feat: HPA support for control-layer and fusillade workloads

README.md

@@ -69,7 +69,12 @@ The following table lists the configurable parameters and their default values.
 
 | Parameter | Description | Default |
 |-----------|-------------|---------|
-| `replicaCount` | Number of replicas | `1` |
+| `replicaCount` | Number of replicas (omitted from the Deployment when `autoscaling.enabled`) | `1` |
+| `autoscaling.enabled` | Render a HorizontalPodAutoscaler for the control-layer deployment | `false` |
+| `autoscaling.minReplicas` | HPA minimum replicas | `1` |
+| `autoscaling.maxReplicas` | HPA maximum replicas | `3` |
+| `autoscaling.metrics` | Raw `autoscaling/v2` metrics list, rendered verbatim | `[]` |
+| `autoscaling.behavior` | Raw `autoscaling/v2` behavior block, rendered verbatim | `{}` |
 | `image.repository` | Container image repository | `ghcr.io/doublewordai/control-layer` |
 | `image.tag` | Container image tag | Chart appVersion |
 | `image.pullPolicy` | Image pull policy | `IfNotPresent` |
@@ -191,16 +196,19 @@ The fusillade daemon handles background batch processing tasks. By default, it r
 | Parameter | Description | Default |
 |-----------|-------------|---------|
 | `fusillade.enabled` | Deploy fusillade as a separate deployment | `false` |
-| `fusillade.replicaCount` | Number of fusillade replicas | `1` |
+| `fusillade.replicaCount` | Number of fusillade replicas (omitted from a Deployment whose effective autoscaling is enabled) | `1` |
+| `fusillade.autoscaling` | HPA defaults for the fusillade daemon and both split roles (`enabled`, `minReplicas`, `maxReplicas`, `metrics`, `behavior`) | `enabled: false` |
 | `fusillade.mode` | Optional daemon mode for the standard fusillade deployment (`both`, `request_only`, `batch_only`); empty uses the application default | `""` |
 | `fusillade.split.enabled` | Render separate request-only and batch-only daemon deployments | `false` |
 | `fusillade.split.request.enabled` | Render the request-only daemon deployment | `true` |
 | `fusillade.split.request.replicaCount` | Number of request daemon replicas | inherits `fusillade.replicaCount` |
+| `fusillade.split.request.autoscaling` | HPA override for the request daemon | merged over `fusillade.autoscaling` |
 | `fusillade.split.request.resources` | CPU/Memory requests/limits for request daemon pods | inherits `fusillade.resources` |
 | `fusillade.split.request.env` | Additional environment variables for request daemon pods | merged after `env` and `fusillade.env` |
 | `fusillade.split.request.database` | Database pool overrides for request daemon pods | merged over `fusillade.database` |
 | `fusillade.split.batch.enabled` | Render the batch-only daemon deployment | `true` |
 | `fusillade.split.batch.replicaCount` | Number of batch daemon replicas | inherits `fusillade.replicaCount` |
+| `fusillade.split.batch.autoscaling` | HPA override for the batch daemon | merged over `fusillade.autoscaling` |
 | `fusillade.split.batch.resources` | CPU/Memory requests/limits for batch daemon pods | inherits `fusillade.resources` |
 | `fusillade.split.batch.env` | Additional environment variables for batch daemon pods | merged after `env` and `fusillade.env` |
 | `fusillade.split.batch.database` | Database pool overrides for batch daemon pods | merged over `fusillade.database` |

templates/deployment.yaml

@@ -28,7 +28,11 @@ metadata:
   labels:
     {{- include "control-layer.labels" . | nindent 4 }}
 spec:
+  {{- /* Argo CD reconciles continuously; a rendered replicas field would revert
+       every HPA scale-up on the next sync, so omit it when the HPA owns the count. */}}
+  {{- if not .Values.autoscaling.enabled }}
   replicas: {{ .Values.replicaCount }}
+  {{- end }}
   {{- if .Values.rollout.enabled }}
   strategy:
     {{- toYaml .Values.rollout.strategy | nindent 4 }}

templates/fusillade/deployment.yaml

@@ -10,14 +10,19 @@
 {{- $database := mergeOverwrite (deepCopy ($fusillade.database | default dict)) (get $config "database" | default dict) -}}
 {{- $podAnnotations := mergeOverwrite (deepCopy ($fusillade.podAnnotations | default dict)) (get $config "podAnnotations" | default dict) -}}
 {{- $podLabels := mergeOverwrite (deepCopy ($fusillade.podLabels | default dict)) (get $config "podLabels" | default dict) -}}
+{{- $autoscaling := mergeOverwrite (deepCopy ($fusillade.autoscaling | default dict)) (get $config "autoscaling" | default dict) -}}
 apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: {{ include "control-layer.fullname" $root }}{{ $suffix }}
   labels:
     {{- include "control-layer.fusillade.labelsFor" (dict "root" $root "component" $component) | nindent 4 }}
 spec:
+  {{- /* Argo CD reconciles continuously; a rendered replicas field would revert
+       every HPA scale-up on the next sync, so omit it when the HPA owns the count. */}}
+  {{- if not $autoscaling.enabled }}
   replicas: {{- if hasKey $config "replicaCount" }} {{ get $config "replicaCount" }}{{- else }} {{ $fusillade.replicaCount }}{{- end }}
+  {{- end }}
   selector:
     matchLabels:
       {{- include "control-layer.fusillade.selectorLabelsFor" (dict "root" $root "component" $component) | nindent 6 }}

templates/fusillade/hpa.yaml

@@ -0,0 +1,58 @@
+{{- /*
+One HorizontalPodAutoscaler per fusillade workload whose effective autoscaling
+is enabled. Iterates the same workloads as fusillade/deployment.yaml (single
+mode: -fusillade; split mode: -fusillade-request / -fusillade-batch). Effective
+config = fusillade.autoscaling overlaid with the per-role autoscaling block.
+*/}}
+{{- define "control-layer.fusillade.hpa" -}}
+{{- $root := .root -}}
+{{- $fusillade := $root.Values.fusillade -}}
+{{- $config := .config | default dict -}}
+{{- $component := .component -}}
+{{- $suffix := .suffix -}}
+{{- $autoscaling := mergeOverwrite (deepCopy ($fusillade.autoscaling | default dict)) (get $config "autoscaling" | default dict) -}}
+{{- if $autoscaling.enabled }}
+---
+apiVersion: autoscaling/v2
+kind: HorizontalPodAutoscaler
+metadata:
+  name: {{ include "control-layer.fullname" $root }}{{ $suffix }}
+  labels:
+    {{- include "control-layer.fusillade.labelsFor" (dict "root" $root "component" $component) | nindent 4 }}
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: {{ include "control-layer.fullname" $root }}{{ $suffix }}
+  minReplicas: {{ $autoscaling.minReplicas }}
+  maxReplicas: {{ $autoscaling.maxReplicas }}
+  {{- with $autoscaling.metrics }}
+  metrics:
+    {{- toYaml . | nindent 4 }}
+  {{- end }}
+  {{- with $autoscaling.behavior }}
+  behavior:
+    {{- toYaml . | nindent 4 }}
+  {{- end }}
+{{- end }}
+{{- end -}}
+
+{{- if .Values.fusillade.enabled }}
+{{- $split := .Values.fusillade.split | default dict -}}
+{{- if $split.enabled }}
+{{- $request := $split.request | default dict -}}
+{{- $batch := $split.batch | default dict -}}
+{{- $requestEnabled := true -}}
+{{- $batchEnabled := true -}}
+{{- if hasKey $request "enabled" }}{{- $requestEnabled = $request.enabled -}}{{- end -}}
+{{- if hasKey $batch "enabled" }}{{- $batchEnabled = $batch.enabled -}}{{- end -}}
+{{- if $requestEnabled }}
+{{- include "control-layer.fusillade.hpa" (dict "root" . "suffix" "-fusillade-request" "component" "fusillade-request" "config" $request) }}
+{{- end }}
+{{- if $batchEnabled }}
+{{- include "control-layer.fusillade.hpa" (dict "root" . "suffix" "-fusillade-batch" "component" "fusillade-batch" "config" $batch) }}
+{{- end }}
+{{- else }}
+{{- include "control-layer.fusillade.hpa" (dict "root" . "suffix" "-fusillade" "component" "fusillade" "config" dict) }}
+{{- end }}
+{{- end }}

templates/hpa.yaml

@@ -0,0 +1,23 @@
+{{- if .Values.autoscaling.enabled }}
+apiVersion: autoscaling/v2
+kind: HorizontalPodAutoscaler
+metadata:
+  name: {{ include "control-layer.fullname" . }}
+  labels:
+    {{- include "control-layer.labels" . | nindent 4 }}
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: {{ include "control-layer.fullname" . }}
+  minReplicas: {{ .Values.autoscaling.minReplicas }}
+  maxReplicas: {{ .Values.autoscaling.maxReplicas }}
+  {{- with .Values.autoscaling.metrics }}
+  metrics:
+    {{- toYaml . | nindent 4 }}
+  {{- end }}
+  {{- with .Values.autoscaling.behavior }}
+  behavior:
+    {{- toYaml . | nindent 4 }}
+  {{- end }}
+{{- end }}

tests/control_layer_deployment_test.yaml

@@ -220,3 +220,19 @@ tests:
     asserts:
       - failedTemplate:
           errorMessage: rollout.connectionDrainTimeoutSeconds must be 3600 to match the control-layer request timeout
+
+  - it: should render replicas by default (no autoscaling)
+    template: deployment.yaml
+    asserts:
+      - equal:
+          path: spec.replicas
+          value: 1
+
+  - it: should omit replicas when autoscaling is enabled
+    template: deployment.yaml
+    set:
+      autoscaling.enabled: true
+    asserts:
+      - isNull:
+          path: spec.replicas
+

tests/fusillade_deployment_test.yaml

@@ -371,3 +371,20 @@ tests:
           content:
             name: DWCTL_BACKGROUND_SERVICES__BATCH_DAEMON__MODE
             value: "request_only"
+
+  - it: should keep replicas in split mode by default
+    template: fusillade/deployment.yaml
+    set:
+      fusillade:
+        enabled: true
+        split:
+          enabled: true
+    asserts:
+      - equal:
+          path: spec.replicas
+          value: 1
+        documentIndex: 0
+      - equal:
+          path: spec.replicas
+          value: 1
+        documentIndex: 1