Chapter 7. Network of Virtual Networks

In this chapter, we are going to take an in-depth look at how we can create a virtualized network within a virtual environment. We will learn what the network building blocks are that make up the Proxmox hypervisor and how it manages both internal and external network connectivity. We will examine several network diagrams to see how Proxmox can be utilized to create an entire colony of virtual machines connected with virtual networks. We will also take a look at the Open vSwitch implementation in Proxmox along with the network configuration file, network bonding, VLAN, and so on. We can create dozens of virtual machines at will, but without a planned network model, we will fail to run an efficient virtual environment. If we compare virtual machines with bricks as the building blocks, then it is the network that acts as the mortar to create from a basic hut to a cathedral.

In this chapter, we will cover the following topics:

• The definition of a virtual...

Exploring a virtual network

A virtual network is a software-defined network where all links and components may or may not have direct interaction with physical hardware. In most cases, direct interaction with physical hardware is made by the hypervisor or host controller. All links between virtual machines, virtual switches, virtual bridges, and virtual network interfaces are made completely virtually. The following are the two types of network virtualization:

• External network virtualization: This consists of several local networks operating as one virtual network. Physical LANs can be in the same location or spread over multiple locations. Usually, external virtualization is a cloud network service-based model that multiple companies can use to connect their multisite virtual environment for a service fee. External network virtualization can be easily achieved by combining several internal virtual networks into a single virtualized network using a WAN or the Internet using a technology...

A physical network versus a virtual network

We will now see the difference between a physical network and a virtual network. The following diagram represents a physical network without a virtualization platform:

The following diagram represents virtualization as the main infrastructure:

Before we dive into virtual network building blocks, we need to understand how networks are set up in the preceding diagrams. Both the diagrams represent the same office setup where the main administrative department is on the second floor, and the accounting department is on the fourth floor of the building. It is apparent from the diagrams that a physical network is less complex than a virtual network, but by leveraging virtualization, we can cut costs, increase efficiency, reduce hardware maintenance complexity, and increase portability.

A physical network

In the physical network diagram, there is no virtualization platform set up. The network is set up with physical devices, such as firewalls, switches, servers...

Networking components in Proxmox

We will now take a look at the networking components of Proxmox, which will allow virtual machines to communicate with or be segmented from other internal machines as well as the Internet.

Virtual Network Interface Card (vNIC)

Virtual Network Interface Card (vNIC) is a software-defined representation of a Media Access Control (MAC) interface of physical network interfaces. It is basically a virtual network card for a virtual machine. Multiple vNICs can share a physical network interface of a host node. In a way, networking starts with vNIC when a virtual machine sends data to reach other virtual machines or networking devices within a virtual environment or physical environment. In the following diagram, the virtual machine has two virtual network interfaces assigned with an Intel e1000 driver. Both of them are configured with the bridge vmbr601:

Intel e1000 is a Linux kernel driver used to virtualize Intel architecture-based virtual network interfaces. This...

Open vSwitch

Licensed under open source Apache 2.0, Open vSwitch is a multi-layered, enterprise grade virtual switch born specifically to be used in modern virtual networks of a virtual environment. This is similar to a virtual bridge of Linux but has more ability and robust features. A question often asked is why one should choose Open vSwitch over time and industry-proven traditional Linux bridge and networking. Once we understand the features and advantages Open vSwitch provides for a virtual network, the answer becomes obvious.

Features of Open vSwitch

The following are some of the features that make Open vSwitch a better option than standard Linux networking:

• Security: Open vSwitch provides a high-degree of security by allowing you to set policies per VM virtual interface.

• LACP and VLAN-aware: Open vSwitch fully supports the LACP link aggregation and VLAN tagging. We can configure one single Open vSwitch with multiple VLAN tags, thus reducing management overhead of many virtual bridges...

Sample virtual networks

At this stage, we have covered components of virtual networks within the Proxmox cluster environment. We know the components Proxmox uses to hold everything together.

We are going to take a look at a few virtual environment scenarios to solidify our understanding of networking in a Proxmox virtual environment. These are scenario-based network diagrams and some of them are taken from a real production environment.

Network #1 – Proxmox in its simplest form

This is a small-scale Proxmox cluster with three nodes and two subnets within the virtual environment. Each Proxmox node has two NICs, and both the bridges vmbr0 and vmbr1 are attached to eth0 and eth1, respectively. Each bridge has three virtual machines attached to them. Outside the virtual environment, there is a physical switch, which connects Proxmox nodes, and an admin console for all management work. This is Proxmox in its simplest form in a production environment. This type of network can be used as a learning...

A multitenant virtual environment

Multitenancy is a very frequently used word in the world of cloud computing, where a virtual environment is regularly used by different clients from different organizations set up with fully isolated networks. Multitenancy is an integral part for a service provider who provides Infrastructure-as-a-Service (IaaS) to many clients.

Tip

To know more about cloud computing, visit http://en.wikipedia.org/wiki/Cloud_computing.

In this type of setup, the service provider hosts or "rents out" computing time and storage space to their clients. Because of the standard monthly subscription or SLA-based payment method required for this type of service, the term multitenancy quickly gained popularity. Basically, a multitenant virtual environment is where several isolated networks coexist on the same platform without interfering with one another. Almost all public datacenters are multitenancy platforms.

Multitenancy is not new in the world of information. The first multitenant...

Summary

We were very busy in this lively chapter. We looked at the differences between physical and virtual networks. We learned about the Proxmox network components that make up a Proxmox-based virtual network. We also learned about Open vSwitch and its components to create a really complex virtual network. We even got to analyze a few network diagrams from the basic to the advanced to get a better understanding of how the Proxmox virtual network really comes to life.

Proxmox provides all the tools we need to build any level of virtual network. It is up to the network administrator's imagination, the company's budget, and the need to foresee how all pieces should come together to form a well-designed and efficient virtual network. The best part is that any mistake is easily correctable in a virtual environment. We can always go back and change things until we are satisfied. For this very reason, a virtual network is always evolving. Over time, a virtual network becomes an extension of the...