[stable/coredns] Chart updates (helm#23284)

* [stable/coredns] Add ability to customize, preStopHook, podAnnotations, rolllingUpdate specs, terminationGracePeriodSeconds to coredns. Add optional HPA definition as a alternative to proportional autoscaler. Signed-off-by: Adam Hamsik <[email protected]> * Fix helm lint run Signed-off-by: Adam Hamsik <[email protected]> * Update documentation, add custom labels to HPA. Signed-off-by: Adam Hamsik <[email protected]> * Fix rollingupdate variable name. Signed-off-by: Adam Hamsik <[email protected]> Co-authored-by: Martin Dojcak <[email protected]>
davidsmf · Jul 28, 2020 · 9fcfb8b · 9fcfb8b
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diff --git a/stable/coredns/Chart.yaml b/stable/coredns/Chart.yaml
@@ -1,6 +1,6 @@
 apiVersion: v1
 name: coredns
-version: 1.13.1
+version: 1.13.2
 appVersion: 1.7.0
 description: CoreDNS is a DNS server that chains plugins and provides Kubernetes DNS Services
 keywords:

diff --git a/stable/coredns/README.md b/stable/coredns/README.md
@@ -79,7 +79,16 @@ The command removes all the Kubernetes components associated with the chart and
 | `extraVolumeMounts`                     | Optional array of volumes to mount inside the CoreDNS container                       | []                                                          |
 | `extraSecrets`                          | Optional array of secrets to mount inside the CoreDNS container                       | []                                                          |
 | `customLabels`                          | Optional labels for Deployment(s), Pod, Service, ServiceMonitor objects               | {}                                                          |
+| `rollingUpdate.maxUnavailable`          | Maximum number of unavailable replicas during rolling update                          | `1`                                                         |
+| `rollingUpdate.maxSurge`                | Maximum number of pods created above desired number of pods                           | `25%`                                                       |
 | `podDisruptionBudget`                   | Optional PodDisruptionBudget                                                          | {}                                                          |
+| `podAnnotations`                        | Optional Pod only Annotations                                                         | {}                                                          |
+| `terminationGracePeriodSeconds`         | Optional duration in seconds the pod needs to terminate gracefully.                   | 30                                                          |
+| `preStopSleep`                          | Definition of Kubernetes preStop hook executed before Pod termination                 | {}                                                          |
+| `hpa.enabled`                           | Enable Hpa autoscaler instead of proportional one                                     | `false`                                                     |
+| `hpa.minReplicas`                       | Hpa minimum number of CoreDNS replicas                                                | `1`                                                         |
+| `hpa.maxReplicas`                       | Hpa maximum number of CoreDNS replicas                                                | `2`                                                         |
+| `hpa.metrics`                           | Metrics definitions used by Hpa to scale up and down                                  | {}                                                          |
 | `autoscaler.enabled`                    | Optionally enabled a cluster-proportional-autoscaler for CoreDNS                      | `false`                                                     |
 | `autoscaler.coresPerReplica`            | Number of cores in the cluster per CoreDNS replica                                    | `256`                                                       |
 | `autoscaler.nodesPerReplica`            | Number of nodes in the cluster per CoreDNS replica                                    | `16`                                                        |
@@ -144,3 +153,7 @@ This also creates a ServiceAccount, ClusterRole, and ClusterRoleBinding for
 the autoscaler deployment.
 
 `replicaCount` is ignored if this is enabled.
+
+By setting `hpa.enabled = true` a [Horizontal Pod Autoscaler](https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/)
+is enabled for Coredns deployment. This can scale number of replicas based on meitrics
+like CpuUtilization, MemoryUtilization or Custom ones.
diff --git a/stable/coredns/templates/deployment-autoscaler.yaml b/stable/coredns/templates/deployment-autoscaler.yaml
@@ -1,4 +1,4 @@
-{{- if .Values.autoscaler.enabled }}
+{{- if and (.Values.autoscaler.enabled) (not .Values.hpa.enabled) }}
 ---
 apiVersion: apps/v1
 kind: Deployment

diff --git a/stable/coredns/templates/deployment.yaml b/stable/coredns/templates/deployment.yaml
@@ -22,8 +22,8 @@ spec:
   strategy:
     type: RollingUpdate
     rollingUpdate:
-      maxUnavailable: 1
-      maxSurge: 10%
+      maxUnavailable: {{ .Values.rollingUpdate.maxUnavailable }}
+      maxSurge: {{ .Values.rollingUpdate.maxSurge }}
   selector:
     matchLabels:
       app.kubernetes.io/instance: {{ .Release.Name | quote }}
@@ -39,16 +39,22 @@ spec:
         {{- end }}
         app.kubernetes.io/name: {{ template "coredns.name" . }}
         app.kubernetes.io/instance: {{ .Release.Name | quote }}
-{{- if .Values.customLabels }}
-{{ toYaml .Values.customLabels | indent 8 }}
-{{- end }}
+        {{- if .Values.customLabels }}
+        {{ toYaml .Values.customLabels }}
+        {{- end }}
       annotations:
         checksum/config: {{ include (print $.Template.BasePath "/configmap.yaml") . | sha256sum }}
         {{- if .Values.isClusterService }}
         scheduler.alpha.kubernetes.io/critical-pod: ''
         scheduler.alpha.kubernetes.io/tolerations: '[{"key":"CriticalAddonsOnly", "operator":"Exists"}]'
         {{- end }}
+        {{- if .Values.podAnnotations }}
+        {{ toYaml .Values.podAnnotations }}
+        {{- end }}
     spec:
+      {{- if .Values.terminationGracePeriodSeconds }}
+      terminationGracePeriodSeconds: {{ .Values.terminationGracePeriodSeconds }}
+      {{- end }}
       serviceAccountName: {{ template "coredns.serviceAccountName" . }}
       {{- if .Values.priorityClassName }}
       priorityClassName: {{ .Values.priorityClassName | quote }}
@@ -106,6 +112,12 @@ spec:
           timeoutSeconds: 5
           successThreshold: 1
           failureThreshold: 5
+        {{- if .Values.preStopSleep }}
+        lifecycle:
+          preStop:
+            exec:
+              command: ["/usr/bin/sleep", "{{ .Values.preStopSleep }}"]
+        {{- end }}
       volumes:
         - name: config-volume
           configMap:

diff --git a/stable/coredns/templates/hpa.yaml b/stable/coredns/templates/hpa.yaml
@@ -0,0 +1,29 @@
+{{- if and (.Values.hpa.enabled) (not .Values.autoscaler.enabled) }}
+---
+apiVersion: autoscaling/v2beta1
+kind: HorizontalPodAutoscaler
+metadata:
+  name: {{ template "coredns.fullname" . }}
+  labels:
+    app.kubernetes.io/managed-by: {{ .Release.Service | quote }}
+    app.kubernetes.io/instance: {{ .Release.Name | quote }}
+    helm.sh/chart: "{{ .Chart.Name }}-{{ .Chart.Version | replace "+" "_" }}"
+    {{- if .Values.isClusterService }}
+    k8s-app: {{ .Chart.Name | quote }}
+    kubernetes.io/cluster-service: "true"
+    kubernetes.io/name: "CoreDNS"
+    {{- end }}
+    app.kubernetes.io/name: {{ template "coredns.name" . }}
+{{- if .Values.customLabels }}
+{{ toYaml .Values.customLabels | indent 4 }}
+{{- end }}
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: {{ template "coredns.fullname" . }}
+  minReplicas: {{ .Values.hpa.minReplicas }}
+  maxReplicas: {{ .Values.hpa.maxReplicas }}
+  metrics:
+{{ toYaml .Values.hpa.metrics | indent 4 }}
+{{- end }}
diff --git a/stable/coredns/values.yaml b/stable/coredns/values.yaml
@@ -17,6 +17,34 @@ resources:
     cpu: 100m
     memory: 128Mi
 
+## Create HorizontalPodAutoscaler object.
+##
+# autoscaling:
+#   minReplicas: 1
+#   maxReplicas: 10
+#   metrics:
+#   - type: Resource
+#     resource:
+#       name: cpu
+#       targetAverageUtilization: 60
+#   - type: Resource
+#     resource:
+#       name: memory
+#       targetAverageUtilization: 60
+
+rollingUpdate:
+  maxUnavailable: 1
+  maxSurge: 25%
+
+# Under heavy load it takes more that standard time to remove Pod endpoint from a cluster.
+# This will delay termination of our pod by `preStopSleep`. To make sure kube-proxy has
+# enough time to catch up.
+# preStopSleep: 5
+terminationGracePeriodSeconds: 30
+
+podAnnotations: {}
+#  cluster-autoscaler.kubernetes.io/safe-to-evict: "false"
+
 serviceType: "ClusterIP"
 
 prometheus:
@@ -165,6 +193,14 @@ extraSecrets: []
 # Custom labels to apply to Deployment, Pod, Service, ServiceMonitor. Including autoscaler if enabled.
 customLabels: {}
 
+## Alternative configuration for HPA deployment if wanted
+#
+hpa:
+  enabled: false
+  minReplicas: 1
+  maxReplicas: 2
+  metrics: {}
+
 ## Configue a cluster-proportional-autoscaler for coredns
 # See https://github.com/kubernetes-incubator/cluster-proportional-autoscaler
 autoscaler: