Proper network configuration is the cornerstone of a viable VMware vSphere infrastructure. To approach VMware networking, IT admins need to understand their vSphere hosts' physical interfaces and virtual switches. Learn how to plan for a virtual network with vSphere.
The first step in configuring a virtual network is integrating the vSphere deployment with the existing infrastructure. You'll need to know exact requirements of your existing infrastructure. For instance, if your network uses an Internet small computer system interface (iSCSI), storage area network (SAN) or network file system (NFS), you'll need more network interfaces in the vSphere hosts, compared to organizations that are on a Fibre Channel SAN. In most cases, six network interface cards (NICs) are the bare minimum; many hosts have 10, 12 or more NICs.
Setup guidelines for vSphere-based virtual networking
The management network, the network you'll use to connect to the ESXi hosts, needs at least one physical NIC, and best practice is to create two NICs for redundancy.
Before you start installing your first ESXi hosts, make a plan so you'll know what type of VMware networking configuration you're going to create.
VMware vMotion can be combined with the management network, but the best practice is to create a dedicated network for vMotion and make sure it's at least 1 Gb in size. As with the management network, use two interfaces and set them up redundantly.
If you're using vSphere Fault Tolerance for continuous resource uptime, you'll need a redundant pair of NICs for that as well, preferably 10 Gb. In VMware Fault Tolerance, the complete state of nodes needs to be synchronized, which creates a lot of network traffic.
Access to the storage network also needs a dedicated NIC, but only if you're using iSCSI or NFS. As on any other network interface, set up a redundant interface for storage. Do not set up a dedicated NIC for storage network access if you use Fibre Channel; this has its own dedicated interfaces.
After setting up these functions, consider end users who want to access virtual machines (VMs) on the vSphere network. Best practices for end-user access dictates you have a dedicated network interface comprised of a redundant pair of NICs. Up to this point, basic functionalities have required a minimum of eight NICs.
NIC configuration for the vSphere networking environment
The first challenge in configuring an NIC for vSphere is to set up the management network, which is done during a vSphere server installation. This is complicated: There are at least four network interfaces, but only one is connected to the management network or VLAN. From this point, interface denotes a pair of bundled NICs.
The vSphere installation program cannot see which interface is connected to which switch, so you might have to try connecting a couple of times before it works. Once the management network is correctly configured, you can complete the installation.
Next, you'll have to set up a virtual switch on the installed vSphere host. You need to set up at least one virtual switch for your vSphere network infrastructure.
The VMware virtual switch is software based in the VMkernel communication control tool. VMs configured to connect to virtual switches access the physical LAN. A standard switch, which has to be configured for each individual virtual host, will work. However, distributed switches are shared between entire clusters of ESXi hosts, making it easier to manage the virtual network.
You'll also need to determine how many virtual switches to configure for the virtual network. In some situations, you can connect all virtual hosts to the same virtual switch. In other cases, such as when physical security is a priority, it's best to create more than one virtual switch per host so traffic can be clearly separated.
Before you start installing your first ESXi hosts, make a plan so you'll know what type of VMware networking configuration you're going to create. This way, you'll buy the right hardware and set up the network in a way that makes it easier to administer down the road.
This was first published in October 2012