VMware Integrated OpenStack integrates different OpenStack components in VMware, which enables administrators to...
easily manage and deploy OpenStack services from the vSphere Web Client interface. One such OpenStack component is Neutron, the core component for software-defined networking. In this article we'll discuss what Neutron is, how it integrates in VMware Integrated OpenStack and take a closer look at Neutron networking.
In a cloud environment, software-defined networking (SDN) is an important component. SDN allows for the creation of logical broadcast domains over a physical infrastructure that doesn't have to be in the same broadcast domain. Neutron does this by providing a pluggable architecture that allows for seamless integration in a traditional VMware infrastructure.
In OpenStack Neutron networking, there is a clear distinction between the data plane and logical network services. The data plane provides physical network services, where hypervisors are connected by using physical switches. Neutron networking uses plug-ins to communicate to the data plane and adds logical network services to that. These include logical routers, load balancers, firewalls and anything else that is used to define networking in a flexible way.
The Neutron OpenStack component was developed as a pluggable architecture that can communicate with any physical network infrastructure. In order to use OpenStack in a typical Linux-only hypervisor environment, you must first provide the Open vSwitch network plug-in. This plug-in runs on the Linux hypervisor and regulates access to the physical network cards. At the same time, it provides advanced features such as tunnel interfaces which allow cloud instances running on one hypervisor to have a direct, broadcast-level communication with instances running on another hypervisor.
This tunneling interface can best be compared to a VPN tunnel. In a VPN, the end user works at a remote location and connects to the corporate server directly. In this case, "directly" means the VPN client for the server is seen as a client on the same LAN as the server. The fact that many routers are used in the physical infrastructure beneath is completely hidden by the VPN software.
Neutron networking needs to create these logical connections as well. It does so by using specific protocols like Generic Routing Encapsulation and Virtual Extensible LAN. These protocols define the SDN infrastructure in the different plug-ins used in OpenStack Neutron.
While OpenStack runs Open vSwitch by default, this plug-in is only for Linux hypervisors. VMware Integrated OpenStack is different, as VIO is exclusively for ESXi hypervisors in a vSphere environment. In vSphere environments, the preferred method for implementing SDN is VMware NSX, a plug-in that integrates without any problems in OpenStack Neutron. In fact, VMware is among the most significant code contributors to the Neutron project because of NSX.
Compared to the Open vSwitch plug-in, VMware NSX provides many advanced features, which makes it the platform of choice for customers running OpenStack exclusively in VIO environments as well as those running OpenStack in environments where multiple hypervisors are used.
VMware has been working to make NSX a format that integrates well in the software-defined data center, for instance, by collaborating with partners to provide advanced management options and by producing a series of well-developed tools for the NSX administrator.
Even beyond VIO, NSX is an interesting plug-in, as it has been developed to run on top of any hypervisor. This means it can be used on XenSever, KVM, Hyper-V and other platforms, which makes it possible to integrate NSX in any cloud. Due to this, VMware NSX is a much more compelling choice than the default Open vSwitch plug-in that runs only on KVM.
In VIO, however, the administrator doesn't have the wide range of choices available in open source OpenStack. This is because the underlying ESXi hypervisor doesn't support just any SDN layer, but uses NSX as the preferred SDN plug-in. Of course, there's nothing wrong with that, as NSX was developed as a plug-in to integrate with a wide range of hardware platforms and software offerings.
Essential guide to Neutron networking
Answer to common NSX questions
What's missing from OpenStack Neutron?