add server-chart extraEnv

content/rancher/v2.x/en/installation/ha/helm-rancher/chart-options/_index.md

@@ -28,6 +28,7 @@ weight: 276
 | `auditLog.maxBackups` | 1 | `int` - maximum number of audit log files to retain |
 | `auditLog.maxSize` | 100 | `int` - maximum size in megabytes of the audit log file before it gets rotated |
 | `debug` | false | `bool` - set debug flag on rancher server |
+| `extraEnv` | [] | `list` - set additional environment variables for rancher. |
 | `imagePullSecrets` | [] | `list` - list of names of Secret resource containing private registry credentials |
 | `ingress.extraAnnotations` | {} | `map` - additional annotations to customize the ingress |
 | `proxy` | "" | `string` -  HTTP[S] proxy server for Rancher |
@@ -53,6 +54,15 @@ By default enabling Audit Logging will create a sidecar container in the Rancher
 
 Set the `auditLog.destination` to `hostPath` to forward logs to volume shared with the host system instead of streaming to a sidecar container. When setting the destination to `hostPath` you may want to adjust the other auditLog parameters for log rotation.
 
+### Set Extra Environment Variables
+
+You can set extra environment variable for Rancher server with `extraEnv`. This list uses the same `name` and `value` keys as the container manifest definitions. Remember to quote the values.
+
+```plain
+--set 'extraEnv[0].name=CATTLE_SYSTEM_DEFAULT_REGISTRY'
+--set 'extraEnv[0].value=http://registry.example.com/'
+```
+
 ### Import `local` Cluster
 
 By default Rancher server will detect and import the `local` cluster it's running on.  User with access to the `local` cluster will essentially have "root" access to all the clusters managed by Rancher server.