Pros and cons of External Cloud Services

Nowadays, the cloud is everywhere. All software you see and all providers propose cloud brokering via their Datacenters, platforms or software. Now what are the real cloud drivers? We often speak about cloud acceleration but rarely speak about issues that arise when you start playing in the cloud...

The good points with the cloud :

• It is fast and flexible (from a service ramp up / down perspective)
• It usually implements the very latest technology and software platforms
• It is usually very adapted to geographically dispersed solutions, allowing resilience and regional / local implementation of global solutions across the globe
• You don't have to handle capacity reporting and planning of the environment... just pay as you go
• For some very specific requirements, you can have your environment online only a few hours per day (when you really need it). The rest of the time, you turn it off and limit the cost, which is not as cost efficient when done on your owned assets
• You run on a standard operated environment
• There is a huge varitery of services (IaaS, PaaS, SaaS) to subscribe out there. Cloud solutions are usually financial efficient when you buy PaaS or Saas. IaaS will usually let you manage a level of complexity between your in-house architecture and the cloud infrastructure which adds complexity and overhead to your teams

Now the drawbacks of these kind of services : 

• As soon as you have a certain volume and a sustained growth, public cloud is usually more expensive that in house
• If you don't run on standard "off the shelf" applications, the cloud can be a real issue for you. Even though upgrades are planned and predictable, there is no place for blocking upgrades of versions. Should your application not support that intense patching roadmap, you will be really bothered
• Service transfer from cloud services can be a real pain point. A very simple example I went through was when using an SAP on an "as a service" mode. When attempting to exit that service, and without any clear contractual statement, I was explained that the SAP image itself was the intellectual property of the vendor. As a result, a complete replatforming of the SAP environment had to be done, follow by a data synchronization.
• Data reversibility is an extension of the issue above. Be sure, when contracting a cloud service, that you have the right conditions for a transition out. Vendor "lock in" is one of the most common issues on the cloud. 
• Most cloud services come with limited to no SLA. Cloud providers prever to commit on means than results. Be aware of this before putting any critical service in the cloud
• Cloud is usually not recommended for critical data. Indeed, it is always complicated to impose data location to cloud providers. Moreover, cloud providers are usually seen as a big regulartory risk since the staff managing the cloud platforms is geographically dispersed and you usually have no control over this

Cloud services continue to progress and seduce more and more companies. They remain perfect for either temporary workload hosting (IaaS) or complete end to end solution hosting (PaaS or SaaS, where limited integration is required with your core company services. 

Keep in mind that cloud services are extremely standardized but always come with limited SLA commitment and a very limited framework. As such, either you will need to be a major player to get an appropriate contract or you will have to accept the risks on the services you contract.

To conclude: should you have a sustained growth, internal private cloud with capacity on demand will be the perfect solution. For other cases, or off the shelf platforms, hybrid or public cloud can greatly enhance your capabilities but keep in mind that getting strong commitment on SLAs and legal / auditability aspects will remain a challenge for you.