Virtual networking labs – building a virtual router with iptables and Linux namespaces

When you are trying to understand virtual networking, container networks, micro segmentation and all this, sooner or later the day will come where you will have to deal with iptables, the built-in Linux firewall mechanism. After evading the confrontation with the full complexity of this remarkable beast for many years, I have recently decided to … Continue reading Virtual networking labs – building a virtual router with iptables and Linux namespaces →

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 … Continue reading Virtual networking labs – using OpenFlow →

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 … Continue reading Virtual networking labs – Open vSwitch in practice →

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 … Continue reading Virtual networking labs – a short introduction to Open vSwitch →

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 - … Continue reading Virtual networking labs – overlay networks →

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 … Continue reading Virtual networking labs – virtual Ethernet networks with VLAN tags →

Using Ansible with a jump host

For a more advanced setup 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 … Continue reading Using Ansible with a jump host →