feat(helm): support user-defined volumes and volumeMounts in microservices chart (#32233)

The componentized chart at helm/litellm had no way to mount extra
volumes into its deployments, so custom callback or SSO handler code
could not be mounted the way the docs describe for the monolithic
chart. Adds per-component volumes and volumeMounts values for gateway,
backend, and ui, merged with the existing gateway-config volume, plus
a helm-unittest suite for the chart wired into the helm unit test
workflow

Resolves LIT-4209

.github/workflows/helm_unit_test.yml

@@ -38,4 +38,6 @@ jobs:
           echo "Helm unittest plugin integrity verified: $ACTUAL_SHA"
 
       - name: Run unit tests
-        run: helm unittest -f 'tests/*.yaml' deploy/charts/litellm-helm
+        run: |
+          helm unittest -f 'tests/*.yaml' deploy/charts/litellm-helm
+          helm unittest -f 'tests/*.yaml' helm/litellm

helm/litellm/templates/backend/deployment.yaml

@@ -45,11 +45,16 @@ spec:
               value: /app/config/config.yaml
             {{- end }}
           {{- include "litellm.envFrom" .Values.backend | nindent 10 }}
-          {{- if .Values.gateway.config.create }}
+          {{- if or .Values.gateway.config.create .Values.backend.volumeMounts }}
           volumeMounts:
+            {{- if .Values.gateway.config.create }}
             - name: gateway-config
               mountPath: /app/config/config.yaml
               subPath: config.yaml
+            {{- end }}
+            {{- with .Values.backend.volumeMounts }}
+            {{- toYaml . | nindent 12 }}
+            {{- end }}
           {{- end }}
           {{- with .Values.backend.livenessProbe }}
           livenessProbe:
@@ -61,11 +66,16 @@ spec:
           {{- end }}
           resources:
             {{- toYaml .Values.backend.resources | nindent 12 }}
-      {{- if .Values.gateway.config.create }}
+      {{- if or .Values.gateway.config.create .Values.backend.volumes }}
       volumes:
+        {{- if .Values.gateway.config.create }}
         - name: gateway-config
           configMap:
             name: {{ include "litellm.gateway.fullname" . }}-config
+        {{- end }}
+        {{- with .Values.backend.volumes }}
+        {{- toYaml . | nindent 8 }}
+        {{- end }}
       {{- end }}
       {{- with .Values.backend.nodeSelector }}
       nodeSelector:

helm/litellm/templates/gateway/deployment.yaml

@@ -47,11 +47,16 @@ spec:
               value: {{ .Values.gateway.numWorkers | quote }}
             {{- end }}
           {{- include "litellm.envFrom" .Values.gateway | nindent 10 }}
-          {{- if .Values.gateway.config.create }}
+          {{- if or .Values.gateway.config.create .Values.gateway.volumeMounts }}
           volumeMounts:
+            {{- if .Values.gateway.config.create }}
             - name: gateway-config
               mountPath: /app/config/config.yaml
               subPath: config.yaml
+            {{- end }}
+            {{- with .Values.gateway.volumeMounts }}
+            {{- toYaml . | nindent 12 }}
+            {{- end }}
           {{- end }}
           {{- with .Values.gateway.livenessProbe }}
           livenessProbe:
@@ -63,11 +68,16 @@ spec:
           {{- end }}
           resources:
             {{- toYaml .Values.gateway.resources | nindent 12 }}
-      {{- if .Values.gateway.config.create }}
+      {{- if or .Values.gateway.config.create .Values.gateway.volumes }}
       volumes:
+        {{- if .Values.gateway.config.create }}
         - name: gateway-config
           configMap:
             name: {{ include "litellm.gateway.fullname" . }}-config
+        {{- end }}
+        {{- with .Values.gateway.volumes }}
+        {{- toYaml . | nindent 8 }}
+        {{- end }}
       {{- end }}
       {{- with .Values.gateway.nodeSelector }}
       nodeSelector:

helm/litellm/templates/ui/deployment.yaml

@@ -46,6 +46,10 @@ spec:
             {{- toYaml . | nindent 12 }}
             {{- end }}
           {{- include "litellm.envFrom" .Values.ui | nindent 10 }}
+          {{- with .Values.ui.volumeMounts }}
+          volumeMounts:
+            {{- toYaml . | nindent 12 }}
+          {{- end }}
           {{- with .Values.ui.livenessProbe }}
           livenessProbe:
             {{- toYaml . | nindent 12 }}
@@ -56,6 +60,10 @@ spec:
           {{- end }}
           resources:
             {{- toYaml .Values.ui.resources | nindent 12 }}
+      {{- with .Values.ui.volumes }}
+      volumes:
+        {{- toYaml . | nindent 8 }}
+      {{- end }}
       {{- with .Values.ui.nodeSelector }}
       nodeSelector:
         {{- toYaml . | nindent 8 }}

helm/litellm/tests/deployment_volumes_tests.yaml

@@ -0,0 +1,172 @@
+suite: test deployment volumes and volumeMounts
+templates:
+  - gateway/deployment.yaml
+  - gateway/configmap.yaml
+  - backend/deployment.yaml
+  - ui/deployment.yaml
+values:
+  - ./values/required.yaml
+tests:
+  - it: gateway renders only the config volume by default
+    template: gateway/deployment.yaml
+    asserts:
+      - equal:
+          path: spec.template.spec.volumes
+          value:
+            - name: gateway-config
+              configMap:
+                name: RELEASE-NAME-litellm-gateway-config
+      - equal:
+          path: spec.template.spec.containers[0].volumeMounts
+          value:
+            - name: gateway-config
+              mountPath: /app/config/config.yaml
+              subPath: config.yaml
+
+  - it: gateway merges user volumes and volumeMounts with the config volume
+    template: gateway/deployment.yaml
+    set:
+      gateway.volumes:
+        - name: custom-callbacks
+          configMap:
+            name: custom-callbacks
+      gateway.volumeMounts:
+        - name: custom-callbacks
+          mountPath: /app/custom_callbacks.py
+          subPath: custom_callbacks.py
+    asserts:
+      - equal:
+          path: spec.template.spec.volumes[0].name
+          value: gateway-config
+      - equal:
+          path: spec.template.spec.volumes[1]
+          value:
+            name: custom-callbacks
+            configMap:
+              name: custom-callbacks
+      - equal:
+          path: spec.template.spec.containers[0].volumeMounts[0].name
+          value: gateway-config
+      - equal:
+          path: spec.template.spec.containers[0].volumeMounts[1]
+          value:
+            name: custom-callbacks
+            mountPath: /app/custom_callbacks.py
+            subPath: custom_callbacks.py
+
+  - it: gateway renders user volumes even when config creation is disabled
+    template: gateway/deployment.yaml
+    set:
+      gateway.config.create: false
+      gateway.volumes:
+        - name: certs
+          secret:
+            secretName: tls-certs
+      gateway.volumeMounts:
+        - name: certs
+          mountPath: /etc/certs
+          readOnly: true
+    asserts:
+      - equal:
+          path: spec.template.spec.volumes
+          value:
+            - name: certs
+              secret:
+                secretName: tls-certs
+      - equal:
+          path: spec.template.spec.containers[0].volumeMounts
+          value:
+            - name: certs
+              mountPath: /etc/certs
+              readOnly: true
+
+  - it: gateway omits volumes when config creation is disabled and no user volumes are set
+    template: gateway/deployment.yaml
+    set:
+      gateway.config.create: false
+    asserts:
+      - isNull:
+          path: spec.template.spec.volumes
+      - isNull:
+          path: spec.template.spec.containers[0].volumeMounts
+
+  - it: backend merges user volumes and volumeMounts with the shared config volume
+    template: backend/deployment.yaml
+    set:
+      backend.volumes:
+        - name: sso-handler
+          configMap:
+            name: sso-handler
+      backend.volumeMounts:
+        - name: sso-handler
+          mountPath: /app/custom_sso.py
+          subPath: custom_sso.py
+    asserts:
+      - equal:
+          path: spec.template.spec.volumes[0].name
+          value: gateway-config
+      - equal:
+          path: spec.template.spec.volumes[1]
+          value:
+            name: sso-handler
+            configMap:
+              name: sso-handler
+      - equal:
+          path: spec.template.spec.containers[0].volumeMounts[1]
+          value:
+            name: sso-handler
+            mountPath: /app/custom_sso.py
+            subPath: custom_sso.py
+
+  - it: backend renders user volumes even when config creation is disabled
+    template: backend/deployment.yaml
+    set:
+      gateway.config.create: false
+      backend.volumes:
+        - name: data
+          emptyDir: {}
+      backend.volumeMounts:
+        - name: data
+          mountPath: /data
+    asserts:
+      - equal:
+          path: spec.template.spec.volumes
+          value:
+            - name: data
+              emptyDir: {}
+      - equal:
+          path: spec.template.spec.containers[0].volumeMounts
+          value:
+            - name: data
+              mountPath: /data
+
+  - it: ui renders no volumes by default
+    template: ui/deployment.yaml
+    asserts:
+      - isNull:
+          path: spec.template.spec.volumes
+      - isNull:
+          path: spec.template.spec.containers[0].volumeMounts
+
+  - it: ui renders user volumes and volumeMounts
+    template: ui/deployment.yaml
+    set:
+      ui.volumes:
+        - name: nginx-config
+          configMap:
+            name: custom-nginx
+      ui.volumeMounts:
+        - name: nginx-config
+          mountPath: /etc/nginx/conf.d
+    asserts:
+      - equal:
+          path: spec.template.spec.volumes
+          value:
+            - name: nginx-config
+              configMap:
+                name: custom-nginx
+      - equal:
+          path: spec.template.spec.containers[0].volumeMounts
+          value:
+            - name: nginx-config
+              mountPath: /etc/nginx/conf.d

helm/litellm/tests/values/required.yaml

@@ -0,0 +1,4 @@
+database:
+  writer:
+    host: postgres.example.com
+    dbname: litellm

helm/litellm/values.yaml

@@ -124,6 +124,11 @@ gateway:
   extraEnv: [] # Add extra environment variables to the gateway
   envConfigMaps: [] # Add extra environment variables to the gateway from config maps
   envSecrets: [] # Add extra environment variables to the gateway from secrets
+  # Additional volumes on the gateway Deployment (e.g. a ConfigMap holding
+  # custom callback / SSO handler code, mounted next to the proxy config).
+  volumes: []
+  # Additional volumeMounts on the gateway container.
+  volumeMounts: []
   config:
     create: true
     proxy_config: {}
@@ -167,6 +172,10 @@ backend:
   extraEnv: []
   envConfigMaps: []
   envSecrets: []
+  # Additional volumes on the backend Deployment.
+  volumes: []
+  # Additional volumeMounts on the backend container.
+  volumeMounts: []
   image:
     repository: ghcr.io/berriai/litellm-backend
     tag: ""
@@ -206,6 +215,10 @@ ui:
   extraEnv: []
   envConfigMaps: []
   envSecrets: []
+  # Additional volumes on the ui Deployment.
+  volumes: []
+  # Additional volumeMounts on the ui container.
+  volumeMounts: []
   image:
     repository: ghcr.io/berriai/litellm-ui
     tag: ""