Software Defined Data Center (SDDC)

Cloud Computing is becoming more and more important for companies. Having your own hardware resources on site are a thing of the past, as are the associated costs, particularly high acquisition costs – the option of obtaining the required computing and storage capacities from a provider is very attractive.

Thanks to virtualised computing and storage power, as well as software defined networking, it is now even possible to rent complete data centre structures: Providers no longer only provide storage and server performance, but also network components such as switches, load balancers or firewalls as virtual resources that can be conveniently controlled using software. It is therefore hardly surprising that not only providers but also an increasing number of experts see these Software Defined Data Centres (SDDCs) as the data centre model of the future. The following sections explain why this is the case and how a software-controlled network works at all.

The software-defined virtualisation and provision of computing power (software defined computing) and storage space (software defined storage) have long established themselves within the portfolio of cloud providers. For some time now, the future-oriented IaaS model, in which a higher-level software acts as a central control unit, has also been used for administrating network structures (software defined networking).

A software defined data centre (SDDC) combines these three application-driven infrastructure services so that users can build their own customised data centre. Using the appropriate software, typical components like routers, switches, servers load balancers or firewalls can be individually booked and organised in the virtual network without having to purchase their own hardware. Instead, it is provided by the IaaS provider, and they are also responsible for the maintenance and security of the devices. If certain components are no longer needed, they can be removed from the SDDC at any time. You can also add additional hardware to a software defined data centre if larger structures are required.

Just like any software-defined IT resource, the separation of control and data levels plays an important role in SDDCs: All control functions are abstracted in advance from the integrated hardware and implemented in higher-level software, which then functions as the control centre (or “Control Plane”) of the virtual data centre. It takes over all tasks that go beyond simple data processing at the data level (“Data Plane”) – for example, determining where an application or a certain process is executed, which path a data package should take, or exactly where files should be stored.

Communication with the various devices works through standardised protocols like OpenFlow, BGP (Border Gateway Protocol) or NETCONF. These enable the control plane to uniformly control and expand the functions of the hardware components, regardless of which manufacturer they come from. In addition, it is not necessary to implement changes on each individual device, since the corresponding information can also be passed on centrally – with just a few clicks, or even automatically, through the software defined data centre’s control software.

Software defined data centres make full use of virtualisation technology, making administration a mammoth task. The virtual components and the underlying hardware must be formed into a unit that is still easy to oversee and manage. In particular, the fluid boundaries between real and virtual data centres present operators with major challenges: For example, it is necessary to perfectly harmonise the mediating tools between the virtual and physical environment. Otherwise, an error may be reported for a virtual component even though it originates at the physical level.

The combination of the various software defined services (computing, storage, networking) is also more difficult than it might appear: The individual software-defined IaaS options are of varying maturity and have also established various protocols and interfaces, which must also be combined in the SDDC. This is also reflected in the hardware, which on the one hand must be easy to virtualise and on the other hand should support the interaction of various virtual server, storage and network components beyond its own hardware limits. This is the only way in which the software defined data centre can guarantee the multi-client capable use of the infrastructure.

The goal of software-defined services is maximum flexibility, automation and efficiency. To achieve this goal, hardware dependency must be overcome and a maximum degree of virtualisation must be achieved. The result is IT infrastructures without the physical limitations of traditional environments, which can be flexibly adapted to user requirements and scaled accordingly. After virtualised mass storage, server and network solutions, this approach is now being extended to a complete virtual data centre in the form of the software defined data centre, which has various advantages over the traditional data centre with dedicated hardware:

• Simplified hardware management: SDDCs replace isolated hardware technologies and enable centralised management of all embedded components. This makes it easier for providers to build and deploy resources and for customers to control and monitor them. Companies also benefit from the fact that the purchase of their own hardware is completely eliminated.
• Lower costs: Software defined data centres are more cost effective than traditional data centres for two reasons. On the one hand, a large part of the hardware is cheaper due to the lack of control logic; on the other hand, simple scalability helps customers keep costs as low as possible.
• High planning reliability: By setting up or using a software-defined data centre, you are well equipped for future technological developments. New functions can be integrated much more easily than in a traditional data centre. The good scalability also allows selected resources to be increased or reduced at any time.
• High reliability: SDDC solutions are very fail-safe because the software-based architecture easily compensates for hardware failure. For this purpose, the corresponding workloads are transferred to other components within a very short time, without manual access to the failed devices being necessary.
• Increased security: In contrast to the traditional infrastructure of data centres, the SDDC model enables all security-relevant information to be bound to the virtual machines themselves. Security deficiencies, e.g. due to inadequate configurations, can therefore practically be ruled out.
• Less know-how required: Standardisation, open protocols and manufacturer-independent programming means not just more flexibility, but also less dependence on specialist knowledge. The use of a software defined data centre therefore makes it a large number of additional training courses and trained specialist personnel unnecessary.

Software-defined services like a software defined data centre are becoming increasingly important due to their great advantages over traditional infrastructure models. However, renting a complete data centre is only a possibility for few companies. For this reason, IaaS providers’ SDDC offerings have so far mainly been aimed at enterprise customers who either want to supplement their own structures with virtual data centre structures (hybrid solution) or want to replace them step by step. In the long term, the use of software-controlled storage, computing power and network components pays off in particular if the following scenarios are targeted:

• Optimisation of your own data centre: Those who already have their own data centre take the next logical step with an SDDC – especially if software defined storage and software defined servers already play a role in the current structures.
• Dynamic connections: A software defined data centre is perfect for establishing dynamic connections with individual bandwidth allocation and guaranteed Quality of Service (QoS) between different locations. In this way, different company locations (internal or partner) or used data centers can be connected efficiently.
• Optimal network access control: SDDC provides a centralised and convenient way to define permissions for all users and devices accessing an integrated network, including access control restrictions, service chain integration and appropriate quality of service.
• Automation of IT processes: Virtual data centres greatly simplify the work of administrators – especially through the high degree of automation of processes that are usually done manually. The software-defined approach is therefore a decisive factor in relieving the burden on existing IT personnel.
• Consolidation of classic cloud services: Traditional cloud services basically follow the same approach as software-based services by focusing on virtualisation and policies. However, merging the services of different providers is often a major challenge that can be mastered with a software defined data centre.

Software Defined Data Centres combine all relevant IaaS offerings like storage, computing power and networks in virtual structures that replace a traditional data centre one-to-one and can be controlled via a central software solution. Typical problems like complications when merging or expanding the functions of devices from different manufacturers or when increasing or decreasing resources are a thing of the past in a fully virtual data centre. If the relevant hardware is even better equipped for use in the SDDC, enterprise companies will probably not be able to avoid this flexible and highly scalable technology in the future.