Virtual networking labs – using OpenFlow

In the last few posts, we have already touched on the OpenFlow protocol that plays a central role in most SDNs. Today, we will learn more on OpenFlow and again use Open vSwitch to see the protocol in action. OpenFlow – the basics Recall from our previous post that OpenFlow is a protocol that the…More

Virtual networking labs – Open vSwitch in practice

In the last post, we have discussed the architecture of Open vSwitch and how it with a control plane to realize an SDN. Today, we will make this a bit more tangible by running two hands-on labs with OVS. The labs in this post are modelled after some of the How-to documents that are part…More

Virtual networking labs – a short introduction to Open vSwitch

In the previous posts, we have used standard Linux tools to establish and configure our network interfaces. This is nice, but becomes very difficult to manage if you need to run environments with hundreds or even thousands of machines. Open vSwitch (OVS) is an Open source software switch which can be integrated with SDN control…More

Virtual networking labs – overlay networks

In the last post, we have looked at virtual networking on the Ethernet level. In modern cloud environments, a second class of virtual networks has gained importance, which uses higher level protocols to tunnel Ethernet frames. These networks are called overlay networks, and we will start to look at them in this post. VXLAN –…More

Virtual networking labs – virtual Ethernet networks with VLAN tags

In the previous posts, we have mainly been looking at virtual networking within one single physical hosts. This is nice, but to build cloud environments, we need to establish virtual networks across several physical hosts. In this post, we will start to look into technologies that make this possible and learn how VLAN tagging supports…More

Using Ansible with a jump host

For an OpenStack project using Ansible, I recently had to figure out how to make Ansible work with a jump host. After an initial phase of total confusion, I finally found my way through the documentation and various sources and ended up with several working configurations. This post documents what I have learned on that…More

Virtual networking labs – more on bridges

In the previous post, we have seen how a software-defined Linux bridge can be established and how it transparently connects two Ethernet devices. In this post, we will take a closer look at how to set up and monitor bridges and learn how VirtualBox uses bridges for virtual networking. Lab 6: setting up and monitoring…More

Virtual networking labs – VirtualBox internal networks and bridges

So far, we have been playing with virtual networking for one virtual machine, connected to the host. Now let us see how we can establish virtual networks connecting more than one machine. Lab3: Virtualbox host-only networking with more than one machine In this lab, we will connect two virtual machines that both use host-only networking.…More

Virtual networking labs – NAT and host-only networking with VirtualBox

When you work with virtualized environments, you will sooner or later realize that a large part of the complexity of such environments originates in the networking part. Networking itself is a non-trivial endeavor, and in the context of cloud and virtualization technology, you often stack different virtualization layers on top of each other. To provide…More