Implement progressive promotion

artifacts/flagger/crd.yaml

@@ -562,7 +562,10 @@ spec:
  description: Max traffic percentage routed to canary
  type: number
  stepWeight:
- description: Incremental traffic percentage step
+ description: Incremental traffic percentage step for the analysis phase
+ type: number
+ stepWeightPromotion:
+ description: Incremental traffic percentage step for the promotion phase
  type: number
  mirror:
  description: Mirror traffic to canary

charts/flagger/crds/crd.yaml

@@ -562,7 +562,10 @@ spec:
  description: Max traffic percentage routed to canary
  type: number
  stepWeight:
- description: Incremental traffic percentage step
+ description: Incremental traffic percentage step for the analysis phase
+ type: number
+ stepWeightPromotion:
+ description: Incremental traffic percentage step for the promotion phase
  type: number
  mirror:
  description: Mirror traffic to canary

docs/gitbook/usage/deployment-strategies.md

@@ -43,13 +43,16 @@ Spec:
  # canary increment step
  # percentage (0-100)
  stepWeight: 2
+ # promotion increment step (default 100)
+ # percentage (0-100)
+ stepWeightPromotion: 100
  # deploy straight to production without
  # the metrics and webhook checks
  skipAnalysis: false
 ```
 
 The above analysis, if it succeeds, will run for 25 minutes while validating the HTTP metrics and webhooks every minute.
-You can determine the minimum time that it takes to validate and promote a canary deployment using this formula:
+You can determine the minimum time it takes to validate and promote a canary deployment using this formula:
 
 ```
 interval * (maxWeight / stepWeight)
@@ -61,6 +64,10 @@ And the time it takes for a canary to be rollback when the metrics or webhook ch
 interval * threshold 
 ```
 
+When `stepWeightPromotion` is specified, the promotion phase happens in stages,
+the traffic is routed back to the primary pods in a progressive manner,
+the primary weight is increased until it reaches 100%.
+
 In emergency cases, you may want to skip the analysis phase and ship changes directly to production. 
 At any time you can set the `spec.skipAnalysis: true`. 
 When skip analysis is enabled, Flagger checks if the canary deployment is healthy and 

docs/gitbook/usage/how-it-works.md

@@ -311,6 +311,9 @@ Spec:
  # canary increment step
  # percentage (0-100)
  stepWeight:
+ # promotion increment step
+ # percentage (0-100)
+ stepWeightPromotion:
  # total number of iterations
  # used for A/B Testing and Blue/Green
  iterations:

kustomize/base/flagger/crd.yaml

@@ -562,7 +562,10 @@ spec:
  description: Max traffic percentage routed to canary
  type: number
  stepWeight:
- description: Incremental traffic percentage step
+ description: Incremental traffic percentage step for the analysis phase
+ type: number
+ stepWeightPromotion:
+ description: Incremental traffic percentage step for the promotion phase
  type: number
  mirror:
  description: Mirror traffic to canary

pkg/apis/flagger/v1beta1/canary.go

@@ -203,10 +203,14 @@ type CanaryAnalysis struct {
  // +optional
  MaxWeight int `json:"maxWeight,omitempty"`
 
- // Incremental traffic percentage step
+ // Incremental traffic percentage step for analysis phase
  // +optional
  StepWeight int `json:"stepWeight,omitempty"`
 
+ // Incremental traffic percentage step for promotion phase
+ // +optional
+ StepWeightPromotion int `json:"stepWeightPromotion,omitempty"`
+
  // Max number of failed checks before the canary is terminated
  Threshold int `json:"threshold"`
 

pkg/controller/scheduler.go

@@ -251,23 +251,9 @@ func (c *Controller) advanceCanary(name string, namespace string) {
  }
  }
 
- // route all traffic to primary if analysis has succeeded
+ // route traffic back to primary if analysis has succeeded
  if cd.Status.Phase == flaggerv1.CanaryPhasePromoting {
- if provider != "kubernetes" {
- c.recordEventInfof(cd, "Routing all traffic to primary")
- if err := meshRouter.SetRoutes(cd, 100, 0, false); err != nil {
- c.recordEventWarningf(cd, "%v", err)
- return
- }
- c.recorder.SetWeight(cd, 100, 0)
- }
-
- // update status phase
- if err := canaryController.SetStatusPhase(cd, flaggerv1.CanaryPhaseFinalising); err != nil {
- c.recordEventWarningf(cd, "%v", err)
- return
- }
-
+ c.runPromotionTrafficShift(cd, canaryController, meshRouter, provider, canaryWeight, primaryWeight)
  return
  }
 
@@ -332,7 +318,7 @@ func (c *Controller) advanceCanary(name string, namespace string) {
  }
 
  // use blue/green strategy for kubernetes provider
- if provider == "kubernetes" {
+ if provider == flaggerv1.KubernetesProvider {
  if len(cd.GetAnalysis().Match) > 0 {
  c.recordEventWarningf(cd, "A/B testing is not supported when using the kubernetes provider")
  cd.GetAnalysis().Match = nil
@@ -363,6 +349,63 @@ func (c *Controller) advanceCanary(name string, namespace string) {
 
 }
 
+func (c *Controller) runPromotionTrafficShift(canary *flaggerv1.Canary, canaryController canary.Controller,
+ meshRouter router.Interface, provider string, canaryWeight int, primaryWeight int) {
+ // finalize promotion since no traffic shifting is possible for Kubernetes CNI
+ if provider == flaggerv1.KubernetesProvider {
+ if err := canaryController.SetStatusPhase(canary, flaggerv1.CanaryPhaseFinalising); err != nil {
+ c.recordEventWarningf(canary, "%v", err)
+ }
+ return
+ }
+
+ // route all traffic to primary in one go when promotion step wight is not set
+ if canary.Spec.Analysis.StepWeightPromotion == 0 {
+ c.recordEventInfof(canary, "Routing all traffic to primary")
+ if err := meshRouter.SetRoutes(canary, 100, 0, false); err != nil {
+ c.recordEventWarningf(canary, "%v", err)
+ return
+ }
+ c.recorder.SetWeight(canary, 100, 0)
+ if err := canaryController.SetStatusPhase(canary, flaggerv1.CanaryPhaseFinalising); err != nil {
+ c.recordEventWarningf(canary, "%v", err)
+ }
+ return
+ }
+
+ // increment the primary traffic weight until it reaches 100%
+ if canaryWeight > 0 {
+ primaryWeight += canary.GetAnalysis().StepWeightPromotion
+ if primaryWeight > 100 {
+ primaryWeight = 100
+ }
+ canaryWeight -= canary.GetAnalysis().StepWeightPromotion
+ if canaryWeight < 0 {
+ canaryWeight = 0
+ }
+ if err := meshRouter.SetRoutes(canary, primaryWeight, canaryWeight, false); err != nil {
+ c.recordEventWarningf(canary, "%v", err)
+ return
+ }
+ c.recorder.SetWeight(canary, primaryWeight, canaryWeight)
+ c.recordEventInfof(canary, "Advance %s.%s primary weight %v", canary.Name, canary.Namespace, primaryWeight)
+
+ // finalize promotion
+ if primaryWeight == 100 {
+ if err := canaryController.SetStatusPhase(canary, flaggerv1.CanaryPhaseFinalising); err != nil {
+ c.recordEventWarningf(canary, "%v", err)
+ }
+ } else {
+ if err := canaryController.SetStatusWeight(canary, canaryWeight); err != nil {
+ c.recordEventWarningf(canary, "%v", err)
+ }
+ }
+ }
+
+ return
+
+}
+
 func (c *Controller) runCanary(canary *flaggerv1.Canary, canaryController canary.Controller,
  meshRouter router.Interface, mirrored bool, canaryWeight int, primaryWeight int, maxWeight int) {
  primaryName := fmt.Sprintf("%s-primary", canary.Spec.TargetRef.Name)

pkg/controller/scheduler_deployment_test.go

@@ -134,8 +134,9 @@ func TestScheduler_DeploymentSkipAnalysis(t *testing.T) {
 func TestScheduler_DeploymentAnalysisPhases(t *testing.T) {
  cd := newDeploymentTestCanary()
  cd.Spec.Analysis = &flaggerv1.CanaryAnalysis{
- Interval: "1m",
- StepWeight: 100,
+ Interval: "1m",
+ StepWeight: 100,
+ StepWeightPromotion: 50,
  }
  mocks := newDeploymentFixture(cd)
 
@@ -163,7 +164,11 @@ func TestScheduler_DeploymentAnalysisPhases(t *testing.T) {
  mocks.ctrl.advanceCanary("podinfo", "default")
  require.NoError(t, assertPhase(mocks.flaggerClient, "podinfo", flaggerv1.CanaryPhaseProgressing))
 
- // promoting
+ // start promotion
+ mocks.ctrl.advanceCanary("podinfo", "default")
+ require.NoError(t, assertPhase(mocks.flaggerClient, "podinfo", flaggerv1.CanaryPhasePromoting))
+
+ // end promotion
  mocks.ctrl.advanceCanary("podinfo", "default")
  require.NoError(t, assertPhase(mocks.flaggerClient, "podinfo", flaggerv1.CanaryPhasePromoting))