feat: add extraEnv support to envoy-gateway controller deployment (#8733)

* feat: add extraEnv support to envoy-gateway controller deployment

Add deployment.envoyGateway.extraEnv to the gateway-helm chart values,
allowing operators to inject additional environment variables into the
controller container.

The controller deployment template currently hardcodes two env vars
(ENVOY_GATEWAY_NAMESPACE and KUBERNETES_CLUSTER_DOMAIN) with no way
to add more. This makes it impossible to configure behavior controlled
by standard environment variables (e.g. OTEL_METRICS_EXEMPLAR_FILTER,
GOGC, GOMEMLIMIT) without patching the deployment out-of-band.

Fixes #8732

Signed-off-by: Giri Kuncoro <girikuncoro@gmail.com>

Author: girikuncoro

charts/gateway-helm/README.md

@@ -70,6 +70,7 @@ helm uninstall eg -n envoy-gateway-system
 | config.envoyGateway | object | `{"extensionApis":{},"gateway":{"controllerName":"gateway.envoyproxy.io/gatewayclass-controller"},"logging":{"level":{"default":"info"}},"provider":{"type":"Kubernetes"}}` | EnvoyGateway configuration. Visit https://gateway.envoyproxy.io/docs/api/extension_types/#envoygateway to view all options. |
 | createNamespace | bool | `false` |  |
 | deployment.annotations | object | `{}` |  |
+| deployment.envoyGateway.extraEnv | list | `[]` | Additional environment variables for the envoy-gateway container. |
 | deployment.envoyGateway.image.repository | string | `""` |  |
 | deployment.envoyGateway.image.tag | string | `""` |  |
 | deployment.envoyGateway.imagePullPolicy | string | `""` |  |

charts/gateway-helm/templates/envoy-gateway-deployment.yaml

@@ -59,6 +59,9 @@ spec:
               fieldPath: metadata.namespace
         - name: KUBERNETES_CLUSTER_DOMAIN
           value: {{ .Values.kubernetesClusterDomain }}
+        {{- with .Values.deployment.envoyGateway.extraEnv }}
+        {{- toYaml . | nindent 8 }}
+        {{- end }}
         image: {{ include "eg.image" . }}
         imagePullPolicy: {{ include "eg.image.pullPolicy" . }}
         livenessProbe:

charts/gateway-helm/values.tmpl.yaml

@@ -42,6 +42,8 @@ deployment:
       tag: ""
     imagePullPolicy: ""
     imagePullSecrets: []
+    # -- Additional environment variables for the envoy-gateway container.
+    extraEnv: []
     resources:
       limits:
         memory: 1024Mi

site/content/en/latest/install/gateway-helm-api.md

@@ -34,6 +34,7 @@ The Helm chart for Envoy Gateway
 | config.envoyGateway | object | `{"extensionApis":{},"gateway":{"controllerName":"gateway.envoyproxy.io/gatewayclass-controller"},"logging":{"level":{"default":"info"}},"provider":{"type":"Kubernetes"}}` | EnvoyGateway configuration. Visit https://gateway.envoyproxy.io/docs/api/extension_types/#envoygateway to view all options. |
 | createNamespace | bool | `false` |  |
 | deployment.annotations | object | `{}` |  |
+| deployment.envoyGateway.extraEnv | list | `[]` | Additional environment variables for the envoy-gateway container. |
 | deployment.envoyGateway.image.repository | string | `""` |  |
 | deployment.envoyGateway.image.tag | string | `""` |  |
 | deployment.envoyGateway.imagePullPolicy | string | `""` |  |

test/helm/gateway-helm/deployment-extraenv.in.yaml

@@ -0,0 +1,13 @@
+global:
+  images:
+    envoyGateway:
+      image: "docker.io/envoyproxy/gateway-dev:latest"
+      pullPolicy: Always
+
+deployment:
+  envoyGateway:
+    extraEnv:
+    - name: OTEL_METRICS_EXEMPLAR_FILTER
+      value: always_off
+    - name: GOGC
+      value: "50"