feat(helm): support custom vm.args via RELEASE_VM_ARGS

helm/templates/deployment.yaml

@@ -19,6 +19,9 @@ spec:
     metadata:
       annotations:
         checksum/config: {{ include (print $.Template.BasePath "/configmap.yaml") . | sha256sum }}
+        {{- if .Values.vmArgs }}
+        checksum/vm-args: {{ include (print $.Template.BasePath "/vm-args-configmap.yaml") . | sha256sum }}
+        {{- end }}
         {{- with .Values.podAnnotations }}
         {{- toYaml . | nindent 8 }}
         {{- end }}
@@ -75,6 +78,10 @@ spec:
             - name: LOGFLARE_TLS_KEY_PATH
               value: {{ printf "%s/cert.key" $mount | quote }}
             {{- end }}
+            {{- if .Values.vmArgs }}
+            - name: RELEASE_VM_ARGS
+              value: /etc/logflare/vm.args
+            {{- end }}
           envFrom:
             - configMapRef:
                 name: {{ include "logflare.fullname" . }}
@@ -98,8 +105,14 @@ spec:
           resources:
             {{- toYaml . | nindent 12 }}
           {{- end }}
-          {{- if or .Values.logflare.certFilesSecret .Values.volumeMounts }}
+          {{- if or .Values.vmArgs .Values.logflare.certFilesSecret .Values.volumeMounts }}
           volumeMounts:
+            {{- if .Values.vmArgs }}
+            - name: vm-args
+              mountPath: /etc/logflare/vm.args
+              subPath: vm.args
+              readOnly: true
+            {{- end }}
             {{- if .Values.logflare.certFilesSecret }}
             - name: cert-files
               mountPath: {{ .Values.logflare.certFilesMountPath }}
@@ -109,8 +122,13 @@ spec:
             {{- toYaml . | nindent 12 }}
             {{- end }}
           {{- end }}
-      {{- if or .Values.logflare.certFilesSecret .Values.volumes }}
+      {{- if or .Values.vmArgs .Values.logflare.certFilesSecret .Values.volumes }}
       volumes:
+        {{- if .Values.vmArgs }}
+        - name: vm-args
+          configMap:
+            name: {{ include "logflare.fullname" . }}-vm-args
+        {{- end }}
         {{- if .Values.logflare.certFilesSecret }}
         - name: cert-files
           secret:

helm/templates/vm-args-configmap.yaml

@@ -0,0 +1,11 @@
+{{- if .Values.vmArgs }}
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: {{ include "logflare.fullname" . }}-vm-args
+  labels:
+    {{- include "logflare.labels" . | nindent 4 }}
+data:
+  vm.args: |
+    {{- .Values.vmArgs | nindent 4 }}
+{{- end }}

helm/values.yaml

@@ -88,6 +88,23 @@ logflare:
     postgres:
       schema: "public" # POSTGRES_BACKEND_SCHEMA; url (POSTGRES_BACKEND_URL) comes from a Secret in logflare.secretRefs
 
+# Erlang VM flags. When set, rendered into a ConfigMap, mounted at
+# /etc/logflare/vm.args, and pointed at via RELEASE_VM_ARGS (overriding the
+# image's baked-in vm.args). Set to "" to use the image default instead.
+#
+# `+Q` caps the BEAM's preallocated port table and is effectively REQUIRED on
+# Kubernetes: containerd commonly runs pods with nofile=infinity, and without
+# +Q the VM sizes the table from that limit — ~2GB RSS at boot. Keep +Q set.
+vmArgs: |
+  +Q 1048576
+  +sbwt none
+  +sbwtdcpu none
+  +sbwtdio none
+  +swt very_low
+  +P 8000000
+  -kernel prevent_overlapping_partitions false
+  -kernel net_ticktime 45
+
 # This is for the secrets for pulling an image from a private repository more information can be found here: https://kubernetes.io/docs/tasks/configure-pod-container/pull-image-private-registry/
 imagePullSecrets: []
 # This is to override the chart name.

helm/vmargs_test.yaml

@@ -0,0 +1,54 @@
+suite: test vm.args wiring
+templates:
+  - vm-args-configmap.yaml
+  - deployment.yaml
+tests:
+  - it: renders the vm.args ConfigMap with +Q by default
+    template: vm-args-configmap.yaml
+    asserts:
+      - isKind:
+          of: ConfigMap
+      - matchRegex:
+          path: data["vm.args"]
+          pattern: "\\+Q 1048576"
+
+  - it: sets RELEASE_VM_ARGS and mounts vm-args by default
+    template: deployment.yaml
+    asserts:
+      - contains:
+          path: spec.template.spec.containers[0].env
+          content:
+            name: RELEASE_VM_ARGS
+            value: /etc/logflare/vm.args
+      - contains:
+          path: spec.template.spec.containers[0].volumeMounts
+          content:
+            name: vm-args
+            mountPath: /etc/logflare/vm.args
+            subPath: vm.args
+            readOnly: true
+      - contains:
+          path: spec.template.spec.volumes
+          content:
+            name: vm-args
+            configMap:
+              name: RELEASE-NAME-logflare-vm-args
+
+  - it: renders no ConfigMap when vmArgs is empty
+    set:
+      vmArgs: ""
+    template: vm-args-configmap.yaml
+    asserts:
+      - hasDocuments:
+          count: 0
+
+  - it: omits RELEASE_VM_ARGS when vmArgs is empty
+    set:
+      vmArgs: ""
+    template: deployment.yaml
+    asserts:
+      - notContains:
+          path: spec.template.spec.containers[0].env
+          content:
+            name: RELEASE_VM_ARGS
+            value: /etc/logflare/vm.args