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Showing posts from November, 2015

Open Virtual Switch (OVS) Deep Dive: How L2 Agent "wires" a new VM

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The basics of the OVS (Open Virtual Switch) and OpenStack Neutron module were described in my previous post. Time to get a bit deeper into the OVS.

A Virtual Machine (VM), a part from the CPU and Memory, needs the Connectivity.  L2 Agent (OVS in this case, or an External L2 agent) is used to connect the VM to the physical port. OVS resides on the Hypervisor of each OpenStack Node.

To understand how exactly the L2 Agent Works, and how it provides the VM connectivity to the “outside world”, we first need to get a bit “deeeper” into the Linux-y nature of the OVS, and understand all the Bridge Types, what they are used for and how they interconnect. This might look a bit complicated in the beginning, specially if you come from traditional Networking background.

These are the OVS Bridge Types:

br-int (Integration Bridge): All the VMs use the VIF (Virtual Interfaces) to connect to the Integration Bridge.br-eth (Ethernet Bridge): OVS Ethernet Bridge is the entity that allows us to decide if w…

OpenStack Neutron and OVS (Open Virtual Switch) translated to the Network Engineers language

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Introduction to Open Virtual Switch (OVS)

IaaS (Infrastructure as a Service) is provided by a group of different, interconnected Services. OpenStack is an Operating System that makes the IaaS possible, by controlling the “pools” of Compute, Storage and Networking within a Data Center using the Dashboard (later we´ll discuss some more about what Dashboard really is).



NaaS (Network as a Service) is a part we will mainly focus on. in this post NaaS is what OpenStack brings to Networking. The NaaS is in charge of configuring all the Network Elements (L2, L3 and Network Security) using the APIs (Application Programmable Interfaces). Users use the NaaS as the interface that allows them to add/configure/delete all the Network Elements, such as Routers, Load Balancers and Firewalls.

Neutron is an OpenStack module in charge of Networking. Neutron works using its Plug-ins. A Neutron Plug-in is used for different external mechanism, such as:

Open vSwitch (OVS), or external L2 Agents.SDN Controllers…