Reliability does not come from SOA Governance
An interesting InformationWeek article asks whether SOA intermediaries such as "enterprise service bus, design-time governance, runtime management, and XML security gateways" are required for an effective SOA. It further posits that SOA governance is a must for any successful SOA initiative.
As usual, the report (offered free courtesy of IBM), focuses on SOA infrastructure that while certainly fitting into the categories of SOA intermediary and governance does very little to assure stability and reliability of those rich Internet applications and composite mashups being built atop the corporate SOA.
Effective SOA Requires Intermediaries via InformationWeekIn addition to attracting new customers with innovative capabilities, it's equally important for businesses to offer stable, trusted services that are capable of delivering the high quality of service that users now demand. Without IT governance, the Web-oriented world of rich Internet applications and composite mashups can easily become unstable and unreliable. To improve your chances for success, establish discipline through a strong IT governance program where quality of service, security, and management issues are of equal importance.
As is often the case, application delivery infrastructure is relegated to "cloud" status; it's depicted as a cloud within the SOA or network and obscured, as though it has very little to do with the successful delivery of services and applications. Application delivery infrastructure is treated on par with layer 2-3 network infrastructure: dumb boxes whose functionality and features have little to do with application development, deployment, or delivery and is therefore beneath the notice of architects and developers alike.
SOA intermediaries, while certainly a foundational aspect of a strong, reliable SOA infrastructure, are only part of the story.
Reliability of services can't be truly offered by SOA intermediaries nor can they be provided by traditional layer 2-3 (switches, routers, hubs) network infrastructure. A dumb load-balancer cannot optimize inter-service communication to ensure higher capacity (availability and reliability) and better performance. A traditional layer 2/3 switch cannot inspect XML/SOAP/JSON messages and intelligently direct those messages to the appropriate ESB or service pool.
But neither can SOA intermediaries provide reliability and stability of services. Like ESB load-balancing and availability services, SOA intermediaries are largely incapable of ensuring the reliable delivery of SOA applications and services because their tasks are focused on runtime governance (authentication, authorization, monitoring, content based routing) and their load-balancing and network-focused delivery capabilities are largely on par with that of traditional l2-3 network infrastructure.
High-availability and failover functionality is rudimentary at best in SOA intermediaries. The author mentions convergence and consolidation of the SOA intermediary market, but that same market has yet to see the issue of performance and reliability truly addressed by any SOA intermediary. Optimization and acceleration services, available to web applications for many years, have yet to be offered to SOA by these intermediaries. That's perfectly acceptable, because it's not their responsibility.
When it comes to increasing capacity of services, ensuring quality of service, and intelligently managing the distribution of requests the answer is not a SOA intermediary or a traditional load-balancer; that requires an application delivery network with an application fluent application delivery controller at its core.
The marriage of Web 2.0 and SOA has crossed the threshold. It's reality. SOA intermediaries are not designed with the capacity and reliability needs of a large-scale Web 2.0 (or any other web-based) application. That chore is left to the "network cloud" in which application delivery currently resides.
But it should be its own "cloud", it's own distinct part of the overall architecture. And it ought to be considered as part of the process rather than an afterthought.
SOA governance solutions can do very little to improve the capacity, reliability, and performance of SOA and applications built atop that SOA. A successful SOA depends on more than governance and SOA intermediaries; it depends on a well-designed architecture that necessarily includes consideration for the reliability, scalability, and security of both services and the applications - Web 2.0 or otherwise - that will take advantage of those services.
That means incorporating an intelligent, dynamic application delivery infrastructure into your SOA before reliability becomes a problem.
