Merge pull request #42133 from ryanborMSFT/patch-24

Added info about second ipconfig using netplan

Author: ktoliver

includes/virtual-network-multiple-ip-addresses-os-config.md

@@ -47,65 +47,140 @@ ping -S 10.0.0.5 hotmail.com
 >For secondary IP configurations, you can only ping to the Internet if the configuration has a public IP address associated with it. For primary IP configurations, a public IP address is not required to ping to the Internet.
 
 ### Linux (Ubuntu 14/16)
-We recommend looking at the latest the documentation for your Linux distribution. 
+
+We recommend looking at the latest documentation for your Linux distribution. 
 
 1. Open a terminal window.
 2. Make sure you are the root user. If you are not, enter the following command:
 
-	```bash
-	sudo -i
-    ```
+   ```bash
+   sudo -i
+   ```
 
 3. Update the configuration file of the network interface (assuming ‘eth0’).
 
    * Keep the existing line item for dhcp. The primary IP address remains configured as it was previously.
    * Add a configuration for an additional static IP address with the following commands:
 
-       ```bash
-       cd /etc/network/interfaces.d/
-       ls
-       ```
+     ```bash
+     cd /etc/network/interfaces.d/
+     ls
+     ```
 
      You should see a .cfg file.
 4. Open the file. You should see the following lines at the end of the file:
 
+   ```bash
+   auto eth0
+   iface eth0 inet dhcp
+   ```
+
+5. Add the following lines after the lines that exist in this file:
+
+   ```bash
+   iface eth0 inet static
+   address <your private IP address here>
+   netmask <your subnet mask>
+   ```
+
+6. Save the file by using the following command:
+
+   ```bash
+   :wq
+   ```
+
+7. Reset the network interface with the following command:
+
+   ```bash
+   sudo ifdown eth0 && sudo ifup eth0
+   ```
+
+   > [!IMPORTANT]
+   > Run both ifdown and ifup in the same line if using a remote connection.
+   >
+
+8. Verify the IP address is added to the network interface with the following command:
+
+   ```bash
+   ip addr list eth0
+   ```
+
+   You should see the IP address you added as part of the list.
+
+### Linux (Ubuntu 18.04+)
+
+Ubuntu 18.04 and above have changed to `netplan` for OS network management. We recommend looking at the latest documentation for your Linux distribution. 
+
+1. Open a terminal window.
+2. Make sure you are the root user. If you are not, enter the following command:
+
 	```bash
-	auto eth0
-	iface eth0 inet dhcp
+	sudo -i
     ```
 
-5. Add the following lines after the lines that exist in this file:
+3. Create a file for the second interface and open it in a text editor:
 
 	```bash
-	iface eth0 inet static
-	address <your private IP address here>
-	netmask <your subnet mask>
+	vi /etc/netplan/60-static.yaml
     ```
 
-6. Save the file by using the following command:
+4. Add the following lines to the file, replacing `10.0.0.6/24` with your IP/netmask:
+
+	```bash
+    network:
+        version: 2
+        ethernets:
+            eth0:
+                addresses:
+                    - 10.0.0.6/24
+    ```
+
+5. Save the file by using the following command:
 
 	```bash
 	:wq
     ```
 
-7. Reset the network interface with the following command:
+6. Test the changes using [netplan try](http://manpages.ubuntu.com/manpages/cosmic/man8/netplan-try.8.html) to confirm syntax:
 
 	```bash
-	sudo ifdown eth0 && sudo ifup eth0
+	netplan try
     ```
 
-	> [!IMPORTANT]
-	> Run both ifdown and ifup in the same line if using a remote connection.
-	>
+> [!NOTE]
+> `netplan try` will apply the changes temporarily and roll the changes back after 120 seconds. If there is a loss of connectivity, please wait 120 seconds, and then reconnect. At that time, the changes will have been rolled back.
+
+7. Assuming no issues with `netplan try`, apply the configuration changes:
+
+	```bash
+	netplan apply
+    ```
 
 8. Verify the IP address is added to the network interface with the following command:
 
 	```bash
 	ip addr list eth0
     ```
 
-	You should see the IP address you added as part of the list.
+	You should see the IP address you added as part of the list. Example:
 
+	```bash
+    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
+        link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
+        inet 127.0.0.1/8 scope host lo
+        valid_lft forever preferred_lft forever
+        inet6 ::1/128 scope host
+        valid_lft forever preferred_lft forever
+    2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
+        link/ether 00:0d:3a:8c:14:a5 brd ff:ff:ff:ff:ff:ff
+        inet 10.0.0.6/24 brd 10.0.0.255 scope global eth0
+        valid_lft forever preferred_lft forever
+        inet 10.0.0.4/24 brd 10.0.0.255 scope global secondary eth0
+        valid_lft forever preferred_lft forever
+        inet6 fe80::20d:3aff:fe8c:14a5/64 scope link
+        valid_lft forever preferred_lft forever
+    ```
+    
 ### Linux (Red Hat, CentOS, and others)
 
 1. Open a terminal window.