// MaxSurge returns the maximum surge pods a rolling deployment config can take.
func MaxSurge(config deployapi.DeploymentConfig) int32 {
if !IsRollingConfig(&config) {
return int32(0)
}
// Error caught by validation
maxSurge, _, _ := kdeplutil.ResolveFenceposts(&config.Spec.Strategy.RollingParams.MaxSurge, &config.Spec.Strategy.RollingParams.MaxUnavailable, config.Spec.Replicas)
return maxSurge
}
// Update all pods for a ReplicationController (oldRc) by creating a new
// controller (newRc) with 0 replicas, and synchronously scaling oldRc and
// newRc until oldRc has 0 replicas and newRc has the original # of desired
// replicas. Cleanup occurs based on a RollingUpdaterCleanupPolicy.
//
// Each interval, the updater will attempt to make progress however it can
// without violating any availability constraints defined by the config. This
// means the amount scaled up or down each interval will vary based on the
// timeliness of readiness and the updater will always try to make progress,
// even slowly.
//
// If an update from newRc to oldRc is already in progress, we attempt to
// drive it to completion. If an error occurs at any step of the update, the
// error will be returned.
//
// A scaling event (either up or down) is considered progress; if no progress
// is made within the config.Timeout, an error is returned.
//
// TODO: make this handle performing a rollback of a partially completed
// rollout.
func (r *RollingUpdater) Update(config *RollingUpdaterConfig) error {
out := config.Out
oldRc := config.OldRc
scaleRetryParams := NewRetryParams(config.Interval, config.Timeout)
// Find an existing controller (for continuing an interrupted update) or
// create a new one if necessary.
sourceId := fmt.Sprintf("%s:%s", oldRc.Name, oldRc.UID)
newRc, existed, err := r.getOrCreateTargetController(config.NewRc, sourceId)
if err != nil {
return err
}
if existed {
fmt.Fprintf(out, "Continuing update with existing controller %s.\n", newRc.Name)
} else {
fmt.Fprintf(out, "Created %s\n", newRc.Name)
}
// Extract the desired replica count from the controller.
desiredAnnotation, err := strconv.Atoi(newRc.Annotations[desiredReplicasAnnotation])
if err != nil {
return fmt.Errorf("Unable to parse annotation for %s: %s=%s",
newRc.Name, desiredReplicasAnnotation, newRc.Annotations[desiredReplicasAnnotation])
}
desired := int32(desiredAnnotation)
// Extract the original replica count from the old controller, adding the
// annotation if it doesn't yet exist.
_, hasOriginalAnnotation := oldRc.Annotations[originalReplicasAnnotation]
if !hasOriginalAnnotation {
existing, err := r.rcClient.ReplicationControllers(oldRc.Namespace).Get(oldRc.Name)
if err != nil {
return err
}
originReplicas := strconv.Itoa(int(existing.Spec.Replicas))
applyUpdate := func(rc *api.ReplicationController) {
if rc.Annotations == nil {
rc.Annotations = map[string]string{}
}
rc.Annotations[originalReplicasAnnotation] = originReplicas
}
if oldRc, err = updateRcWithRetries(r.rcClient, existing.Namespace, existing, applyUpdate); err != nil {
return err
}
}
// maxSurge is the maximum scaling increment and maxUnavailable are the maximum pods
// that can be unavailable during a rollout.
maxSurge, maxUnavailable, err := deploymentutil.ResolveFenceposts(&config.MaxSurge, &config.MaxUnavailable, desired)
if err != nil {
return err
}
// Validate maximums.
if desired > 0 && maxUnavailable == 0 && maxSurge == 0 {
return fmt.Errorf("one of maxSurge or maxUnavailable must be specified")
}
// The minimum pods which must remain available throughout the update
// calculated for internal convenience.
minAvailable := int32(integer.IntMax(0, int(desired-maxUnavailable)))
// If the desired new scale is 0, then the max unavailable is necessarily
// the effective scale of the old RC regardless of the configuration
// (equivalent to 100% maxUnavailable).
if desired == 0 {
maxUnavailable = oldRc.Spec.Replicas
minAvailable = 0
}
fmt.Fprintf(out, "Scaling up %s from %d to %d, scaling down %s from %d to 0 (keep %d pods available, don't exceed %d pods)\n",
newRc.Name, newRc.Spec.Replicas, desired, oldRc.Name, oldRc.Spec.Replicas, minAvailable, desired+maxSurge)
// give a caller incremental notification and allow them to exit early
goal := desired - newRc.Spec.Replicas
if goal < 0 {
goal = -goal
}
progress := func(complete bool) error {
if config.OnProgress == nil {
return nil
}
progress := desired - newRc.Spec.Replicas
if progress < 0 {
progress = -progress
}
percentage := 100
if !complete && goal > 0 {
percentage = int((goal - progress) * 100 / goal)
}
return config.OnProgress(oldRc, newRc, percentage)
}
// Scale newRc and oldRc until newRc has the desired number of replicas and
// oldRc has 0 replicas.
progressDeadline := time.Now().UnixNano() + config.Timeout.Nanoseconds()
for newRc.Spec.Replicas != desired || oldRc.Spec.Replicas != 0 {
// Store the existing replica counts for progress timeout tracking.
newReplicas := newRc.Spec.Replicas
oldReplicas := oldRc.Spec.Replicas
// Scale up as much as possible.
scaledRc, err := r.scaleUp(newRc, oldRc, desired, maxSurge, maxUnavailable, scaleRetryParams, config)
if err != nil {
return err
}
newRc = scaledRc
// notify the caller if necessary
if err := progress(false); err != nil {
return err
}
// Wait between scaling operations for things to settle.
time.Sleep(config.UpdatePeriod)
// Scale down as much as possible.
scaledRc, err = r.scaleDown(newRc, oldRc, desired, minAvailable, maxUnavailable, maxSurge, config)
if err != nil {
return err
}
oldRc = scaledRc
// notify the caller if necessary
if err := progress(false); err != nil {
return err
}
// If we are making progress, continue to advance the progress deadline.
// Otherwise, time out with an error.
progressMade := (newRc.Spec.Replicas != newReplicas) || (oldRc.Spec.Replicas != oldReplicas)
if progressMade {
progressDeadline = time.Now().UnixNano() + config.Timeout.Nanoseconds()
} else if time.Now().UnixNano() > progressDeadline {
return fmt.Errorf("timed out waiting for any update progress to be made")
}
}
// notify the caller if necessary
if err := progress(true); err != nil {
return err
}
// Housekeeping and cleanup policy execution.
return r.cleanup(oldRc, newRc, config)
}