Friday, 29 May 2009

Cloud Multiplicity - the multi-cloud

Reading a great book by George Reese, Cloud Application Architectures - O'Reilly 2009. Clearly a guy with real experience of the cloud as the founder of Valtira and latterly enStratus ( a competitor to RightScale. )

Whats an eye opener is the perspectivies of reliability of virtual instances versus physical instances. He is quite direct in his statements that virtual instances are much less reliable than physical instances. While its a AWS perspective he states that EC2 instances are much less reliable and that design for failure is a critical step in cloud design. He advocates as I do a strong separation of presentation, business modeling, business logic, and data as per the MVC paradigm and is realistic in the focus on cluster technology in application and database server scaling design for cloud elasticity benefits.

He also has some useful definitions of security around the Network intrusion and Host intrusion Tools which are clearly a key enabler for Cloud services as he points out that physical network DMZs are not possible in many externalized cloud data centers. I like also his refreshing real world view of security evolution in standards lagging in the virtualizational separation that means that separate server partitioning is a false situation in logicalization of servers via VMs.

He provides a wake up call on the I/O performance of storage which is often not suitable for NR or real time applications and squarely in the batch temporal domain of service performance which places cloud as backup as a service and archive. Perhaps AWS recent view of accelerated network I/O services is a recognition of this and that network based cloud services and strategic alliances is a critical strategy for cloud performance.

The book also illustrates the performance issues over CPU intensive operations in the cloud and also the barriers of legacy investments to cloud adoption of IaaS (He also confirms its cheapers to extend the existing infrastructure) but confirms the loss of future strategy by these challenges. (as ratified with his conversations with James Urquhart;txt ) The ability to adopt different VM strategies for legacy apps modernizations will be a key driver to cloud integration which I see as being able to work at different levels of abstraction rather than just at the IaaS and PaaS tiers. Taking a classical orchestrator view of modernization and adoption will fail as it seeks to control IT estate too much whereas a multiple use case approach to on-demand services underpined by a range of evolving platforms for IaaS and PaaS will accelerate adoption.

I believe the emergence of multiplicity strategies to support statistical multiplexing patterns will drive realistic cloud adoption including virtualization patterns in :
  • Partitioning strategies for worloads to cloud operations
  • Clone strategies for backup, replication, intelligence extensions e.g. RT language translation and multiple process services for multiple parallel temporial services
  • Applicance strategies for application extentions via API
  • PaaS and IaaS integration e.g. GoogleApps and integration
  • Adoption of mainstream Service Management challenges with Social media systems e.g. the Twitter / Facebook as a "remedy channel" effect
The advocacy of using PaaS investments to support operational I/O and CPU performance will create the tipping point to develop PaaS and SaaS services. The security of public clouds do still have partitioning problems for geographic and national law compliance but as explained in the book the technical aspects are not impossible to replicate to bring the security to a level of a private data center in may respects.

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