[stable/cluster-autoscaler] Allow individual envs from secrets (#16901)

This commit adds the `extraEnvSecrets` config to be a map in the format:
```
envFromSecret:
  <env var name>:
    name: <secret name>
    key: <secret key>
```
This adds more flexibility by allowing to expose selected keys from a
secret and also allowing for a different name for the env variable.

The new behavior is identical to the existing `envFromConfigMap` config.

Signed-off-by: Cezar Sa Espinola <cezarsa@gmail.com>

stable/cluster-autoscaler/Chart.yaml

@@ -2,7 +2,7 @@ apiVersion: v1
 description: Scales worker nodes within autoscaling groups.
 icon: https://github.com/kubernetes/kubernetes/blob/master/logo/logo.png
 name: cluster-autoscaler
-version: 4.0.1
+version: 4.1.0
 appVersion: 1.13.7
 home: https://github.com/kubernetes/autoscaler
 sources:

stable/cluster-autoscaler/README.md

@@ -148,8 +148,9 @@ Parameter | Description | Default
 `extraArgs` | additional container arguments | `{}`
 `podDisruptionBudget` | Pod disruption budget | `maxUnavailable: 1`
 `extraEnv` | additional container environment variables | `{}`
-`envFromConfigMap` |  additional container environment variables from a configmap | `[]`
-`envFromSecret` | additional container environment variables from secret | `nil`
+`envFromConfigMap` | additional container environment variables from a configmap | `{}`
+`envFromSecret` | secret name containing keys that will be exposed as envs | `nil`
+`extraEnvSecrets` | additional container environment variables from a secret | `{}`
 `nodeSelector` | node labels for pod assignment | `{}`
 `podAnnotations` | annotations to add to each pod | `{}`
 `deployment.apiVersion` | apiVersion for the deployment | `extensions/v1beta1`

stable/cluster-autoscaler/templates/deployment.yaml

@@ -149,6 +149,13 @@ spec:
                   name: {{ default (include "cluster-autoscaler.fullname" $) $value.name }}
                   key: {{ required "Must specify key!" $value.key }}
           {{- end }}
+          {{- range $key, $value := .Values.extraEnvSecrets }}
+            - name: {{ $key }}
+              valueFrom:
+                secretKeyRef:
+                  name: {{ default (include "cluster-autoscaler.fullname" $) $value.name }}
+                  key: {{ required "Must specify key!" $value.key }}
+          {{- end }}
           {{- if .Values.envFromSecret }}
           envFrom:
             - secretRef: