You’d be forgiven for assuming that cloud computing was well on the way to killing off ‘bare metal’ IT deployments. After all, the hype around enterprise infrastructure in recent years has all been about AWS and the other public cloud IaaS giants, about cloud-native architectures, edge computing, containerisation and the rest.
Not much of the discussion focuses on what is still the basic unit of IT infrastructure, the humble server. In the post-virtualisation world we live in, do we get anywhere even talking about servers as distinct ‘units’ at all. Isn’t what really matters in compute terms their pooled resources, abstracted, divied up and shared via the hypervisor?
In a post-COVID world where the cloud, with all its inherent flexibility, is forecast to become even more of a dominant force, it might sound strange, paradoxical even, to hear that the bare metal infrastructure market is also predicted to grow apace.
Then there’s the phrase ‘bare metal cloud’ being bandied around, that sounds at first like an oxymoron. Don’t cloud services by definition run in virtualised environments, making the idea of a ‘bare metal’ cloud, where computing assets run directly on the machine, a contradiction in terms?
By some definitions, yes – but not all. Increasingly, the term Infrastructure-as-a-Service, once by common consensus used only to refer to cloud-based hosted infrastructure services, has come to incorporate any form of remote infrastructure provision by a third-party – including hiring out dedicated servers.
From that, it’s a small step to the term ‘bare metal cloud’ – no longer a contradiction, but a reflection of how the possibilities of hosted infrastructure are becoming richer and more multi-faceted (we can put the hybrid cloud concept in the same category).
After all, bare metal cloud and dedicated servers are one and the same thing – the renting out of specific machines in a data centre to a single tenant, giving them greater control over security, capacity, traffic speeds and so on compared to what is possible when you share virtualised resources. Bare metal, virtualised – either way, it all involves the renting out and management of infrastructure resources hosted in a data centre. Which is why it is all now considered part of the same ‘cloud’ family.
Avoiding the noisy neighbours
Latest market forecasts suggest that infrastructure buyers are more than happy to have the bare metal option available under the cloud umbrella. The bare metal market is predicted to boom on the back of the general surge in cloud adoption post-COVID, increasing four-fold to $16.4bn by 2026 with a CAGR of 24.1%.
So why is bare metal infrastructure set to grow so significantly? On the one hand, nothing much has changed – the benefits and attractions of dedicated/bare metal servers remain the same as they have always been.
Cloud deployments in virtualised environments might have transformed IT as we once knew it because of the flexibility and scalability they offer (not to mention cost savings). But when it comes to running mission critical applications, enterprises have long been concerned with the ‘noisy neighbour’ aspect of crowded shared resource environments – the fact that the jostling for virtualised disk space and memory can, at times, impair QoS and performance.
With your own dedicated non-virtualised server, however, you’re never having to compete for resources like this. Yes, you don’t get the same on-demand scalability that being able to spin up new VMware machines as and when required affords. But within the limits of a single server (or however many you link together in series), you get more processing power, more consistent I/O performance and more control over the application stack.
Containers over bare metal
Away from what we might call the ‘traditional’ benefits of bare metal infrastructure, there’s another important trend that is driving renewed interest in running servers without a hypervisor layer. Containers have typically been talked about as a ‘flavour’ of virtualisation, with the abstraction containers execute happening a step up the stack from the original VMware/hypervisor model, virtualising the operating system rather than the server resources.
Perhaps because of this association between containerisation and virtualisation, it has been common to run containers on top of VMware – stacking virtualisation on virtualisation, if you like. But there’s nothing to say containers have to be deployed like this. They can be deployed directly on the ‘bare metal’ of the server – and indeed there are benefits to doing so.
For example, containers run directly on the server use resources much more efficiently than when there is an intermediary hypervisor layer – some estimates put it at 90% efficiency versus 15%. That’s because containers already have all the resources they need to run the application they are part of. There is no need for the extra layer of resource abstraction a hypervisor provides, although abstraction from the host OS does offer its own benefits, such as portability across environments.
There is no firm consensus about whether deploying containers on bare metal is better than running them on top of VMware or vice versa. Most of the time, it is a horses for courses decision – when your primary goal is optimising resource utilisation and efficiency, bare metal probably works best, when you are aiming for flexibility and portability (those old cloud benefits again), you opt for a virtualized environment.
What is clear is that, as enterprise IT strategies increasingly pivot towards application development and, with the twin objectives of scale and efficiency in mind, adoption of container technology grows with it, the fact that there are multiple infrastructure options for how you deploy your containerised environment will have a big impact on the infrastructure sector going forward.
Just as bare metal now sits comfortably in the broadened ‘cloud’ family of remotely hosted services, the non-virtualised deployment option for containers, and the benefits it offers, is sure to keep bare metal relevant and indeed growing for years to come.