Closes #748. Pad the injector pod durations so they usually complete … (#779)

* Closes #748. Pad the injector pod durations so they usually complete later than the chaos-controller

Author: ptnapoleon

services/chaospod.go

@@ -310,8 +310,11 @@ func (m *chaosPodService) GenerateChaosPodOfDisruption(disruption *chaosv1beta1.
 	// to give time for cleaning
 	activeDeadlineSeconds := int64(disruption.RemainingDuration().Seconds()) + 10
 
+	// It can cause abnormalities in the status of a Disruption if injector pods consider themselves complete in the ~second before the chaos-controller believes the disruption is complete.
+	// To avoid making our termination state machine logic more complicated, we will pad the injector pod duration by two seconds.
+	// See https://github.com/DataDog/chaos-controller/issues/748
 	args = append(args,
-		"--deadline", time.Now().Add(disruption.RemainingDuration()).Format(time.RFC3339))
+		"--deadline", time.Now().Add(chaostypes.InjectorPadDuration).Add(disruption.RemainingDuration()).Format(time.RFC3339))
 
 	chaosPod = corev1.Pod{
 		ObjectMeta: metav1.ObjectMeta{

services/chaospod_test.go

@@ -728,7 +728,7 @@ var _ = Describe("Chaos Pod Service", func() {
 			args.NotInjectedBefore = notInjectedBefore
 
 			expectedArgs = args.CreateCmdArgs(subSpec.GenerateArgs())
-			expectedArgs = append(expectedArgs, "--deadline", time.Now().Add(disruption.RemainingDuration()).Format(time.RFC3339))
+			expectedArgs = append(expectedArgs, "--deadline", time.Now().Add(chaostypes.InjectorPadDuration).Add(disruption.RemainingDuration()).Format(time.RFC3339))
 
 			// Action
 			chaosPods, err = chaosPodService.GenerateChaosPodsOfDisruption(&disruption, DefaultTargetName, DefaultTargetNodeName, targetContainers, DefaultTargetPodIp)

types/types.go

@@ -125,6 +125,9 @@ const (
 	ChaosPodFinalizer   = finalizerPrefix + "/chaos-pod"
 
 	PulsingDisruptionMinimumDuration = 500 * time.Millisecond
+	// InjectorPadDuration is the length of time we extend the injector's duration on top of the disruption's duration,
+	// in order to ensure the manager stops the disruption prior to the injectors dying
+	InjectorPadDuration = 2 * time.Second
 
 	// InjectorCgroupClassID is linked to the TC tree in the injector network disruption.
 	// Also used in the DNS Disruption to allow combined Network + DNS Disruption