}
}
// pass 2 - handle all other statuses
for _, gs := range list {
if isAllocated(gs) {
// already handled above
continue
}
// GS being deleted counts towards target replica count.
if !gs.ObjectMeta.DeletionTimestamp.IsZero() {
continue
}
switch gs.Status.State {
case v1alpha1.GameServerStatePortAllocation:
podPendingCount++
handleGameServerUp(gs)
case v1alpha1.GameServerStateCreating:
podPendingCount++
handleGameServerUp(gs)
case v1alpha1.GameServerStateStarting:
podPendingCount++
handleGameServerUp(gs)
case v1alpha1.GameServerStateScheduled:
podPendingCount++
handleGameServerUp(gs)
case v1alpha1.GameServerStateRequestReady:
handleGameServerUp(gs)
case v1alpha1.GameServerStateReady:
handleGameServerUp(gs)
case v1alpha1.GameServerStateShutdown:
// will be deleted soon
handleGameServerUp(gs)
// GameServerStateAllocated - already handled above
case v1alpha1.GameServerStateError, v1alpha1.GameServerStateUnhealthy:
scheduleDeletion(gs)
default:
// unrecognized state, assume it's up.
handleGameServerUp(gs)
}
}
var partialReconciliation bool
var numServersToAdd int
if upCount < targetReplicaCount {
numServersToAdd = targetReplicaCount - upCount
originalNumServersToAdd := numServersToAdd
if numServersToAdd > maxCreations {
numServersToAdd = maxCreations
}
if numServersToAdd+podPendingCount > maxPending {
numServersToAdd = maxPending - podPendingCount
if numServersToAdd < 0 {
numServersToAdd = 0
}
}
if originalNumServersToAdd != numServersToAdd {
partialReconciliation = true
}
}
if len(toDelete) > maxDeletions {
// we have to pick which GS to delete, let's delete the newest ones first.
sort.Slice(toDelete, func(i, j int) bool {
return toDelete[i].ObjectMeta.CreationTimestamp.After(toDelete[j].ObjectMeta.CreationTimestamp.Time)
})
toDelete = toDelete[0:maxDeletions]
partialReconciliation = true
}
return numServersToAdd, toDelete, partialReconciliation
}
func isAllocated(gs *v1alpha1.GameServer) bool {
return gs.ObjectMeta.DeletionTimestamp == nil && gs.Status.State == v1alpha1.GameServerStateAllocated
}
// addMoreGameServers adds diff more GameServers to the set
func (c *Controller) addMoreGameServers(gsSet *v1alpha1.GameServerSet, count int) error {
c.logger.WithField("count", count).WithField("gameserverset", gsSet.ObjectMeta.Name).Info("Adding more gameservers")
return parallelize(newGameServersChannel(count, gsSet), maxCreationParalellism, func(gs *v1alpha1.GameServer) error {
gs, err := c.gameServerGetter.GameServers(gs.Namespace).Create(gs)
if err != nil {
return errors.Wrapf(err, "error creating gameserver for gameserverset %s", gsSet.ObjectMeta.Name)
}
c.stateCache.forGameServerSet(gsSet).created(gs)
c.recorder.Eventf(gsSet, corev1.EventTypeNormal, "SuccessfulCreate", "Created gameserver: %s", gs.ObjectMeta.Name)
return nil
})
}
func (c *Controller) deleteGameServers(gsSet *v1alpha1.GameServerSet, toDelete []*v1alpha1.GameServer) error {
c.logger.WithField("diff", len(toDelete)).WithField("gameserverset", gsSet.ObjectMeta.Name).Info("Deleting gameservers")
return parallelize(gameServerListToChannel(toDelete), maxDeletionParallelism, func(gs *v1alpha1.GameServer) error {
// We should not delete the gameservers directly buy set their state to shutdown and let the gameserver controller to delete
gsCopy := gs.DeepCopy()
gsCopy.Status.State = v1alpha1.GameServerStateShutdown
_, err := c.gameServerGetter.GameServers(gs.Namespace).Update(gsCopy)
if err != nil {
return errors.Wrapf(err, "error updating gameserver %s from status %s to Shutdown status.", gs.ObjectMeta.Name, gs.Status.State)
}
c.stateCache.forGameServerSet(gsSet).deleted(gs)
c.recorder.Eventf(gsSet, corev1.EventTypeNormal, "SuccessfulDelete", "Deleted gameserver: %s", gs.ObjectMeta.Name)
return nil
})
}
func newGameServersChannel(n int, gsSet *v1alpha1.GameServerSet) chan *v1alpha1.GameServer {
gameServers := make(chan *v1alpha1.GameServer)
go func() {
defer close(gameServers)
for i := 0; i < n; i++ {
gameServers <- gsSet.GameServer()
}
}()
return gameServers
}
func gameServerListToChannel(list []*v1alpha1.GameServer) chan *v1alpha1.GameServer {
gameServers := make(chan *v1alpha1.GameServer)
go func() {
defer close(gameServers)
for _, gs := range list {
gameServers <- gs
}
}()
return gameServers
}
// parallelize processes a channel of game server objects, invoking the provided callback for items in the channel with the specified degree of parallelism up to a limit.
// Returns nil if all callbacks returned nil or one of the error responses, not necessarily the first one.
func parallelize(gameServers chan *v1alpha1.GameServer, parallelism int, work func(gs *v1alpha1.GameServer) error) error {
errch := make(chan error, parallelism)
var wg sync.WaitGroup
for i := 0; i < parallelism; i++ {
wg.Add(1)
go func() {
defer wg.Done()
for it := range gameServers {
err := work(it)
if err != nil {
errch <- err
break
}
}
}()
}
wg.Wait()
close(errch)
for range gameServers {
// drain any remaining game servers in the channel, in case we did not consume them all
}
// return first error from the channel, or nil if all successful.
return <-errch
}
// syncGameServerSetStatus synchronises the GameServerSet State with active GameServer counts
func (c *Controller) syncGameServerSetStatus(gsSet *v1alpha1.GameServerSet, list []*v1alpha1.GameServer) error {
return c.updateStatusIfChanged(gsSet, computeStatus(list))
}
// updateStatusIfChanged updates GameServerSet status if it's different than provided.
func (c *Controller) updateStatusIfChanged(gsSet *v1alpha1.GameServerSet, status v1alpha1.GameServerSetStatus) error {
if gsSet.Status != status {
gsSetCopy := gsSet.DeepCopy()
gsSetCopy.Status = status
_, err := c.gameServerSetGetter.GameServerSets(gsSet.ObjectMeta.Namespace).Update(gsSetCopy)
if err != nil {
return errors.Wrapf(err, "error updating status on GameServerSet %s", gsSet.ObjectMeta.Name)
}
}
return nil
}
// computeStatus computes the status of the game server set.
func computeStatus(list []*v1alpha1.GameServer) v1alpha1.GameServerSetStatus {
var status v1alpha1.GameServerSetStatus
status.Replicas = int32(len(list))
for _, gs := range list {
switch gs.Status.State {
case v1alpha1.GameServerStateReady:
status.ReadyReplicas++
case v1alpha1.GameServerStateAllocated:
status.AllocatedReplicas++
}
}
return status
}