Add reference page about webproxy

Author: mortenlj

docs/workloads/reference/webproxy.md

@@ -0,0 +1,29 @@
+---
+tags: [workloads, reference, webproxy]
+conditional: [tenant, nav]
+---
+
+# Webproxy
+
+In Navs on-premises environments, workloads that need to make external HTTP(S) requests must set `webproxy` to `true` in their [application spec](../../workloads/application/reference/application-spec.md#webproxy).
+
+When `webproxy` is enabled, the platform provides a set of environment variables to configure the proxy settings for your workload.
+
+## Linux 
+Most Linux applications should auto-detect these settings from the `$HTTP_PROXY`, `$HTTPS_PROXY` and `$NO_PROXY` environment variables (and their lowercase counterparts).
+
+## Java
+
+Java applications can start the JVM using parameters from the `$JAVA_PROXY_OPTIONS` environment variable.
+To do this, you either need a launcher script that copies the value from `JAVA_PROXY_OPTIONS` to `JDK_JAVA_OPTIONS`, 
+or you can set the `JDK_JAVA_OPTIONS` environment variable directly in your [application spec](../application/reference/application-spec.md#env).:
+
+```
+env:
+- name: JDK_JAVA_OPTIONS
+  value: $(JAVA_PROXY_OPTIONS)
+```
+
+This takes advantage of [Kubernetes Dependent Environment Variables](https://kubernetes.io/docs/tasks/inject-data-application/define-interdependent-environment-variables/), which allows you to use the value of one environment variable in another.
+
+Since environment variables set by the platform are defined before the application variables, you can refer to the `JAVA_PROXY_OPTIONS` variable when setting `JDK_JAVA_OPTIONS`.