feat: add a buffer period for ReplicaSet health evaluation

pkg/health/health_replicaset.go

@@ -11,6 +11,10 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 )
 
+// duration after the creation of a replica set
+// within which we never deem the it to be unhealthy.
+const replicaSetBufferPeriod = time.Minute * 10
+
 func getReplicaSetHealth(obj *unstructured.Unstructured) (*HealthStatus, error) {
 	gvk := obj.GroupVersionKind()
 	switch gvk {
@@ -27,6 +31,8 @@ func getReplicaSetHealth(obj *unstructured.Unstructured) (*HealthStatus, error)
 }
 
 func getAppsv1ReplicaSetHealth(replicaSet *appsv1.ReplicaSet) (*HealthStatus, error) {
+	isWithinBufferPeriod := replicaSet.CreationTimestamp.Add(replicaSetBufferPeriod).After(time.Now())
+
 	var containersWaitingForReadiness []string
 	for _, container := range replicaSet.Spec.Template.Spec.Containers {
 		if container.ReadinessProbe != nil && container.ReadinessProbe.InitialDelaySeconds > 0 {
@@ -62,6 +68,11 @@ func getAppsv1ReplicaSetHealth(replicaSet *appsv1.ReplicaSet) (*HealthStatus, er
 		health = HealthUnhealthy
 	}
 
+	if (health == HealthUnhealthy || health == HealthWarning) && isWithinBufferPeriod {
+		// within the buffer period, we don't mark a ReplicaSet as unhealthy
+		health = HealthUnknown
+	}
+
 	if replicaSet.Generation == replicaSet.Status.ObservedGeneration && replicaSet.Status.ReadyReplicas == *replicaSet.Spec.Replicas {
 		return &HealthStatus{
 			Health: health,
@@ -84,7 +95,6 @@ func getAppsv1ReplicaSetHealth(replicaSet *appsv1.ReplicaSet) (*HealthStatus, er
 			Health:  health,
 			Status:  HealthStatusScalingUp,
 			Message: fmt.Sprintf("%d of %d pods ready", replicaSet.Status.ReadyReplicas, *replicaSet.Spec.Replicas),
-			Ready:   true,
 		}, nil
 	}
 
@@ -93,7 +103,6 @@ func getAppsv1ReplicaSetHealth(replicaSet *appsv1.ReplicaSet) (*HealthStatus, er
 			Health:  health,
 			Status:  HealthStatusScalingDown,
 			Message: fmt.Sprintf("%d pods terminating", replicaSet.Status.ReadyReplicas-*replicaSet.Spec.Replicas),
-			Ready:   true,
 		}, nil
 	}
 

pkg/health/health_test.go

@@ -163,6 +163,17 @@ func TestHPA(t *testing.T) {
 	assertAppHealth(t, "./testdata/hpa-v1-progressing-with-no-annotations.yaml", health.HealthStatusProgressing, health.HealthHealthy, false)
 }
 
+func TestReplicaSet(t *testing.T) {
+	assertAppHealthWithOverwrite(t, "./testdata/replicaset-ittools.yml", map[string]string{
+		"2024-08-03T06:06:18Z": time.Now().Add(-time.Minute * 2).UTC().Format("2006-01-02T15:04:05Z"),
+	}, health.HealthStatusRunning, health.HealthHealthy, true)
+
+	assertAppHealthWithOverwrite(t, "./testdata/replicaset-unhealthy-pods.yaml", map[string]string{
+		"2024-10-21T11:20:19Z": time.Now().Add(-time.Minute * 2).UTC().Format("2006-01-02T15:04:05Z"),
+	}, health.HealthStatusScalingUp, health.HealthUnknown, false)
+
+}
+
 func TestPod(t *testing.T) {
 	assertAppHealth(t, "./testdata/terminating-stuck.yaml", "TerminatingStalled", health.HealthUnhealthy, false)
 	assertAppHealth(t, "./testdata/terminating-namespace.yaml", "TerminatingStalled", health.HealthUnhealthy, false)

pkg/health/testdata/replicaset-ittools.yml

@@ -0,0 +1,70 @@
+apiVersion: apps/v1
+kind: ReplicaSet
+metadata:
+  annotations:
+    deployment.kubernetes.io/desired-replicas: "1"
+    deployment.kubernetes.io/max-replicas: "1"
+    deployment.kubernetes.io/revision: "2"
+    meta.helm.sh/release-name: ittools
+    meta.helm.sh/release-namespace: default
+  creationTimestamp: "2024-08-03T06:06:18Z"
+  generation: 52
+  labels:
+    app.kubernetes.io/component: main
+    app.kubernetes.io/instance: ittools
+    app.kubernetes.io/name: ittools
+    pod-template-hash: 5fbf458f49
+  name: ittools-5fbf458f49
+  namespace: default
+  ownerReferences:
+  - apiVersion: apps/v1
+    blockOwnerDeletion: true
+    controller: true
+    kind: Deployment
+    name: ittools
+    uid: d2beccff-8da9-42e8-8459-e7ff938b2ffd
+  resourceVersion: "96413911"
+  uid: c044b250-2445-4813-b00f-22b696c5fcf2
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app.kubernetes.io/component: main
+      app.kubernetes.io/instance: ittools
+      app.kubernetes.io/name: ittools
+      pod-template-hash: 5fbf458f49
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/component: main
+        app.kubernetes.io/instance: ittools
+        app.kubernetes.io/name: ittools
+        pod-template-hash: 5fbf458f49
+    spec:
+      automountServiceAccountToken: true
+      containers:
+      - image: corentinth/it-tools:latest
+        imagePullPolicy: Always
+        name: it-tools
+        resources:
+          limits:
+            memory: 50Mi
+          requests:
+            cpu: 25m
+            memory: 10Mi
+        terminationMessagePath: /dev/termination-log
+        terminationMessagePolicy: File
+      dnsPolicy: ClusterFirst
+      enableServiceLinks: false
+      restartPolicy: Always
+      schedulerName: default-scheduler
+      securityContext: {}
+      serviceAccount: default
+      serviceAccountName: default
+      terminationGracePeriodSeconds: 30
+status:
+  availableReplicas: 1
+  fullyLabeledReplicas: 1
+  observedGeneration: 52
+  readyReplicas: 1
+  replicas: 1

pkg/health/testdata/replicaset-unhealthy-pods.yaml

@@ -0,0 +1,53 @@
+apiVersion: apps/v1
+kind: ReplicaSet
+metadata:
+  uid: f6579017-448f-425a-9645-ea3c93700948
+  name: failing-deployment-866585899d
+  labels:
+    app: failing-app
+    pod-template-hash: 866585899d
+  namespace: default
+  annotations:
+    deployment.kubernetes.io/revision: "1"
+    deployment.kubernetes.io/max-replicas: "2"
+    deployment.kubernetes.io/desired-replicas: "1"
+  ownerReferences:
+    - uid: 1ab20b2b-e2c8-4e85-b7b6-5709ba594c0d
+      kind: Deployment
+      name: failing-deployment
+      apiVersion: apps/v1
+      controller: true
+      blockOwnerDeletion: true
+  creationTimestamp: 2024-10-21T11:20:19Z
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: failing-app
+      pod-template-hash: 866585899d
+  template:
+    spec:
+      dnsPolicy: ClusterFirst
+      containers:
+        - args:
+            - -c
+            - sleep 5 && exit 1
+          name: failing-container
+          image: busybox
+          command:
+            - /bin/sh
+          resources: {}
+          imagePullPolicy: Always
+          terminationMessagePath: /dev/termination-log
+          terminationMessagePolicy: File
+      restartPolicy: Always
+      schedulerName: default-scheduler
+      securityContext: {}
+      terminationGracePeriodSeconds: 30
+    metadata:
+      labels:
+        app: failing-app
+        pod-template-hash: 866585899d
+status:
+  replicas: 1
+  fullyLabeledReplicas: 1