23rd October 2017

Software Defined – How did we get here?

It’s widely acknowledged that to understand the present, and to try and predict the future you must know and understand the past.

The current data centre landscape is a complex place.  Virtualisation of compute resources with VMware has been the de facto standard for over a decade. The move to software defined infrastructure has been gathering momentum and VMware’s vision for the software defined data centre (SDDC) looks set to augment vSphere offerings and continue to dominate the private data centre landscape.

So how did we get here?  How did we go from that initial wow factor that came from first experiencing VMotion to the VMware SDDC?  I think it all comes down to one building block.

Elastic Sky X

The earlier versions of ESX gave us something that perhaps we’ve forgotten.  Virtualisation has become so commonplace, so pervasive that we no longer see the magic.  We’ve become so used to working with virtual machines that we have missed the fundamental building block introduced in ESX, that has made everything afterwards possible.

No, I’m not talking about VMotion, HA or DRS.  I’m talking about the encapsulation and abstraction of the physical server into a few files.  The software defined server.

Perhaps without even realising it, server encapsulation changed the way that we think about the data centre.  The abstraction of the physical server to a virtual machine and capture of the physical server and ability to describe it in a set of files. Everything that followed in the VMware technology stack (and you could argue in the wider industry) is either directly or indirectly attributable to this technology and philosophy.

Without the software defined server; VMotion doesn’t come along, blowing a few minds along the way, and begin to re-write the art of the possible.  Sharing and defining cluster level resources with DRS isn’t possible and VM level HA no longer exists… Imagine for a moment having to deliver all the services you deliver today, using other clustering technologies.

Later, into the evolution of the data-centre we wouldn’t get Storage VMotion, Fault Tolerance, VM level backup and restore, vSphere replication and vShield endpoints.  Without server encapsulation and abstraction, the software defined server, the data centre landscape today would look very different indeed.


The VMware technologies that underpin the Software Defined Data Centre are vSphere, VSAN and NSX.  The philosophy that created the software defined server, has been applied to the networking and storage stacks.

Both technologies are analogous and draw on the same philosophy that gave rise to the software defined server. A virtualised network is a software container that presents logical network components to connected workloads. Virtualised storage abstracts the underlying physical storage through a virtual data plane.

All very familiar, and therein lies the genius.

Server virtualisation and encapsulation is pervasive in the data centre, with a decade of evidence backing it as a technology it is so successful that many have forgotten the magic it supports.  In the SDDC we see these features expanded to finally deliver on the promise of full data centre automation tooling with vRealize.

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The Cloud

Now that VMware are delivering on the Software Defined Data Centre, that data centre itself can be considered as encapsulated into a set of files.  Just in the same way that the software defined server became portable, the software defined datacentre is becoming portable.  We haven’t quite got to a point of data centre VMotion, but at the point where the data centre is a set of files, the limitation is now bandwidth.  VMConAWS is also now available, providing many organisations a realistic chance of moving to the cloud, without having to re-architect and retrain an organisation.

The software defined server philosophy continues in the public and private clouds, not just through IaaS offerings, but through detaching and abstracting the applications from traditional operating system dependency. With PaaS, Containerisation and Serverless or function based computing being the logical successors to the software defined server.

The Future

Predicting the future is the path of madness.  Strategies change and black swans are always out there ready to disrupt all plans.  However, this is after all a blog post and as such I should probably take a view.

When you look at the physical components that make up the data centre, there isn’t really anything left to virtualise and encapsulate. Compute, Storage and Networking has been covered.  Further advancement down this path is unlikely.  Where growth might be seen is in the security stack, as security management moves closer to the VMs from the network edge.

In parallel with virtualisation, machine learning and artificial intelligence have also been rapidly advancing.  With the SDDC bringing all datacentre components together, gathering logs and information about data centre performance is now easier than it has ever been.  Might it be reasonable to suggest, that in the future Machine Learning and AI will work with the data generated by the SDDC to provide a smarter data centre?  A data centre that can pinpoint problems, resolve issues, predict load requirements, change operating configurations, that can learn, adapt and intelligently suggest routes for data centre evolution?

Following the logical progression of the software defined server to serverless computing patterns, it is also not premature to suggest that a modern IT infrastructure will be one that uses no resources and incurs no charge when it isn’t actively being used.  Just like physical servers became the exception in a virtual world, it will be interesting to see for how long the SDDC remains relevant in a serverless world.