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rolling.go
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rolling.go
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package rolling
import (
"fmt"
"time"
"github.com/golang/glog"
kapi "k8s.io/kubernetes/pkg/api"
kclient "k8s.io/kubernetes/pkg/client"
"k8s.io/kubernetes/pkg/kubectl"
"k8s.io/kubernetes/pkg/runtime"
"k8s.io/kubernetes/pkg/util"
deployapi "github.com/openshift/origin/pkg/deploy/api"
strat "github.com/openshift/origin/pkg/deploy/strategy"
stratsupport "github.com/openshift/origin/pkg/deploy/strategy/support"
deployutil "github.com/openshift/origin/pkg/deploy/util"
)
// TODO: This should perhaps be made public upstream. See:
// https://github.com/kubernetes/kubernetes/issues/7851
const sourceIdAnnotation = "kubectl.kubernetes.io/update-source-id"
// RollingDeploymentStrategy is a Strategy which implements rolling
// deployments using the upstream Kubernetes RollingUpdater.
//
// Currently, there are some caveats:
//
// 1. When there is no existing prior deployment, deployment delegates to
// another strategy.
// 2. The interface to the RollingUpdater is not very clean.
//
// These caveats can be resolved with future upstream refactorings to
// RollingUpdater[1][2].
//
// [1] https://github.com/kubernetes/kubernetes/pull/7183
// [2] https://github.com/kubernetes/kubernetes/issues/7851
type RollingDeploymentStrategy struct {
// initialStrategy is used when there are no prior deployments.
initialStrategy acceptingDeploymentStrategy
// client is used to deal with ReplicationControllers.
client kclient.Interface
// rollingUpdate knows how to perform a rolling update.
rollingUpdate func(config *kubectl.RollingUpdaterConfig) error
// codec is used to access the encoded config on a deployment.
codec runtime.Codec
// hookExecutor can execute a lifecycle hook.
hookExecutor hookExecutor
// getUpdateAcceptor returns an UpdateAcceptor to verify the first replica
// of the deployment.
getUpdateAcceptor func(timeout time.Duration) strat.UpdateAcceptor
}
// acceptingDeploymentStrategy is a DeploymentStrategy which accepts an
// injected UpdateAcceptor as part of the deploy function. This is a hack to
// support using the Recreate strategy for initial deployments and should be
// removed when https://github.com/kubernetes/kubernetes/pull/7183 is
// fixed.
type acceptingDeploymentStrategy interface {
DeployWithAcceptor(from *kapi.ReplicationController, to *kapi.ReplicationController, desiredReplicas int, updateAcceptor strat.UpdateAcceptor) error
}
// AcceptorInterval is how often the UpdateAcceptor should check for
// readiness.
const AcceptorInterval = 1 * time.Second
// NewRollingDeploymentStrategy makes a new RollingDeploymentStrategy.
func NewRollingDeploymentStrategy(namespace string, client kclient.Interface, codec runtime.Codec, initialStrategy acceptingDeploymentStrategy) *RollingDeploymentStrategy {
return &RollingDeploymentStrategy{
codec: codec,
initialStrategy: initialStrategy,
client: client,
rollingUpdate: func(config *kubectl.RollingUpdaterConfig) error {
updater := kubectl.NewRollingUpdater(namespace, client)
return updater.Update(config)
},
hookExecutor: &stratsupport.HookExecutor{
PodClient: &stratsupport.HookExecutorPodClientImpl{
CreatePodFunc: func(namespace string, pod *kapi.Pod) (*kapi.Pod, error) {
return client.Pods(namespace).Create(pod)
},
PodWatchFunc: func(namespace, name, resourceVersion string, stopChannel chan struct{}) func() *kapi.Pod {
return stratsupport.NewPodWatch(client, namespace, name, resourceVersion, stopChannel)
},
},
},
getUpdateAcceptor: func(timeout time.Duration) strat.UpdateAcceptor {
return stratsupport.NewAcceptNewlyObservedReadyPods(client, timeout, AcceptorInterval)
},
}
}
func (s *RollingDeploymentStrategy) Deploy(from *kapi.ReplicationController, to *kapi.ReplicationController, desiredReplicas int) error {
config, err := deployutil.DecodeDeploymentConfig(to, s.codec)
if err != nil {
return fmt.Errorf("couldn't decode DeploymentConfig from deployment %s: %v", deployutil.LabelForDeployment(to), err)
}
params := config.Template.Strategy.RollingParams
updateAcceptor := s.getUpdateAcceptor(time.Duration(*params.TimeoutSeconds) * time.Second)
// If there's no prior deployment, delegate to another strategy since the
// rolling updater only supports transitioning between two deployments.
//
// Hook support is duplicated here for now. When the rolling updater can
// handle initial deployments, all of this code can go away.
if from == nil {
// Execute any pre-hook.
if params.Pre != nil {
err := s.hookExecutor.Execute(params.Pre, to, "prehook")
if err != nil {
return fmt.Errorf("Pre hook failed: %s", err)
}
glog.Infof("Pre hook finished")
}
// Execute the delegate strategy.
err := s.initialStrategy.DeployWithAcceptor(from, to, desiredReplicas, updateAcceptor)
if err != nil {
return err
}
// Execute any post-hook. Errors are logged and ignored.
if params.Post != nil {
err := s.hookExecutor.Execute(params.Post, to, "posthook")
if err != nil {
util.HandleError(fmt.Errorf("post hook failed: %s", err))
} else {
glog.Infof("Post hook finished")
}
}
// All done.
return nil
}
// Prepare for a rolling update.
// Execute any pre-hook.
if params.Pre != nil {
err := s.hookExecutor.Execute(params.Pre, to, "prehook")
if err != nil {
return fmt.Errorf("pre hook failed: %s", err)
}
glog.Infof("Pre hook finished")
}
// HACK: Assign the source ID annotation that the rolling updater expects,
// unless it already exists on the deployment.
//
// Related upstream issue:
// https://github.com/kubernetes/kubernetes/pull/7183
to, err = s.client.ReplicationControllers(to.Namespace).Get(to.Name)
if err != nil {
return fmt.Errorf("couldn't look up deployment %s: %s", deployutil.LabelForDeployment(to), err)
}
if _, hasSourceId := to.Annotations[sourceIdAnnotation]; !hasSourceId {
to.Annotations[sourceIdAnnotation] = fmt.Sprintf("%s:%s", from.Name, from.ObjectMeta.UID)
if updated, err := s.client.ReplicationControllers(to.Namespace).Update(to); err != nil {
return fmt.Errorf("couldn't assign source annotation to deployment %s: %v", deployutil.LabelForDeployment(to), err)
} else {
to = updated
}
}
// HACK: There's a validation in the rolling updater which assumes that when
// an existing RC is supplied, it will have >0 replicas- a validation which
// is then disregarded as the desired count is obtained from the annotation
// on the RC. For now, fake it out by just setting replicas to 1.
//
// Related upstream issue:
// https://github.com/kubernetes/kubernetes/pull/7183
to.Spec.Replicas = 1
// Perform a rolling update.
rollingConfig := &kubectl.RollingUpdaterConfig{
Out: &rollingUpdaterWriter{},
OldRc: from,
NewRc: to,
UpdatePeriod: time.Duration(*params.UpdatePeriodSeconds) * time.Second,
Interval: time.Duration(*params.IntervalSeconds) * time.Second,
Timeout: time.Duration(*params.TimeoutSeconds) * time.Second,
CleanupPolicy: kubectl.PreserveRollingUpdateCleanupPolicy,
MaxSurge: params.MaxSurge,
MaxUnavailable: params.MaxUnavailable,
}
err = s.rollingUpdate(rollingConfig)
if err != nil {
return err
}
// Execute any post-hook. Errors are logged and ignored.
if params.Post != nil {
err := s.hookExecutor.Execute(params.Post, to, "posthook")
if err != nil {
util.HandleError(fmt.Errorf("Post hook failed: %s", err))
} else {
glog.Info("Post hook finished")
}
}
return nil
}
// rollingUpdaterWriter is an io.Writer that delegates to glog.
type rollingUpdaterWriter struct{}
func (w *rollingUpdaterWriter) Write(p []byte) (n int, err error) {
glog.Info(fmt.Sprintf("RollingUpdater: %s", p))
return len(p), nil
}
// hookExecutor knows how to execute a deployment lifecycle hook.
type hookExecutor interface {
Execute(hook *deployapi.LifecycleHook, deployment *kapi.ReplicationController, label string) error
}
// hookExecutorImpl is a pluggable hookExecutor.
type hookExecutorImpl struct {
executeFunc func(hook *deployapi.LifecycleHook, deployment *kapi.ReplicationController, label string) error
}
// Execute executes the provided lifecycle hook
func (i *hookExecutorImpl) Execute(hook *deployapi.LifecycleHook, deployment *kapi.ReplicationController, label string) error {
return i.executeFunc(hook, deployment, label)
}