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The hyper-converged network benefits from commingling HCI, SDN

Merging software-defined networking with hyper-converged infrastructure platforms should simplify and ease the deployment, scaling and management of hyper-converged networks.

Simplifying IT operations is the most valuable feature enterprises can get from hyper-converged infrastructure. Although HCI eliminates the need to manage storage separately from compute, it does make the hyper-converged network platform far more critical to the success of the overall infrastructure.

Enter software-defined networking. It has been a long time coming, but we're finally starting to see HCI merge with the software-defined network (SDN) to simplify network management. We may be in the early days of the commingling of HCI with SDN, but there are already well-known HCI problem areas that integration can resolve.

Ease initial HCI deployment

I've observed some patterns while helping customers with first-time HCI deployments. The first is that if there's a problem during deployment, it will be with the hyper-converged network.

HCI requires each node to connect to multiple networks: hypervisor management, VMotion migration, the HCI storage cluster, out-of-band hardware management and all of the VM networks. These networks may be virtual LANs (VLANs) trunked to fast network interface cards (NICs) or they can be delivered to different physical NICs. Most often, it's a combination of trunks and isolated NICs.

One single misconfiguration between the physical network and the HCI platform will either cause the install to fail or prevent reliable VM networking. Having an SDN that can take part in the initial HCI setup with two-way data sharing should eliminate misconfiguration.

It has been a long time coming, but we're finally starting to see HCI merge with the software-defined network to simplify network management.

Most HCI platforms have a deployer to complete the initial cluster setup, and this deployer should be able to talk to the SDN to coordinate the cluster and hyper-converged network configuration. Some SDN products use the Preboot Execution Environment (PXE) and Open Network Install Environment to deploy an OS on white box switches, and the same PXE could be used as the HCI deployer for the complete deployment integration between SDN and HCI. Having the SDN integrated with your HCI in this manner could remove one of the biggest stumbling blocks of HCI deployments.

Simplify ongoing HCI changes

Often, new applications inside new VMs means HCI platforms must have access to new networks. Conventionally, this means submitting help desk tickets to add VLANs to many physical switch ports and then matching virtual network updates. Then comes more help desk tickets and troubleshooting as the network and virtualization teams identify who got which parts wrong.

If you integrate SDN with HCI, all this becomes a simple software policy change to make the network available to the HCI hosts, which are then automatically configured to match the physical network. A single software change that coordinates the physical and virtual networks reduces the chances of misconfiguration.

The other common change is scaling out an HCI cluster by adding new nodes. Just like the initial deployment, hyper-converged network changes are non-trivial and must be coordinated. The same SDN integration that eased the initial cluster deployment could simplify the scale-out expansion of your HCI platforms, as well.

What about the vendors?

VMware would say I'm looking at SDN all wrong. Their physical network is a simple forwarding plane and their SDN is inside the hypervisor. There's deep integration between VMware vSphere and VMware NSX, with all the work being done in the hypervisor and a straightforward physical network. VMware vSphere also offers deployment features, such as auto-deploy, host profiles and distributed switches, which can ease deployment and change activities. These VMware features could do with some more simplification, however.

Big Switch Networks Inc. recently announced a validated design where its Big Cloud Fabric SDN is integrated with the Nutanix Prism manager. The integration fully automates networking for Nutanix node deployment in the initial cluster build and as the hyper-converged network cluster scales out. Big Switch integrates with both VMware vSphere on Nutanix and VxRail, as well as with Nutanix's own Acropolis hypervisor for initial deployment and ongoing changes, such as when VMs require access to new networks.

I expect Hewlett Packard Enterprise (HPE) will make some progress with HCI and SDN integration, as well. HPE acquired Plexxi last year, and I always thought the Plexxi networking technology would integrate nicely into an HCI platform, such as HPE SimpliVity. Plexxi already integrates into vSphere for functions such as guaranteed bandwidth for VMotion events. So, hopefully, we'll see full integration between Plexxi and SimpliVity and, perhaps, more Plexxi integration with other hyper-converged infrastructures, such as vSphere or even some of the Linux-based HCI platforms.

What about Cisco? The most prominent network vendor in enterprise IT has Application Centric Infrastructure as its SDN product and HyperFlex for HCI. Cisco also has plenty of software-defined features in the network hardware of its Unified Computing System Blade Servers. All the parts are clearly there, but I don't see simplification when you put them all together -- at least, not yet.

Early days, great potential

It may still be early for the integration of software-defined networking and hyper-converged Infrastructure. However, that integration has the potential to simplify some significant pain points for customers deploying and maintaining HCI, particularly on a large scale.

This was last published in February 2019

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How do you foresee software-defined networking simplifying the deployment, scaling and management of hyper-converged networks?