Although the term, SLA has already been mentioned, the first question is what is an SLA? Although there are several answers (any infrastructure architect among you can confirm that), I would like to confine myself to the following simple answer:

An SLA is a contract between you and your cloud service provider that guarantees you a certain degree of availability for services booked. That sounds very good, but in real life that just means that you get your money back if the guarantee is not respected.

Nevertheless, we should now pursue the question: how do I determine a degree of availability? For the degree of availability, we first need the desired uptime. This can vary according to your needs. For example, if you operate a webshop, the targeted uptime is 24 hours x 7 days or 168 hours per week or 8,760 hours per year. But if you only have one application for the daily work in your company, the desired uptime can be limited to a core time, for example, 100 hours per week or 5,200 hours...