Use per-component matchLabels selector in pod specs (fix #355)

Signed-off-by: Dr. Jan-Philip Gehrcke <[email protected]>

Author: jgehrcke

deployments/helm/nvidia-dra-driver-gpu/templates/_helpers.tpl

@@ -43,36 +43,47 @@ Create chart name and version as used by the chart label.
 {{- end }}
 
 {{/*
-Common labels
+Standard labels: documented at
+https://helm.sh/docs/chart_best_practices/labels/
+Apply this to all high-level objects (Deployment, DaemonSet, ...).
+Pod template labels are included here to deliver name+instance.
 */}}
 {{- define "nvidia-dra-driver-gpu.labels" -}}
 helm.sh/chart: {{ include "nvidia-dra-driver-gpu.chart" . }}
-{{ include "nvidia-dra-driver-gpu.templateLabels" . }}
-{{- if .Chart.AppVersion }}
 app.kubernetes.io/version: {{ .Chart.AppVersion | quote }}
-{{- end }}
 app.kubernetes.io/managed-by: {{ .Release.Service }}
+{{ include "nvidia-dra-driver-gpu.templateLabels" . }}
 {{- end }}
 
 {{/*
-Template labels
+Apply this to all pod templates (a smaller set of labels compared to
+the set of standard labels above, to not clutter individual pods too
+much). Note that these labels cannot be used to distinguish
+components within this Helm chart.
 */}}
 {{- define "nvidia-dra-driver-gpu.templateLabels" -}}
 app.kubernetes.io/name: {{ include "nvidia-dra-driver-gpu.name" . }}
 app.kubernetes.io/instance: {{ .Release.Name }}
-{{- if .Values.selectorLabelsOverride }}
-{{ toYaml .Values.selectorLabelsOverride }}
-{{- end }}
 {{- end }}
 
 {{/*
-Selector labels
+Selector label: precisely filter for just the pods of the corresponding
+Deployment, DaemonSet, .... That is, this label key/value pair must be
+different per-component (a component name is a required argument). This
+could be many labels, but we want to use just one (with a sufficiently
+unique key).
+
+TOOD: remove the override feature, or make the override work per-component.
 */}}
 {{- define "nvidia-dra-driver-gpu.selectorLabels" -}}
-{{- if .Values.selectorLabelsOverride -}}
-{{ toYaml .Values.selectorLabelsOverride }}
+{{- if and (hasKey . "componentName") (hasKey . "context") -}}
+{{- if .context.Values.selectorLabelsOverride -}}
+{{ toYaml .context.Values.selectorLabelsOverride }}
 {{- else -}}
-{{ include "nvidia-dra-driver-gpu.templateLabels" . }}
+{{ .context.Chart.Name }}-component: {{ .componentName }}
+{{- end }}
+{{- else -}}
+fail "selectorLabels: both arguments are required: context, componentName"
 {{- end }}
 {{- end }}
 

deployments/helm/nvidia-dra-driver-gpu/templates/controller.yaml

@@ -25,7 +25,7 @@ spec:
   replicas: 1
   selector:
     matchLabels:
-      {{- include "nvidia-dra-driver-gpu.selectorLabels" . | nindent 6 }}
+      {{- include "nvidia-dra-driver-gpu.selectorLabels" (dict "context" . "componentName" "controller") | nindent 6 }}
   template:
     metadata:
       {{- with .Values.controller.podAnnotations }}
@@ -34,6 +34,7 @@ spec:
       {{- end }}
       labels:
         {{- include "nvidia-dra-driver-gpu.templateLabels" . | nindent 8 }}
+        {{- include "nvidia-dra-driver-gpu.selectorLabels" (dict "context" . "componentName" "controller") | nindent 8 }}
     spec:
       {{- if .Values.controller.priorityClassName }}
       priorityClassName: {{ .Values.controller.priorityClassName }}

deployments/helm/nvidia-dra-driver-gpu/templates/kubeletplugin.yaml

@@ -24,7 +24,7 @@ metadata:
 spec:
   selector:
     matchLabels:
-      {{- include "nvidia-dra-driver-gpu.selectorLabels" . | nindent 6 }}
+      {{- include "nvidia-dra-driver-gpu.selectorLabels" (dict "context" . "componentName" "kubelet-plugin") | nindent 6 }}
   {{- with .Values.kubeletPlugin.updateStrategy }}
   updateStrategy:
     {{- toYaml . | nindent 4 }}
@@ -37,6 +37,7 @@ spec:
       {{- end }}
       labels:
         {{- include "nvidia-dra-driver-gpu.templateLabels" . | nindent 8 }}
+        {{- include "nvidia-dra-driver-gpu.selectorLabels" (dict "context" . "componentName" "kubelet-plugin") | nindent 8 }}
     spec:
       {{- if .Values.kubeletPlugin.priorityClassName }}
       priorityClassName: {{ .Values.kubeletPlugin.priorityClassName }}