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Implementing cross cluster allocation request #757

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merged 1 commit into from
May 7, 2019
Merged

Implementing cross cluster allocation request #757

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2 changes: 1 addition & 1 deletion cmd/controller/main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -200,7 +200,7 @@ func main() {
faController := fleetallocation.NewController(wh, allocationMutex,
kubeClient, extClient, agonesClient, agonesInformerFactory)
gasController := gameserverallocations.NewController(api, health, gsCounter, topNGSForAllocation,
kubeClient, agonesClient, agonesInformerFactory)
kubeClient, kubeInformerFactory, agonesClient, agonesInformerFactory)
fasController := fleetautoscalers.NewController(wh, health,
kubeClient, extClient, agonesClient, agonesInformerFactory)

Expand Down
123 changes: 115 additions & 8 deletions pkg/gameserverallocations/controller.go
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,10 @@
package gameserverallocations

import (
"bytes"
"crypto/tls"
"crypto/x509"
"encoding/json"
"fmt"
"io/ioutil"
"math/rand"
Expand Down Expand Up @@ -48,9 +52,11 @@ import (
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apimachinery/pkg/runtime/serializer"
"k8s.io/apimachinery/pkg/util/wait"
"k8s.io/client-go/informers"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/kubernetes/scheme"
typedcorev1 "k8s.io/client-go/kubernetes/typed/core/v1"
corev1lister "k8s.io/client-go/listers/core/v1"
"k8s.io/client-go/tools/cache"
"k8s.io/client-go/tools/record"
)
Expand All @@ -63,6 +69,12 @@ var (
ErrConflictInGameServerSelection = errors.New("The Gameserver was already allocated")
)

const (
secretClientCertName = "client-cert"
secretClientKeyName = "client-key"
secretCaCertName = "ca-cert"
)

// Controller is a the GameServerAllocation controller
type Controller struct {
baseLogger *logrus.Entry
Expand All @@ -75,6 +87,7 @@ type Controller struct {
gameServerGetter getterv1alpha1.GameServersGetter
gameServerLister listerv1alpha1.GameServerLister
allocationPolicyLister multiclusterlisterv1alpha1.GameServerAllocationPolicyLister
secretLister corev1lister.SecretLister
stop <-chan struct{}
workerqueue *workerqueue.WorkerQueue
recorder record.EventRecorder
Expand All @@ -98,6 +111,7 @@ func NewController(apiServer *apiserver.APIServer,
counter *gameservers.PerNodeCounter,
topNGameServerCnt int,
kubeClient kubernetes.Interface,
kubeInformerFactory informers.SharedInformerFactory,
agonesClient versioned.Interface,
agonesInformerFactory externalversions.SharedInformerFactory,
) *Controller {
Expand All @@ -110,6 +124,7 @@ func NewController(apiServer *apiserver.APIServer,
gameServerGetter: agonesClient.StableV1alpha1(),
gameServerLister: agonesInformer.GameServers().Lister(),
allocationPolicyLister: agonesInformerFactory.Multicluster().V1alpha1().GameServerAllocationPolicies().Lister(),
secretLister: kubeInformerFactory.Core().V1().Secrets().Lister(),
}
c.baseLogger = runtime.NewLoggerWithType(c)
c.workerqueue = workerqueue.NewWorkerQueue(c.syncGameServers, c.baseLogger, logfields.GameServerKey, stable.GroupName+".GameServerUpdateController")
Expand Down Expand Up @@ -290,19 +305,21 @@ func (c *Controller) allocateFromLocalCluster(gsa *v1alpha1.GameServerAllocation

// applyMultiClusterAllocation retrieves allocation policies and iterate on policies.
// Then allocate gameservers from local or remote cluster accordingly.
func (c *Controller) applyMultiClusterAllocation(gsa *v1alpha1.GameServerAllocation) (*v1alpha1.GameServerAllocation, error) {
var result *v1alpha1.GameServerAllocation
func (c *Controller) applyMultiClusterAllocation(gsa *v1alpha1.GameServerAllocation) (result *v1alpha1.GameServerAllocation, err error) {

selector, err := metav1.LabelSelectorAsSelector(&gsa.Spec.MultiClusterSetting.PolicySelector)
if err != nil {
return nil, err
selector := labels.Everything()
if len(gsa.Spec.MultiClusterSetting.PolicySelector.MatchLabels)+len(gsa.Spec.MultiClusterSetting.PolicySelector.MatchExpressions) != 0 {
selector, err = metav1.LabelSelectorAsSelector(&gsa.Spec.MultiClusterSetting.PolicySelector)
if err != nil {
return nil, err
}
}

policies, err := c.allocationPolicyLister.GameServerAllocationPolicies(gsa.ObjectMeta.Namespace).List(selector)
if err != nil {
return nil, err
} else if len(policies) == 0 {
return c.allocateFromLocalCluster(gsa)
return nil, errors.New("no multi-cluster allocation policy is specified")
}

it := multiclusterv1alpha1.NewConnectionInfoIterator(policies)
Expand All @@ -328,8 +345,98 @@ func (c *Controller) applyMultiClusterAllocation(gsa *v1alpha1.GameServerAllocat
// allocateFromRemoteCluster allocates gameservers from a remote cluster by making
// an http call to allocation service in that cluster.
func (c *Controller) allocateFromRemoteCluster(gsa v1alpha1.GameServerAllocation, connectionInfo *multiclusterv1alpha1.ClusterConnectionInfo, namespace string) (*v1alpha1.GameServerAllocation, error) {
// TODO: implement getting secrets and making rest call to remote cluster
return nil, nil
var gsaResult v1alpha1.GameServerAllocation

// TODO: handle converting error to apiserver error
// TODO: cache the client
client, err := c.createRemoteClusterRestClient(namespace, connectionInfo.SecretName)
if err != nil {
return nil, err
}

// Forward the game server allocation request to another cluster,
// and disable multicluster settings to avoid the target cluster
// forward the allocation request again.
gsa.Spec.MultiClusterSetting.Enabled = false
body, err := json.Marshal(gsa)
if err != nil {
return nil, err
}

// TODO: Retry on transient error --> response.StatusCode >= 500
response, err := client.Post(connectionInfo.AllocationEndpoint, "application/json", bytes.NewBuffer(body))
if err != nil {
return nil, err
}
defer response.Body.Close() // nolint: errcheck

data, err := ioutil.ReadAll(response.Body)
if err != nil {
return nil, err
}
if response.StatusCode >= 400 {
return nil, errors.New(string(data))
}

err = json.Unmarshal(data, &gsaResult)
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nit:

this can help avoid having to explicitly read data:

if err := json.NewUnmarshaler(response.Body).Decode(&gsaResult); err != nil {
  return nil, fmt.Errors("unable to parse request: %v", err)
}

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@pooneh-m pooneh-m May 7, 2019 •
edited
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The problem is this would fail for error cases that does not decode to gsa. So it actually needs the two step deserialization.

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not sure what's going on here, then

is it important to return data in error string? if so, can you add some comments?

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The data is returned as an error string only for http status 4xx and 5xx. In that case the response body is expected to contain error and not GSA message. Therefore Decode(&gsaResult) would fail to parse the response body as GSA.
I'll add comment in the next PR since this is already merged.

if err != nil {
return nil, err
}

return &gsaResult, nil
}

// createRemoteClusterRestClient creates a rest client with proper certs to make a remote call.
func (c *Controller) createRemoteClusterRestClient(namespace, secretName string) (*http.Client, error) {
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clientCert, clientKey, caCert, err := c.getClientCertificates(namespace, secretName)
if err != nil {
return nil, err
}
if clientCert == nil || clientKey == nil {
return nil, fmt.Errorf("missing client certificate key pair in secret %s", secretName)
}

// Load client cert
cert, err := tls.X509KeyPair(clientCert, clientKey)
if err != nil {
return nil, err
}

tlsConfig := &tls.Config{Certificates: []tls.Certificate{cert}}
if len(caCert) != 0 {
// Load CA cert, if provided and trust the server certificate.
// This is required for self-signed certs.
tlsConfig.RootCAs = x509.NewCertPool()
ca, err := x509.ParseCertificate(caCert)
if err != nil {
return nil, err
}
tlsConfig.RootCAs.AddCert(ca)
}

// Setup HTTPS client
return &http.Client{
Transport: &http.Transport{
TLSClientConfig: tlsConfig,
},
}, nil
}

// getClientCertificates returns the client certificates and CA cert for remote allocation cluster call
func (c *Controller) getClientCertificates(namespace, secretName string) (clientCert, clientKey, caCert []byte, err error) {
secret, err := c.secretLister.Secrets(namespace).Get(secretName)
if err != nil {
return nil, nil, nil, err
}
if secret == nil || len(secret.Data) == 0 {
return nil, nil, nil, fmt.Errorf("secert %s does not have data", secretName)
}

// Create http client using cert
clientCert = secret.Data[secretClientCertName]
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clientKey = secret.Data[secretClientKeyName]
caCert = secret.Data[secretCaCertName]
return clientCert, clientKey, caCert, nil
}

// allocationDeserialization processes the request and namespace, and attempts to deserialise its values
Expand Down
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