Added support for autoscaling based on custom metrics

nano-byte · Jul 3, 2022 · 9a5a7af · 9a5a7af
1 parent da874c3
commit 9a5a7af
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Showing 5 changed files with 75 additions and 7 deletions.
diff --git a/charts/generic-service/README.md b/charts/generic-service/README.md
@@ -67,7 +67,11 @@ app:
 | `replicas`                        | `1`                         | The number of instances of the service to run (set at least `2` for Pod Disruption Budget)               |
 | `autoscaling.enabled`             | `false`                     | Enables automatic starting of additional instances based on CPU load                                     |
 | `autoscaling.maxReplicas`         | `3`                         | The maximum number of instances to run (must be larger than `replicas`)                                  |
-| `autoscaling.targetCpu`           | `50`                        | The desired average CPU load in percent                                                                  |
+| `autoscaling.metric.type`         | `Resource`                  | The type of metric to use for scaling (`Resource`, `Pods`, `Object` or `External`)                       |
+| `autoscaling.metric.name`         | `cpu`                       | The name of the metric to use for scaling                                                                |
+| `autoscaling.metric.object`       | req. if `type` = `Object`   | Reference to the Kubernetes object the metric describes                                                  |
+| `autoscaling.metric.selector`     | `{}`                        | Labels for selecting the metric as a key-value map                                                       |
+| `autoscaling.targetValue`         | `80`                        | The desired value of the metric to achieve through scaling (e.g., CPU utilization in percent)            |
 | `autoscaling.behavior`            | `{}`                        | Scaling behavior configuration (see `HorizontalPodAutoscalerBehavior`)                                   |
 | `nodeSelector`                    | `{}`                        | Node labels required for scheduling this service, also used as tolerations                               |
 | `persistence.enabled`             | `false`                     | Enables persistent storage for the service                                                               |

diff --git a/charts/generic-service/ci/autoscaling-external-values.yaml b/charts/generic-service/ci/autoscaling-external-values.yaml
@@ -0,0 +1,13 @@
+# Autoscaling external metric test
+
+image:
+  repository: jwilder/whoami
+  tag: latest
+
+autoscaling:
+  enabled: true
+  metric:
+    type: External
+    name: some_metric
+    selector:
+      key: value
diff --git a/charts/generic-service/templates/autoscaler.yaml b/charts/generic-service/templates/autoscaler.yaml
@@ -20,11 +20,26 @@ spec:
   maxReplicas: {{ .Values.autoscaling.maxReplicas }}
   behavior: {{ .Values.autoscaling.behavior | toYaml | nindent 4 }}
   metrics:
-    - type: Resource
+    - type: {{ .Values.autoscaling.metric.type }}
+      {{- if eq .Values.autoscaling.metric.type "Resource" }}
       resource:
-        name: cpu
+        name: {{ .Values.autoscaling.metric.name }}
         target:
           type: Utilization
-          averageUtilization: {{ .Values.autoscaling.targetCpu }}
+          averageUtilization: {{ .Values.autoscaling.targetCpu | default .Values.autoscaling.targetValue }}
+      {{- else }}
+      {{ .Values.autoscaling.metric.type | lower }}:
+        metric:
+          name: {{ .Values.autoscaling.metric.name }}
+          {{- if eq .Values.autoscaling.metric.type "Object" }}
+          describedObject: {{ .Values.autoscaling.metric.object | required "autoscaling.metric.object required when autoscaling.metric.type is Object" | toYaml | nindent 10 }}
+          {{- else if eq .Values.autoscaling.metric.type "External" }}
+          selector:
+            matchLabels: {{ .Values.autoscaling.metric.selector | toYaml | nindent 14 }}
+          {{- end }}
+        target:
+          type: Value
+          value: {{ .Values.autoscaling.targetValue }}
+      {{- end }}
 
 {{- end }}
diff --git a/charts/generic-service/values.schema.json b/charts/generic-service/values.schema.json
@@ -253,10 +253,41 @@
           "default": 3,
           "description": "The maximum number of instances to run (must be larger than replicas)"
         },
-        "targetCpu": {
+        "metric": {
+          "type": "object",
+          "properties": {
+            "type": {
+              "type": "string",
+              "enum": ["Resource", "Pods", "Object", "External"],
+              "default": "Resource",
+              "description": "The type of metric to use for scaling"
+            },
+            "name": {
+              "type": "string",
+              "default": "cpu",
+              "description": "The name of the metric to use for scaling"
+            },
+            "object": {
+              "type": ["null", "object"],
+              "properties": {
+                "apiVersion": {"type": "string"},
+                "kind": {"type": "string"},
+                "name": {"type": "string"}
+              },
+              "required": ["apiVersion", "kind", "name"],
+              "description": "Reference to the Kubernetes object the metric describes (required if type = Object)"
+            },
+            "selector": {
+              "type": "object",
+              "additionalProperties": {"type": "string"},
+              "description": "Labels for selecting the metric"
+            }
+          }
+        },
+        "targetValue": {
           "type": "integer",
           "default": 80,
-          "description": "The desired average CPU load in percent"
+          "description": "The desired value of the metric to achieve through scaling (e.g., CPU utilization in percent)"
         },
         "behavior": {
           "type": "object",

diff --git a/charts/generic-service/values.yaml b/charts/generic-service/values.yaml
@@ -61,7 +61,12 @@ replicas: 1
 autoscaling:
   enabled: false
   maxReplicas: 3
-  targetCpu: 80
+  metric:
+    type: Resource
+    name: cpu
+    object:
+    selector: {}
+  targetValue: 80
   behavior: {}
 
 nodeSelector: {}