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controller.go
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controller.go
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package deploymentconfig
import (
"fmt"
"strconv"
"github.com/golang/glog"
kapi "k8s.io/kubernetes/pkg/api"
"k8s.io/kubernetes/pkg/api/errors"
"k8s.io/kubernetes/pkg/client/record"
kclient "k8s.io/kubernetes/pkg/client/unversioned"
"k8s.io/kubernetes/pkg/runtime"
osclient "github.com/openshift/origin/pkg/client"
deployapi "github.com/openshift/origin/pkg/deploy/api"
deployutil "github.com/openshift/origin/pkg/deploy/util"
)
// DeploymentConfigController is responsible for creating a new deployment
// when:
//
// 1. The config version is > 0 and,
// 2. No deployment for the version exists.
//
// The controller reconciles deployments with the replica count specified on
// the config. The active deployment (that is, the latest successful
// deployment) will always be scaled to the config replica count. All other
// deployments will be scaled to zero.
//
// If a new version is observed for which no deployment exists, any running
// deployments will be cancelled. The controller will not attempt to scale
// running deployments.
type DeploymentConfigController struct {
// kubeClient provides acceess to Kube resources.
kubeClient kclient.Interface
// osClient provides access to OpenShift resources.
osClient osclient.Interface
// codec is used to build deployments from configs.
codec runtime.Codec
// recorder is used to record events.
recorder record.EventRecorder
}
// fatalError is an error which can't be retried.
type fatalError string
// transientError is an error which should always be retried (indefinitely).
type transientError string
func (e fatalError) Error() string {
return fmt.Sprintf("fatal error handling deployment config: %s", string(e))
}
func (e transientError) Error() string {
return "transient error handling deployment config: " + string(e)
}
func NewDeploymentConfigController(kubeClient kclient.Interface, osClient osclient.Interface, codec runtime.Codec, recorder record.EventRecorder) *DeploymentConfigController {
return &DeploymentConfigController{
kubeClient: kubeClient,
osClient: osClient,
codec: codec,
recorder: recorder,
}
}
func (c *DeploymentConfigController) Handle(config *deployapi.DeploymentConfig) error {
// There's nothing to reconcile until the version is nonzero.
if config.Status.LatestVersion == 0 {
glog.V(5).Infof("Waiting for first version of %s", deployutil.LabelForDeploymentConfig(config))
return nil
}
// Find all deployments owned by the deploymentConfig.
sel := deployutil.ConfigSelector(config.Name)
existingDeployments, err := c.kubeClient.ReplicationControllers(config.Namespace).List(kapi.ListOptions{LabelSelector: sel})
if err != nil {
return err
}
latestIsDeployed, latestDeployment := deployutil.LatestDeploymentInfo(config, existingDeployments)
// If the latest deployment doesn't exist yet, cancel any running
// deployments to allow them to be superceded by the new config version.
awaitingCancellations := false
if !latestIsDeployed {
for _, deployment := range existingDeployments.Items {
// Skip deployments with an outcome.
if deployutil.IsTerminatedDeployment(&deployment) {
continue
}
// Cancel running deployments.
awaitingCancellations = true
if !deployutil.IsDeploymentCancelled(&deployment) {
deployment.Annotations[deployapi.DeploymentCancelledAnnotation] = deployapi.DeploymentCancelledAnnotationValue
deployment.Annotations[deployapi.DeploymentStatusReasonAnnotation] = deployapi.DeploymentCancelledNewerDeploymentExists
_, err := c.kubeClient.ReplicationControllers(deployment.Namespace).Update(&deployment)
if err != nil {
c.recorder.Eventf(config, kapi.EventTypeWarning, "DeploymentCancellationFailed", "Failed to cancel deployment %q superceded by version %d: %s", deployment.Name, config.Status.LatestVersion, err)
} else {
c.recorder.Eventf(config, kapi.EventTypeNormal, "DeploymentCancelled", "Cancelled deployment %q superceded by version %d", deployment.Name, config.Status.LatestVersion)
}
}
}
}
// Wait for deployment cancellations before reconciling or creating a new
// deployment to avoid competing with existing deployment processes.
if awaitingCancellations {
c.recorder.Eventf(config, kapi.EventTypeNormal, "DeploymentAwaitingCancellation", "Deployment of version %d awaiting cancellation of older running deployments", config.Status.LatestVersion)
// raise a transientError so that the deployment config can be re-queued
return transientError(fmt.Sprintf("found previous inflight deployment for %s - requeuing", deployutil.LabelForDeploymentConfig(config)))
}
// If the latest deployment already exists, reconcile existing deployments
// and return early.
if latestIsDeployed {
// If the latest deployment is still running, try again later. We don't
// want to compete with the deployer.
if !deployutil.IsTerminatedDeployment(latestDeployment) {
return nil
}
return c.reconcileDeployments(existingDeployments, config)
}
// No deployments are running and the latest deployment doesn't exist, so
// create the new deployment.
deployment, err := deployutil.MakeDeployment(config, c.codec)
if err != nil {
return fatalError(fmt.Sprintf("couldn't make deployment from (potentially invalid) deployment config %s: %v", deployutil.LabelForDeploymentConfig(config), err))
}
created, err := c.kubeClient.ReplicationControllers(config.Namespace).Create(deployment)
if err != nil {
// If the deployment was already created, just move on. The cache could be
// stale, or another process could have already handled this update.
if errors.IsAlreadyExists(err) {
return nil
}
c.recorder.Eventf(config, kapi.EventTypeWarning, "DeploymentCreationFailed", "Couldn't deploy version %d: %s", config.Status.LatestVersion, err)
return fmt.Errorf("couldn't create deployment for deployment config %s: %v", deployutil.LabelForDeploymentConfig(config), err)
}
c.recorder.Eventf(config, kapi.EventTypeNormal, "DeploymentCreated", "Created new deployment %q for version %d", created.Name, config.Status.LatestVersion)
return nil
}
// reconcileDeployments reconciles existing deployment replica counts which
// could have diverged outside the deployment process (e.g. due to auto or
// manual scaling, or partial deployments). The active deployment is the last
// successful deployment, not necessarily the latest in terms of the config
// version. The active deployment replica count should follow the config, and
// all other deployments should be scaled to zero.
//
// Previously, scaling behavior was that the config replica count was used
// only for initial deployments and the active deployment had to be scaled up
// directly. To continue supporting that old behavior we must detect when the
// deployment has been directly manipulated, and if so, preserve the directly
// updated value and sync the config with the deployment.
func (c *DeploymentConfigController) reconcileDeployments(existingDeployments *kapi.ReplicationControllerList, config *deployapi.DeploymentConfig) error {
latestIsDeployed, latestDeployment := deployutil.LatestDeploymentInfo(config, existingDeployments)
if !latestIsDeployed {
// We shouldn't be reconciling if the latest deployment hasn't been
// created; this is enforced on the calling side, but double checking
// can't hurt.
return nil
}
activeDeployment := deployutil.ActiveDeployment(config, existingDeployments)
// Compute the replica count for the active deployment (even if the active
// deployment doesn't exist). The active replica count is the value that
// should be assigned to the config, to allow the replica propagation to
// flow downward from the config.
//
// By default we'll assume the config replicas should be used to update the
// active deployment except in special cases (like first sync or externally
// updated deployments.)
activeReplicas := config.Spec.Replicas
source := "the deploymentConfig itself (no change)"
activeDeploymentExists := activeDeployment != nil
activeDeploymentIsLatest := activeDeploymentExists && activeDeployment.Name == latestDeployment.Name
latestDesiredReplicas, latestHasDesiredReplicas := deployutil.DeploymentDesiredReplicas(latestDeployment)
switch {
case activeDeploymentExists && activeDeploymentIsLatest:
// The active/latest deployment follows the config unless this is its first
// sync or if an external change to the deployment replicas is detected.
lastActiveReplicas, hasLastActiveReplicas := deployutil.DeploymentReplicas(activeDeployment)
if !hasLastActiveReplicas || lastActiveReplicas != activeDeployment.Spec.Replicas {
activeReplicas = activeDeployment.Spec.Replicas
source = fmt.Sprintf("the latest/active deployment %q which was scaled directly or has not previously been synced", deployutil.LabelForDeployment(activeDeployment))
}
case activeDeploymentExists && !activeDeploymentIsLatest:
// The active/non-latest deployment follows the config if it was
// previously synced; if this is the first sync, infer what the config
// value should be based on either the latest desired or whatever the
// deployment is currently scaled to.
_, hasLastActiveReplicas := deployutil.DeploymentReplicas(activeDeployment)
if hasLastActiveReplicas {
break
}
if latestHasDesiredReplicas {
activeReplicas = latestDesiredReplicas
source = fmt.Sprintf("the desired replicas of latest deployment %q which has not been previously synced", deployutil.LabelForDeployment(latestDeployment))
} else if activeDeployment.Spec.Replicas > 0 {
activeReplicas = activeDeployment.Spec.Replicas
source = fmt.Sprintf("the active deployment %q which has not been previously synced", deployutil.LabelForDeployment(activeDeployment))
}
case !activeDeploymentExists && latestHasDesiredReplicas:
// If there's no active deployment, use the latest desired, if available.
activeReplicas = latestDesiredReplicas
source = fmt.Sprintf("the desired replicas of latest deployment %q with no active deployment", deployutil.LabelForDeployment(latestDeployment))
}
// Bring the config in sync with the deployment. Once we know the config
// accurately represents the desired replica count of the active deployment,
// we can safely reconcile deployments.
//
// If the deployment config is test, never update the deployment config based
// on deployments, since test behavior overrides user scaling.
switch {
case config.Spec.Replicas == activeReplicas:
case config.Spec.Test:
glog.V(4).Infof("Detected changed replicas for test deploymentConfig %q, ignoring that change", deployutil.LabelForDeploymentConfig(config))
default:
oldReplicas := config.Spec.Replicas
config.Spec.Replicas = activeReplicas
_, err := c.osClient.DeploymentConfigs(config.Namespace).Update(config)
if err != nil {
return err
}
glog.V(4).Infof("Synced deploymentConfig %q replicas from %d to %d based on %s", deployutil.LabelForDeploymentConfig(config), oldReplicas, activeReplicas, source)
}
// Reconcile deployments. The active deployment follows the config, and all
// other deployments should be scaled to zero.
for _, deployment := range existingDeployments.Items {
isActiveDeployment := activeDeployment != nil && deployment.Name == activeDeployment.Name
oldReplicaCount := deployment.Spec.Replicas
newReplicaCount := 0
if isActiveDeployment {
newReplicaCount = activeReplicas
}
if config.Spec.Test {
glog.V(4).Infof("Deployment config %q is test and deployment %q will be scaled down", deployutil.LabelForDeploymentConfig(config), deployutil.LabelForDeployment(&deployment))
newReplicaCount = 0
}
lastReplicas, hasLastReplicas := deployutil.DeploymentReplicas(&deployment)
// Only update if necessary.
if !hasLastReplicas || newReplicaCount != oldReplicaCount || lastReplicas != newReplicaCount {
deployment.Spec.Replicas = newReplicaCount
deployment.Annotations[deployapi.DeploymentReplicasAnnotation] = strconv.Itoa(newReplicaCount)
_, err := c.kubeClient.ReplicationControllers(deployment.Namespace).Update(&deployment)
if err != nil {
c.recorder.Eventf(config, kapi.EventTypeWarning, "DeploymentScaleFailed",
"Failed to scale deployment %q from %d to %d: %s", deployment.Name, oldReplicaCount, newReplicaCount, err)
return err
}
// Only report scaling events if we changed the replica count.
if oldReplicaCount != newReplicaCount {
c.recorder.Eventf(config, kapi.EventTypeNormal, "DeploymentScaled",
"Scaled deployment %q from %d to %d", deployment.Name, oldReplicaCount, newReplicaCount)
} else {
glog.V(4).Infof("Updated deployment %q replica annotation to match current replica count %d", deployutil.LabelForDeployment(&deployment), newReplicaCount)
}
}
}
return nil
}