Because of the nature of SDN, and specifically the automation available with Cisco's Application Centric Infrastructure, ACI works really well with cloud orchestration tools such as OpenStack. I was able to be at the OpenStack Summit in Tokyo last week and gave a vBrownBag TechTalk about why Cisco ACI makes OpenStack even better.

So, how does ACI work with OpenStack and perhaps even make it better? First, ACI offers distributed and scalable networking. It supports Floating IP addresses in OpenStack. If you're not familiar with Floating IPs, they are essentially a pool of publicly routable IP addresses that you purchase from an ISP and assign to instances. This would be especially useful for instances, or VMs, like web servers. It also saves CPU cycles by putting the actual networking in the Nexus 9000 switches that make up the ACI fabric. Since these switches are built to forward packets, and that's what they're good at, why not save the CPU cycles for other things like running instances?

OpenStack doesn't natively work with Layer 4-7 devices like firewalls and load balancers. With ACI we can stitch in these necessary network services in an automated and repeatable way. We do this in a way that doesn't sacrifice visibility as well. While it's important that we're able to automate things, especially in a private or public cloud that is constantly changing and updating, if we lose visibility, we lose the ability to troubleshoot easily. In the demo, shown in the video above, you will see just how easy it is to troubleshoot problems in ACI. We also get the ability to preemptively strike before a problem causes issues on the network by offering easily interpreted health scores for the entire fabric, including hardware and end point groups.

ACI is also a very secure model. Not only does it use a white-list model where traffic is denied by default and only allowed when explicitly configured that way, it will also give more security when it comes to multi-tenancy. In a strict overlay solution, if a hypervisor is attacked or owned the multi-tenancy model could be deemed insecure. In the ACI fabric the security is done at the port level. So even if a hypervisor is attacked the tenants will be safe.

In recent versions of ACI we are able to use OpFlex as a southbound protocol to communicate between OpenStack and ACI. By using OpFlex we get a deeper integration and more visibility into the virtual environment of OpenStack. Instead of attaching hypervisor servers to a physical domain in ACI we can attach them into a VMM (Virtual Machine Manager) domain. This allows us to learn which instances or VMs are on which physical server. It will also automatically learn IP addresses, MAC addresses, states and other information. We can also see which networks or portgroups contain which hypervisors and instances within our OpenStack environments.

For more information on how Cisco ACI works with OpenStack you can go to http://cisco.com/go/aci