One of the most popular networking command in Linux is the ifconfig command. It lets you see (and configure) IP address for network interface. It also shows the MAC address for each interface. The MAC address and the IP address viewing is probably the most common reason for using the ifconfig command. In addition the ifconfig command works with physical network interface (like eth0..) and virtual network interface (like Tap interface etc).
In the next installment of “What I learnt today” or WILT, I briefly touch upon Network Namespace. I came across Namespace as part of my ongoing study of OpenStack networking. Namespaces are powerful constructs in Linux that allows you to create a copy of the TCP/IP network stack -all the way from the Ethernet interfaces (L2), routing tables etc.
If you were to ask someone “what is the most popular open source hypervisor” chances are that the answer will be KVM. Indeed KVM (or Kernel-based Virtual Machine) has played a key role in the open source Linux based virtualization environment. However is it really a hypervisor? Moreover, can KVM by itself run virtual machines? We will delve more into such questions in this blog. We will also understand the relationship between KVM and QEMU (Quick EMUlator).
In the previous blog of this series we saw that using Linux bridge we can connect a virtual Ethernet port of a VM to the physical Ethernet port of the hypervisor server. Let us now focus a bit more on these virtual ports to see what happens behind the scenes to make virtual networking actually work.
Software defined networking (SDN) is the current wave sweeping the networking industry. And one of the key enablers of SDN is virtual networking. While SDN and virtual networking are in vogue these days, the support for virtual networking is not a recent development. And Linux bridge has been the pioneer in this regard.