Merge pull request #5063 from comwrap/rabbitmq-remove-notice

Align RabbitMQ installation guide

Author: erikmarr

guides/v2.3/install-gde/prereq/install-rabbitmq.md

@@ -7,9 +7,6 @@ functional_areas:
   - Setup
 ---
 
-{:.bs-callout .bs-callout-warning"}
-You must install and configure [RabbitMQ](http://rabbitmq.com) _before_ installing Magento.
-
 ## RabbitMQ Overview {#overview}
 
 RabbitMQ is an open source message broker that offers a reliable, highly available, scalable and portable messaging system.
@@ -68,13 +65,13 @@ The RabbitMQ server is included on CentOS, but the version is often old. RabbitM
 1. Download [rabbitmq-server-3.5.6-1.noarch.rpm](https://www.rabbitmq.com/releases/rabbitmq-server/v3.5.6/rabbitmq-server-3.5.6-1.noarch.rpm){:target="_blank"}.
 2. Run the following commands as a user with root permissions:
 
-```bash
-rpm --import https://www.rabbitmq.com/rabbitmq-signing-key-public.asc
-```
-
-```bash
-yum install rabbitmq-server-3.5.6-1.noarch.rpm
-```
+    ```bash
+    rpm --import https://www.rabbitmq.com/rabbitmq-signing-key-public.asc
+    ```
+    
+    ```bash
+    yum install rabbitmq-server-3.5.6-1.noarch.rpm
+    ```
 
 Refer to [Installing on RPM-based Linux](https://www.rabbitmq.com/install-rpm.html){:target="_blank"} for more information.
 
@@ -88,9 +85,9 @@ Review the official RabbitMQ documentation to configure and manage RabbitMQ. Pay
 * Starting and stopping the broker
 * System limits
 
-## Connect RabbitMQ to {{site.data.var.ce}} or {{site.data.var.ee}}
+## Install Magento with RabbitMQ and connect to {{site.data.var.ce}} or {{site.data.var.ee}} 
 
-Add the following command line parameters when you install {{site.data.var.ce}} or {{site.data.var.ee}}:
+If you installed Magento after you installed RabbitMQ, add the following command line parameters when you install {{site.data.var.ce}} or {{site.data.var.ee}}:
 
 `--amqp-host="<hostname>" --amqp-port="5672" --amqp-user="<user_name>" --amqp-password="<password>" --amqp-virtualhost="/"`
 
@@ -105,12 +102,31 @@ where:
 |`--amqp-virtualhost`|The virtual host for connecting to RabbitMQ. The default is `/`.
 |`--amqp-ssl`|Indicates whether to connect to RabbitMQ. The default is `false`. If you set the value to true, see Configure SSL for more information.|
 
+## Connect RabbitMQ to {{site.data.var.ce}} or {{site.data.var.ee}} 
+
+If you already had Magento installed and you want to connect it to RabbitMQ, add a `queue` section in the `<install_directory>/app/etc/env.php` file so that it is similar to the following:
+
+```php
+'queue' =>
+  array (
+    'amqp' =>
+    array (
+      'host' => 'rabbitmq.example.com',
+      'port' => '11213',
+      'user' => 'magento',
+      'password' => 'magento',
+      'virtualhost' => '/'
+     ),
+  ),
+```
+
+Then, run `bin/magento setup:upgrade` to apply the changes and create the required queues in RabbitMQ.
+
 ## Configure SSL
 
 To configure support for SSL, edit the `ssl` and `ssl_options` parameters in the `<install_directory>/app/etc/env.php` file so that they are similar to the following:
 
 ```php
-
 'queue' =>
   array (
     'amqp' =>