add autoscaler for queriers (grafana#190)

Signed-off-by: Tom Hayward <thayward@infoblox.com>

Author: kd7lxl

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## master / unreleased
 
+* [FEATURE] Add autoscaler for queriers #190
 * [FEATURE] Add autoscaler for distributors #189
 * [FEATURE] Add autoscaler for ingesters #182
 * [ENHANCEMENT] Define namespace in templates #184

README.md

@@ -632,6 +632,12 @@ Kubernetes: `^1.19.0-0`
 | querier.affinity.podAntiAffinity.preferredDuringSchedulingIgnoredDuringExecution[0].podAffinityTerm.topologyKey | string | `"kubernetes.io/hostname"` |  |
 | querier.affinity.podAntiAffinity.preferredDuringSchedulingIgnoredDuringExecution[0].weight | int | `100` |  |
 | querier.annotations | object | `{}` |  |
+| querier.autoscaling.behavior | object | `{}` | Ref: https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/#support-for-configurable-scaling-behavior |
+| querier.autoscaling.enabled | bool | `false` | Creates a HorizontalPodAutoscaler for the querier pods. |
+| querier.autoscaling.maxReplicas | int | `30` |  |
+| querier.autoscaling.minReplicas | int | `2` |  |
+| querier.autoscaling.targetCPUUtilizationPercentage | int | `80` |  |
+| querier.autoscaling.targetMemoryUtilizationPercentage | int | `0` |  |
 | querier.containerSecurityContext.enabled | bool | `true` |  |
 | querier.containerSecurityContext.readOnlyRootFilesystem | bool | `true` |  |
 | querier.env | list | `[]` |  |

ci/test-values.yaml

@@ -67,5 +67,8 @@ distributor:
   autoscaling:
     enabled: true
     minReplicas: 1
+querier:
+  autoscaling:
+    enabled: true
 nginx:
   replicas: 1

templates/querier/querier-dep.yaml

@@ -8,7 +8,9 @@ metadata:
   annotations:
     {{- toYaml .Values.querier.annotations | nindent 4 }}
 spec:
+  {{- if not .Values.querier.autoscaling.enabled }}
   replicas: {{ .Values.querier.replicas }}
+  {{- end }}
   selector:
     matchLabels:
       {{- include "cortex.querierSelectorLabels" . | nindent 6 }}

templates/querier/querier-hpa.yaml

@@ -0,0 +1,39 @@
+{{- with .Values.querier.autoscaling -}}
+{{- if .enabled }}
+apiVersion: autoscaling/v2beta2
+kind: HorizontalPodAutoscaler
+metadata:
+  name: {{ include "cortex.querierFullname" $ }}
+  namespace: {{ $.Release.Namespace }}
+  labels:
+    {{- include "cortex.querierLabels" $ | nindent 4 }}
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: {{ include "cortex.querierFullname" $ }}
+  minReplicas: {{ .minReplicas }}
+  maxReplicas: {{ .maxReplicas }}
+  metrics:
+  {{- with .targetCPUUtilizationPercentage }}
+    - type: Resource
+      resource:
+        name: cpu
+        target:
+          type: Utilization
+          averageUtilization: {{ . }}
+  {{- end }}
+  {{- with .targetMemoryUtilizationPercentage }}
+    - type: Resource
+      resource:
+        name: memory
+        target:
+          type: Utilization
+          averageUtilization: {{ . }}
+  {{- end }}
+  {{- with .behavior }}
+  behavior:
+    {{- toYaml . | nindent 4 }}
+  {{- end }}
+{{- end }}
+{{- end }}

values.yaml

@@ -819,6 +819,17 @@ querier:
             topologyKey: 'kubernetes.io/hostname'
 
   annotations: {}
+
+  autoscaling:
+    # -- Creates a HorizontalPodAutoscaler for the querier pods.
+    enabled: false
+    minReplicas: 2
+    maxReplicas: 30
+    targetCPUUtilizationPercentage: 80
+    targetMemoryUtilizationPercentage: 0  # 80
+    # -- Ref: https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/#support-for-configurable-scaling-behavior
+    behavior: {}
+
   persistence:
     subPath: