Cloud Services For Supporting an Application’S Initial Deployment and Runtime Migration |
The cloudcomputing paradigm has achieved widespread adoption in recent years. Itssuccess is due largely to customers’ ability to use services on demand with apay-as-you go pricing model, which has proved convenient in many respects. Lowcosts and high flexibility make migrating to the cloud compelling. Despite itsobvious advantages, however, many companies hesitate to “move to the cloud,”mainly because of concerns related to service availability, data lock-in, andlegal uncertainties.1 Lock in is particularly problematic. For one thing, eventhough public cloud availability is generally high, outages still occur.2Businesses locked into such a cloud are essentially at a standstill until thecloud is back online. Moreover, public cloud providers generally don’tguarantee particular service level agreements (SLAs)3 — that is, businesseslocked into a cloud have no guarantees that it will continue to provide therequired quality of service (QoS). Finally, most public cloud providers’ termsof service let that provider unilaterally change pricing at any time. Hence, abusiness locked into a cloud has no mid- or long term control over its own ITcosts. At the core of all these problems, we can identify a need for businessesto permanently monitor the cloud they’re using and be able to rapidly “changehorses” — that is, migrate to a different cloud if they discover problems or iftheir estimates predict future issues.