Send traffic to the arm64 pods from one Service

charts/lago-rails/templates/_helpers.tpl

@@ -37,7 +37,7 @@ Common labels
 */}}
 {{- define "lago-rails.labels" -}}
 helm.sh/chart: {{ include "lago-rails.chart" . }}
-{{ include "lago-rails.selectorLabels" . }}
+{{ include "lago-rails.architecture.selectorLabels" . }}
 {{- if .Chart.AppVersion }}
 app.kubernetes.io/version: {{ .Chart.AppVersion | quote }}
 {{- end }}
@@ -73,32 +73,40 @@ amd64 name.
 {{- end }}
 
 {{/*
-Create architecture-specific selector labels. The amd64 result delegates to
-the existing helper so its rendered labels do not change.
+Create architecture-specific selector labels. Each architecture keeps its own
+`app.kubernetes.io/name`, so a Deployment selector matches only its own pods.
+The Deployment selector is immutable, so this helper must not change.
 */}}
 {{- define "lago-rails.architecture.selectorLabels" -}}
 {{- if eq (include "lago-rails.architecture.isArm64" .) "true" -}}
-app.kubernetes.io/name: {{ printf "%s-arm64" .Values.internalArchitectureName | trunc 63 | trimSuffix "-" }}
+app.kubernetes.io/name: {{ printf "%s-arm64" (include "lago-rails.name" .) | trunc 63 | trimSuffix "-" }}
 app.kubernetes.io/instance: {{ .Release.Name }}
 {{- else -}}
 {{- include "lago-rails.selectorLabels" . -}}
 {{- end -}}
 {{- end }}
 
 {{/*
-Create architecture-specific labels. The amd64 result delegates to the
-existing helper so its rendered labels do not change.
+The architecture-independent label that every pod of this workload carries. The
+Service and the PodDisruptionBudget select it, so they reach the pods of all
+architectures.
 */}}
-{{- define "lago-rails.architecture.labels" -}}
-{{- if eq (include "lago-rails.architecture.isArm64" .) "true" -}}
-helm.sh/chart: {{ include "lago-rails.chart" . }}
-{{ include "lago-rails.architecture.selectorLabels" . }}
-{{- if .Chart.AppVersion }}
-app.kubernetes.io/version: {{ .Chart.AppVersion | quote }}
+{{- define "lago-rails.componentLabel" -}}
+app.kubernetes.io/component: {{ include "lago-rails.name" . }}
 {{- end }}
-app.kubernetes.io/managed-by: {{ .Release.Service }}
+
+{{/*
+Selector labels for the Service and the PodDisruptionBudget. arm64 pods have a
+different `app.kubernetes.io/name`, so the selector moves to the `component`
+label when arm64 is enabled. Every pod already carries that label, because the
+chart adds it to all pod templates.
+*/}}
+{{- define "lago-rails.service.selectorLabels" -}}
+{{- if .Values.global.architectures.arm64.enabled -}}
+app.kubernetes.io/instance: {{ .Release.Name }}
+{{ include "lago-rails.componentLabel" . }}
 {{- else -}}
-{{- include "lago-rails.labels" . -}}
+{{- include "lago-rails.selectorLabels" . -}}
 {{- end -}}
 {{- end }}
 

charts/lago-rails/templates/deployment.yaml

@@ -8,7 +8,7 @@ metadata:
     {{- toYaml . | nindent 4 }}
   {{- end }}
   labels:
-    {{- include "lago-rails.architecture.labels" . | nindent 4 }}
+    {{- include "lago-rails.labels" . | nindent 4 }}
 spec:
   {{- if not .Values.autoscaling.enabled }}
   replicas: {{ .Values.replicaCount }}
@@ -23,7 +23,8 @@ spec:
         {{- toYaml . | nindent 8 }}
       {{- end }}
       labels:
-        {{- include "lago-rails.architecture.labels" . | nindent 8 }}
+        {{- include "lago-rails.labels" . | nindent 8 }}
+        {{- include "lago-rails.componentLabel" . | nindent 8 }}
         {{- with .Values.podLabels }}
         {{- toYaml . | nindent 8 }}
         {{- end }}
@@ -480,7 +481,6 @@ spec:
 {{- $_ := set $amd64Values "tolerations" (concat .Values.tolerations $amd64.tolerations) }}
 {{- $amd64Context := dict "Values" $amd64Values "Chart" .Chart "Release" .Release "Capabilities" .Capabilities "Template" .Template "Files" .Files }}
 {{- $architectureFullname := include "lago-rails.fullname" $amd64Context }}
-{{- $architectureName := include "lago-rails.name" $amd64Context }}
 {{- if .Values.global.architectures.amd64.enabled }}
 {{ include "lago-rails.deployment" $amd64Context }}
 {{- end }}
@@ -492,7 +492,6 @@ spec:
 {{- $arm64Values := deepCopy .Values }}
 {{- $_ := set $arm64Values "internalArchitecture" "arm64" }}
 {{- $_ := set $arm64Values "internalArchitectureFullname" $architectureFullname }}
-{{- $_ := set $arm64Values "internalArchitectureName" $architectureName }}
 {{- $_ := set $arm64Values "replicaCount" $arm64.replicaCount }}
 {{- $_ := set $arm64Values "nodeSelector" (mustMergeOverwrite (deepCopy .Values.nodeSelector) $arm64.nodeSelector) }}
 {{- $_ := set $arm64Values "tolerations" (concat .Values.tolerations $arm64.tolerations) }}

charts/lago-rails/templates/hpa.yaml

@@ -4,7 +4,7 @@ kind: HorizontalPodAutoscaler
 metadata:
   name: {{ include "lago-rails.architecture.fullname" . }}
   labels:
-    {{- include "lago-rails.architecture.labels" . | nindent 4 }}
+    {{- include "lago-rails.labels" . | nindent 4 }}
 spec:
   scaleTargetRef:
     apiVersion: apps/v1
@@ -42,7 +42,6 @@ spec:
 {{- $arm64Values := deepCopy .Values }}
 {{- $_ := set $arm64Values "internalArchitecture" "arm64" }}
 {{- $_ := set $arm64Values "internalArchitectureFullname" (include "lago-rails.fullname" .) }}
-{{- $_ := set $arm64Values "internalArchitectureName" (include "lago-rails.name" .) }}
 {{- $_ := set $arm64Values "autoscaling" $arm64.autoscaling }}
 {{- $arm64Context := dict "Values" $arm64Values "Chart" .Chart "Release" .Release "Capabilities" .Capabilities "Template" .Template "Files" .Files }}
 {{ include "lago-rails.hpa" $arm64Context }}

charts/lago-rails/templates/pdb.yaml

@@ -1,10 +1,14 @@
-{{- define "lago-rails.pdb" -}}
+{{/*
+One PodDisruptionBudget for all architectures. The pods of both serve the same
+Service, so one budget applies to them together.
+*/}}
+{{- if .Values.podDisruptionBudget.enabled }}
 apiVersion: policy/v1
 kind: PodDisruptionBudget
 metadata:
-  name: {{ include "lago-rails.architecture.fullname" . }}
+  name: {{ include "lago-rails.fullname" . }}
   labels:
-    {{- include "lago-rails.architecture.labels" . | nindent 4 }}
+    {{- include "lago-rails.labels" . | nindent 4 }}
 spec:
   {{- with .Values.podDisruptionBudget.minAvailable }}
   minAvailable: {{ . }}
@@ -14,21 +18,5 @@ spec:
   {{- end }}
   selector:
     matchLabels:
-      {{- include "lago-rails.architecture.selectorLabels" . | nindent 6 }}
-{{- end }}
-
-{{- if .Values.podDisruptionBudget.enabled }}
-{{- $amd64Values := deepCopy .Values }}
-{{- $amd64Context := dict "Values" $amd64Values "Chart" .Chart "Release" .Release "Capabilities" .Capabilities "Template" .Template "Files" .Files }}
-{{ include "lago-rails.pdb" $amd64Context }}
-{{- $arm64 := .Values.architectures.arm64 }}
-{{- if and .Values.global.architectures.arm64.enabled (or (gt (int $arm64.replicaCount) 0) $arm64.autoscaling.enabled) }}
----
-{{- $arm64Values := deepCopy .Values }}
-{{- $_ := set $arm64Values "internalArchitecture" "arm64" }}
-{{- $_ := set $arm64Values "internalArchitectureFullname" (include "lago-rails.fullname" .) }}
-{{- $_ := set $arm64Values "internalArchitectureName" (include "lago-rails.name" .) }}
-{{- $arm64Context := dict "Values" $arm64Values "Chart" .Chart "Release" .Release "Capabilities" .Capabilities "Template" .Template "Files" .Files }}
-{{ include "lago-rails.pdb" $arm64Context }}
-{{- end }}
+      {{- include "lago-rails.service.selectorLabels" . | nindent 6 }}
 {{- end }}

charts/lago-rails/templates/service.yaml

@@ -1,10 +1,14 @@
-{{- define "lago-rails.service" -}}
+{{/*
+One Service for all architectures. The selector has no
+`app.kubernetes.io/component`, so it matches amd64 pods and arm64 pods.
+*/}}
+{{- if .Values.service.enabled }}
 apiVersion: v1
 kind: Service
 metadata:
-  name: {{ include "lago-rails.architecture.fullname" . }}
+  name: {{ include "lago-rails.fullname" . }}
   labels:
-    {{- include "lago-rails.architecture.labels" . | nindent 4 }}
+    {{- include "lago-rails.labels" . | nindent 4 }}
 spec:
   type: {{ .Values.service.type }}
   ports:
@@ -13,21 +17,5 @@ spec:
       protocol: TCP
       name: http
   selector:
-    {{- include "lago-rails.architecture.selectorLabels" . | nindent 4 }}
-{{- end }}
-
-{{- if .Values.service.enabled }}
-{{- $amd64Values := deepCopy .Values }}
-{{- $amd64Context := dict "Values" $amd64Values "Chart" .Chart "Release" .Release "Capabilities" .Capabilities "Template" .Template "Files" .Files }}
-{{ include "lago-rails.service" $amd64Context }}
-{{- $arm64 := .Values.architectures.arm64 }}
-{{- if and .Values.global.architectures.arm64.enabled (or (gt (int $arm64.replicaCount) 0) $arm64.autoscaling.enabled) }}
----
-{{- $arm64Values := deepCopy .Values }}
-{{- $_ := set $arm64Values "internalArchitecture" "arm64" }}
-{{- $_ := set $arm64Values "internalArchitectureFullname" (include "lago-rails.fullname" .) }}
-{{- $_ := set $arm64Values "internalArchitectureName" (include "lago-rails.name" .) }}
-{{- $arm64Context := dict "Values" $arm64Values "Chart" .Chart "Release" .Release "Capabilities" .Capabilities "Template" .Template "Files" .Files }}
-{{ include "lago-rails.service" $arm64Context }}
-{{- end }}
+    {{- include "lago-rails.service.selectorLabels" . | nindent 4 }}
 {{- end }}

charts/lago/tests/architecture_test.yaml

@@ -2,6 +2,7 @@ suite: Test amd64 and arm64 API and worker deployments
 templates:
   - charts/api/templates/deployment.yaml
   - charts/worker/templates/deployment.yaml
+  - charts/api/templates/service.yaml
 
 set:
   global:
@@ -201,6 +202,59 @@ tests:
       - hasDocuments:
           count: 1
 
+  - it: keeps a separate name in each deployment selector
+    template: charts/api/templates/deployment.yaml
+    asserts:
+      - equal:
+          path: spec.selector.matchLabels
+          value:
+            app.kubernetes.io/name: lago-api
+            app.kubernetes.io/instance: RELEASE-NAME
+        documentIndex: 0
+      - equal:
+          path: spec.selector.matchLabels
+          value:
+            app.kubernetes.io/name: lago-api-arm64
+            app.kubernetes.io/instance: RELEASE-NAME
+        documentIndex: 1
+
+  - it: gives the pods of both architectures the same component label
+    template: charts/api/templates/deployment.yaml
+    asserts:
+      - equal:
+          path: spec.template.metadata.labels["app.kubernetes.io/component"]
+          value: lago-api
+        documentIndex: 0
+      - equal:
+          path: spec.template.metadata.labels["app.kubernetes.io/component"]
+          value: lago-api
+        documentIndex: 1
+
+  - it: renders one API service that selects the component when arm64 is on
+    template: charts/api/templates/service.yaml
+    asserts:
+      - hasDocuments:
+          count: 1
+      - equal:
+          path: spec.selector
+          value:
+            app.kubernetes.io/instance: RELEASE-NAME
+            app.kubernetes.io/component: lago-api
+
+  - it: keeps the original API service selector when arm64 is off
+    template: charts/api/templates/service.yaml
+    set:
+      global:
+        architectures:
+          arm64:
+            enabled: false
+    asserts:
+      - equal:
+          path: spec.selector
+          value:
+            app.kubernetes.io/name: lago-api
+            app.kubernetes.io/instance: RELEASE-NAME
+
   - it: renders an arm64 worker without replicas when KEDA controls it
     template: charts/worker/templates/deployment.yaml
     set: