How to use VLANs with multiple VMware ESXi hosts – Support Guides

Learn how to use VLAN tagging with VMware ESXi and OVHcloud's vRack to privately network your ESXi VMs together across hosts, regardless of location.

Requirements

At least two dedicated servers with ESXi installed (hardware requirements are in the Broadcom documentation) in a vRack.
Access to the ESXi Host Client (this information will have been sent via email after installing ESXi on your OVHcloud server).
A VM in your ESXi environment (How to Create a VM in VMware ESXi).

Instructions

Adding a vSwitch to an ESXi host

OVHcloud Dedicated Servers that support vRack are equipped with separate network paths for public and private (vRack) traffic. By default, however, ESXi will only configure a vSwitch for the public NIC. To connect our VMs over vRack, we will add a vSwitch to each host to use the NIC connected to vRack.

NOTE: All steps taken in a single ESXi host will have to be mirrored in each additional host if you wish for VMs on different hosts to communicate with each other.

To create a new vSwitch, click Networking > Virtual switches tab > Add standard virtual switch.

In the pop-up window, enter a vSwitch Name, choose vmnic1 for Uplink 1, and click Add.

In this example, the vRack-connected NIC is named vmnic1, but the name may be different on your host. You will only be able to choose that NIC for Uplink 1, since it's the only physical NIC not already attached to a vSwitch.

Creating a new port group on the vSwitch

To create a new port group, select the Port groups tab and click Add port group.

In the pop-up window, enter a Name, choose a VLAN ID, select the vSwitch created above, and click Add.

NOTE: By default, the VLAN ID will read "0," which is for untagged traffic. We recommend using VLAN tagging for an added layer of security; select any number between 2 and 4,000 for this number. Then use the same number for every other VM you wish to network together.

Creating a private NIC on a VM on the new port group

NOTE: In this example, we assume that we are changing settings on a preexisting VM. However, these same settings can be changed during the creation of a VM in ESXi.

To create a new NIC on your VM, click Virtual Machines and select your VM.

Make sure your VM is powered off, and then click Edit.

In the pop-up window, click Add a network adapter, select the port group created above, and click SAVE.

Configuring the network

For examples of how to set up networking on VMs running Ubuntu or Windows Server, see the tabs below. If you are running a different operating system, the setup required will vary.

The final step to configuring networking for VLAN-tagged traffic is to assign the NIC a private IP address to use for routing traffic. To do so, first access your server via SSH or the built-in ESXi console. Then, enter the following command to find the name of your second interface.

$ ip add

NOTE: By default, ESXi will assign the name ens192 to the second NIC if you are using the VMXNET3 adapter. If you are not using the default adapter, it will be the second interface in the list.

We will configure a NIC that is not already configured for public networking (one without an IP address already assigned to it). To do so, we will need to open the Netplan configuration file using the following command:

$ sudo vi /etc/netplan/01-netcfg.yaml

Once in the file, edit it to appear as follows. If you have already configured the public NIC, create the entry for the private NIC, directly below the public one. Do not delete the public NIC from the file.

# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd
  ethernets:
    ens192:
      dhcp4: no
      addresses: [192.168.0.1/24]

NOTE: You can use any private IP address you choose that isn't already utilized by another VM on the vRack. The CIDR notation will determine the subnet on which the different IP addresses can communicate with one another. All IPs on a VLAN must exist on the same subnet.

Save and exit the file and then apply the changes using the following command:

$ sudo netplan apply

NOTE: For Windows to transmit any traffic to other devices, you will need to ensure that it is discoverable by other devices. When configuring the network, make sure that it is labeled "Private" so that other computers on the same network can discover it.

If you are running Windows Server, you will need to configure the second Ethernet interface with a private IP address to route VLAN-tagged traffic. To do so, log in to your Windows VM and then enter the Server Manager. Click Local Server on the left-hand sidebar and then click IPv4 address assigned by DHCP, IPv6 enabled button next to the second Ethernet adapter.

Now right-click the second Ethernet adapter and select Properties from the drop-down menu.

Double-click the Internet Protocol Version 4 (TCP/IPv4) button.

Choose Use the following IP address and enter a private IP address and subnet mask.

Remember that all private IP addresses communicating over a VLAN need to be on the same subnet. Define your subnet mask according to your needs.

NOTE: Do not enter a default gateway for the private (VLAN) adapter. Your public network adapter already has a default gateway configured for internet routing. Adding a second default gateway on the private adapter can cause routing conflicts and ambiguous outbound traffic.

Click OK when you are done.

Go further

For more information and tutorials, please see our other Dedicated Servers support guides or explore the guides for other OVHcloud products and services.