To succeed with public cloud, you must make sure you have the right performance data to keep your vendor accountable. By monitoring key applications end-to-end, you will be able to key real-time SLAs on-premise and off. Therefore, enabling you to succeed with your public cloud provider:
Ultimately, you want your cloud provider to be a full partner in supporting your cloud services whether IaaS, PaaS, or SaaS. You want them to not only practice good security measures but also be able to get to the root of the problem quickly, however at this time do not count on them to solve every problem. For IaaS, the support folks are generalists, for SaaS they are specialists, and PaaS is a mixture of both. However, they keep the hardware running and in many cases that is more than enough work, leaving the application or data to you.
You can read more here: Public Cloud Reality: Support Responsibility