Document a workaround for installing helm behind a proxy

doc/topics/autodevops/index.md

@@ -1168,6 +1168,27 @@ There is no documented way of using private container registry with Auto DevOps.
 We strongly advise using GitLab Container Registry with Auto DevOps in order to
 simplify configuration and prevent any unforeseen issues.
 
+### Installing Helm behind a proxy
+
+GitLab does not yet support installing [Helm as a GitLab-managed App](../../user/clusters/applications.md#helm) when
+behind a proxy. Users who wish to do so must inject their proxy settings
+into the installation pods at runtime, for example by using a
+[`PodPreset`](https://kubernetes.io/docs/concepts/workloads/pods/podpreset/):
+
+```yml
+apiVersion: settings.k8s.io/v1alpha1
+kind: PodPreset
+metadata:
+  name: gitlab-managed-apps-default-proxy
+  namespace: gitlab-managed-apps
+spec:
+   env:
+    - name: http_proxy
+      value: "PUT_YOUR_HTTP_PROXY_HERE"
+    - name: https_proxy
+      value: "PUT_YOUR_HTTPS_PROXY_HERE"
+```
+
 ## Troubleshooting
 
 - Auto Build and Auto Test may fail in detecting your language/framework. There

doc/user/clusters/applications.md

@@ -67,6 +67,11 @@ required to install all the other applications. It is installed in its
 own pod inside the cluster which can run the `helm` CLI in a safe
 environment.
 
+NOTE: **Note:**
+Installing Helm as a GitLab-managed App behind a proxy is not supported,
+but a [workaround](../../topics/autodevops/index.md#installing-helm-behind-a-proxy)
+is available.
+
 ### Cert-Manager
 
 > Introduced in GitLab 11.6 for project- and group-level clusters.