Hybrid clouds are starting to become more and more attractive for larger cnterprises. The claim is that hybrid clouds combine the benefits of both private and public clouds, but omit their drawbacks. Although this sounds great, let’s look at the challenges we face when we start to design and build a hybrid cloud:
Infrastructure as a service (IaaS) layer
On the IaaS layer, the main benefit we see in a hybrid cloud environment is that of leveraging the elasticity of public cloud resources, but maintaining a higher level of security for sensitive corporate data and applications by using a private cloud.
To address the security concerns for certain data and applications, a strong governance model together with adequate security policies need to be developed. It must be made crystal clear where applications and data are allowed to be placed and what the rational is behind these policies.
When applications scale out into public clouds to cover peak loads, we need to have a closer look at data placement. Not only for the sake of security, but this time also for the sake of performance. If an application requires a high amount of data, this application might not be suited for such a scenario unless, we have designed that properly beforehand (adequate network bandwidths, data replication, and so on).
Another challenging topic about hybrid clouds on the IaaS layer is their management. Clients who go for a full integrated hybrid cloud need to consider how to include the public cloud service catalog and automated provisioning into their local processes and infrastructure. Not all public cloud service providers offer open APIs or comply with open standards, but that’s a prerequisite for a seamless integration.
Challenges even grow when we consider managed public cloud services. Beside the technical boundaries of wide area network and data center locations, a split management responsibility comes with a large backpack of issues, which must be addressed. Monitoring, ticketing, backup and restore, and user management are just some of them. The service provider usually feels responsible only up to the operating system layer, sometimes also for middleware and databases, but very rarely for customer-specific applications. Those client specific applications must be operated by the clients themselves and therefore integrated into their systems management systems.
Software as a service (SaaS) layer
On the SaaS layer, a hybrid setup is less likely because of elasticity, but usually purely because of functionality. In this scenario, certain business functions are covered by a SaaS solution from an external service provider.
The challenge with this setup is to transport the required data to and from the public SaaS. First, the data that needs to be transferred must be identified, then, a secure interface must be developed to ensure the correct data is reliably fed into the remote software service, and result data is transferred back to the local environment. Because of the variety of data, and local and remote application combinations, not many standard software products are available to implement this linkage. IBM Cast Iron is one of them and provides a data field to data field link between many software products such as SAP and Salesforce.com.
Summary
A hybrid cloud is a complex animal, and preparation and design are key to address its challenges. However, most of these challenges can be solved, either by technology (Tivoli Service Automation Manager, Cast Iron, IBM Hybrid Cloud Integrator) or by governance and organization. Once established, a hybrid cloud is a very powerful asset combining today’s enterprise requirements with flexibility and cost efficiency!