A logical view on a virtual datacentre services architecture

A couple of years ago, I wrote a post about a logical view of an End-User Computing (EUC) architecture (which provides a platform for Modern Workplace). It’s served me well and the model continues to be developed (although the changes are subtle so it’s not really worth writing a new post for the 2019 version).

Building on the original EUC/Modern Workplace framework, I started to think what it might look like for datacentre services – and this is something I came up with last year that’s starting to take shape.

Just as for the EUC model, I’ve tried to step up a level from the technology – to get back to the logical building blocks of the solution so that I can apply them according to a specific client’s requirements. I know that it’s far from complete – just look at an Azure or AWS feature list and you can come up with many more classifications for cloud services – but I think it provides the basics and a starting point for a conversation:

Logical view of a virtual datacentre environment

Starting at the bottom left of the diagram, I’ll describe each of the main blocks in turn:

  • Whether hosted on-premises, co-located or making use of public cloud capabilities, Connectivity is a key consideration for datacentre services. This element of the solution includes the WAN connectivity between sites, site-to-site VPN connections to secure access to the datacentre, Internet breakout and network security at the endpoints – specifically the firewalls and other network security appliances in the datacentre.
  • Whilst many of the SBBs in the virtual datacentre services architecture are equally applicable for co-located or on-premises datacentres, there are some specific Cloud Considerations. Firstly, cloud solutions must be designed for failure – i.e. to design out any elements that may lead to non-availability of services (or at least to fail within agreed service levels). Depending on the organisation(s) consuming the services, there may also be considerations around data location. Finally, and most significantly, the cloud provider(s) must practice trustworthy computing and, ideally, will conform to the UK National Cyber Security Centre (NCSC)’s 14 cloud security principles (or equivalent).
  • Just as for the EUC/Modern Workplace architecture, Identity and Access is key to the provision of virtual datacentre services. A directory service is at the heart of the solution, combined with a model for limiting the scope of access to resources. Together with Role Based Access Control (RBAC), this allows for fine-grained access permissions to be defined. Some form of remote access is required – both to access services running in the datacentre and for management purposes. Meanwhile, identity integration is concerned with integrating the datacentre directory service with existing (on-premises) identity solutions and providing SSO for applications, both in the virtual datacentre and elsewhere in the cloud (i.e. SaaS applications).
  • Data Protection takes place throughout the solution – but key considerations include intrusion detection and endpoint security. Just as for end-user devices, endpoint security covers such aspects as firewalls, anti-virus/malware protection and encryption of data at rest.
  • In the centre of the diagram, the Fabric is based on the US National Institute of Standards and Technology (NIST)’s established definition of essential characteristics for cloud computing.
  • The NIST guidance referred to above also defines three service models for cloud computing: Infrastructure as a Service (IaaS); Platform as a Service (PaaS) and Software as a Service (SaaS).
  • In the case of IaaS, there are considerations around the choice of Operating System. Supported operating systems will depend on the cloud service provider.
  • Many cloud service providers will also provide one or more Marketplaces with both first and third-party (ISV) products ranging from firewalls and security appliances to pre-configured application servers.
  • Application Services are the real reason that the virtual datacentre services exist, and applications may be web, mobile or API-based. There may also be traditional hosted server applications – especially where IaaS is in use.
  • The whole stack is wrapped with a suite of Management Tools. These exist to ensure that the cloud services are effectively managed in line with expected practices and cover all of the operational tasks that would be expected for any datacentre including: licensing; resource management; billing; HA and disaster recovery/business continuity; backup and recovery; configuration management; software updates; automation; management policies and monitoring/alerting.

If you have feedback – for example, a glaring hole or suggestions for changes, please feel free to leave a comment below.

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