feat(helm chart): Make env vars configurable and auto configure go runtime

Signed-off-by: Stevo Slavic <[email protected]>

Author: sslavic

charts/metrics-server/CHANGELOG.md

@@ -14,6 +14,11 @@
 
 ## [UNRELEASED]
 
+### Added
+
+- Extra environment variables configuration support.
+- Automatic container Go runtime (GOMAXPROCS, GOMEMLIMIT) configuration based on assigned resources, with opt-out support. ([#1412](https://github.com/kubernetes-sigs/metrics-server/pull/1412)) [@sslavic](https://github.com/sslavic)
+
 ## [3.12.0] - TBC
 
 ### Changed

charts/metrics-server/README.md

@@ -54,6 +54,8 @@ The following table lists the configurable parameters of the _Metrics Server_ ch
 | `podDisruptionBudget.maxUnavailable` | Set the `PodDisruptionBudget` maximum unavailable pods.                                                                                                                                                                                                          | `nil`                                                                          |
 | `defaultArgs`                        | Default arguments to pass to the _metrics-server_ command.                                                                                                                                                                                                       | See _values.yaml_                                                              |
 | `args`                               | Additional arguments to pass to the _metrics-server_ command.                                                                                                                                                                                                    | `[]`                                                                           |
+| `setAutoGoEnvVars`                   | Whether to automatically set GOMAXPROCS and GOMEMLIMIT env vars for all the containers.                                                                                                                                                                          | `true`                                                                         |
+| `extraEnvVars`                       | Additional environment variables to pass to the _metrics-server_ container.                                                                                                                                                                                      | `[]`                                                                           |
 | `livenessProbe`                      | Liveness probe.                                                                                                                                                                                                                                                  | See _values.yaml_                                                              |
 | `readinessProbe`                     | Readiness probe.                                                                                                                                                                                                                                                 | See _values.yaml_                                                              |
 | `service.type`                       | Service type.                                                                                                                                                                                                                                                    | `ClusterIP`                                                                    |
@@ -64,6 +66,7 @@ The following table lists the configurable parameters of the _Metrics Server_ ch
 | `addonResizer.securityContext`       | Security context for the _metrics_server_container.       |                                                                                                                                             _See values.yaml |
 | `addonResizer.image.repository`      | addon-resizer image repository                                                                                                                                                                                                                                   | `registry.k8s.io/autoscaling/addon-resizer`                                    |
 | `addonResizer.image.tag`             | addon-resizer image tag                                                                                                                                                                                                                                          | `1.8.19`                                                                       |
+| `addonResizer.extraEnvVars`          | Additional environment variables to pass to the _addon-resizer_ container.                                                                                                                                                                                       | `[]`                                                                           |
 | `addonResizer.resources`             | Resource requests and limits for the _nanny_ container.                                                                                                                                                                                                          | `{ requests: { cpu: 40m, memory: 25Mi }, limits: { cpu: 40m, memory: 25Mi } }` |
 | `addonResizer.nanny.cpu`             | The base CPU requirement.                                                                                                                                                                                                                                        | `0m`                                                                           |
 | `addonResizer.nanny.extraCPU`        | The amount of CPU to add per node.                                                                                                                                                                                                                               | `1m`                                                                           |

charts/metrics-server/templates/deployment.yaml

@@ -72,6 +72,20 @@ spec:
           {{- range .Values.args }}
             - {{ . }}
           {{- end }}
+          env:
+            {{- if .Values.setAutoGoEnvVars }}
+            - name: GOMAXPROCS
+              valueFrom:
+                resourceFieldRef:
+                  resource: requests.cpu
+            - name: GOMEMLIMIT
+              valueFrom:
+                resourceFieldRef:
+                  resource: limits.memory
+            {{- end }}
+          {{- with .Values.extraEnvVars }}
+            {{- toYaml . | nindent 12 }}
+          {{- end }}
           ports:
           - name: https
             protocol: TCP
@@ -110,6 +124,19 @@ spec:
               valueFrom:
                 fieldRef:
                   fieldPath: metadata.namespace
+            {{- if .Values.setAutoGoEnvVars }}
+            - name: GOMAXPROCS
+              valueFrom:
+                resourceFieldRef:
+                  resource: requests.cpu
+            - name: GOMEMLIMIT
+              valueFrom:
+                resourceFieldRef:
+                  resource: limits.memory
+            {{- end }}
+          {{- with .Values.addonResizer.extraEnvVars }}
+            {{- toYaml . | nindent 12 }}
+          {{- end }}
           command:
             - /pod_nanny
             - --config-dir=/etc/config

charts/metrics-server/values.yaml

@@ -98,6 +98,12 @@ defaultArgs:
 
 args: []
 
+# Specifies whether to automatically set GOMAXPROCS and GOMEMLIMIT environment
+# variables for all containers relative to the assigned resources.
+setAutoGoEnvVars: true
+
+extraEnvVars: []
+
 livenessProbe:
   httpGet:
     path: /livez
@@ -130,6 +136,7 @@ addonResizer:
   image:
     repository: registry.k8s.io/autoscaling/addon-resizer
     tag: 1.8.20
+  extraEnvVars: []
   securityContext:
     allowPrivilegeEscalation: false
     readOnlyRootFilesystem: true