Posted by Stefan Wesner 12 March 2009.

After reading and hearing everywhere that “Cloud Computing/Storage/…” is to be the successor of Grid*, I was wondering if one could do “Business Experiments in the Cloud”, similar to the ones we did (and still do) for the EC project BEinGRID – Business Experiments in Grid.

As well as requiring a clear business case for each pilot implementation, the Business Experiments also have to show why a distributed, cross-organizational solution is beneficial and why several service providers are needed. The offered services range from a thin abstraction layer provider (e.g. computing cycles or data storage) up to more complex and sophisticated services (e.g. licensing provider, product database provider) which are more in line with the coarse grained concept expected from a Service Oriented Architecture (SOA) solution.

For many of the delivered services that are not tightly coupled to a specific resource (such as a radio telescope) or internal data stores that cannot exported due to legal constraints, cloud services could be used to realize these services. After all, most services do not care if they are provided using a physical infrastructure or a virtualized one. So from this viewpoint, yes, we could have: Business Experiments in Clouds!

Another key element of many of the experiments is that the collaboration with other companies in a Virtual Organisation (VO) is always a compromise between the potential benefit (e.g. cost savings, integration of additional expertise and information) and the associated risks (e.g. dependency on an externally controlled service, …). The proposed solutions for increasing the certainty of service delivery by: binding providers to Service Level Agreements (SLAs); using semantically enriched service descriptions; and implementing commercial quality security do not really fix the problem. An SLA can be violated (including intentionally); securing the transmission and controlling access does not prevent data being revealed through other channels and semantically described services may still be misleading. So the decision to collaborate is still based on an analysis of the risks versus trust in the service provider.

In some scenarios the trust is based on the obvious common interest of all participating parties in the VO, in others only penalties described in the SLAs provide the confidence that a provider will do its best not to violate the agreements. The SLA might also place constraints on how data must be treated.

This problem has nothing to do with the virtualization of resources, as it should not be seen on this level. The fact that one or more of the service providers may build on top of a cloud infrastructure does not matter. But are current SaaS models ready to support such scenarios?

A frequently mentioned problem of clouds is the lack of appropriate SLAs providing confidence in the provider. I do not think that this is a problem in general. Depending on what you want to be done externally, one needs to make an analysis of risks versus benefits, and for many cases – in particular if the providers are easily replaceable or if no real-time constraints leads to an overall failure in case of a delay – the implied SLA (Quality: Best effort, Penalty: No payment on failure) is sufficient. A typical approach used in Grid solutions is to have local resources and remote resources with standardized interfaces, thus making providers replaceable. This approach can also be applied to clouds (e.g. OpenNebula + Amazon EC2). In my view, the major aspects not addressed by cloud solutions are real collaboration scenarios beyond a consumer and provider relationship. Cloud approaches either provide a virtualized infrastructure or deliver Software (or “Everything”) as a Service (SaaS). The scenarios considered in Business Experiments in Grid always have more than two clear stakeholders in the scenario. In order to realize such scenarios the Cloud/SaaS provider might be part of such a Virtual Organisation, but this would need infrastructure for VO Set-up, potential quick replacement of providers in case of failures and so on, very similar to that found in current Grid technology. So, for this aspect, our hypothetical cloud version of BEinGRID is now more like: Business Experiments in Grids partially delivered by Clouds!

The problems found in many discussions about clouds (e.g. look at Above the clouds) apply in a similar way to collaborative business Grids as realized in many past, or ongoing, service-oriented Grid projects such as BEinGRID, BREIN, IRMOS, NextGrid or Akogrimo. I think combining both worlds using virtualization approaches for the provision of services and aiming for the delivery of complete solutions in a SaaS/XaaS model using clouds with a standardized interface could contribute to the reliability of provided services. The cloud could provide parts of the VO Management elements, such as Creation of Instances on Distributed Hosting Environments as identified on Gridipedia. However, in this case, cloud is not a replacement of Grids, but a replacement of how certain services within a Virtual Organization are provided. The Grid is dead? No! But as Virtual Organizations delivering a collaborative business scenario are far more complex compared to outsourcing scenarios, they are – as of now – mostly used in business to business scenarios and need to justify the increased effort.

So in conclusion, our Business Experiments in Clouds is fine if it is more a client-server relationship we are considering, but in truth we need a Business Experiments in Grids (maybe partially delivered using the cloud) if the target is a collaborative scenario involving many business partners in a non-hierarchical relationship. So, the question is not “Clouds or Grids?” but “How to integrate Grids and Clouds?”.

Notes

*See for example : http://cloudcomputing.sys-con.com/node/771947 and http://www.faz.net/[...]

Tags: Grids and Clouds

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