PaaS providers often have several minor requirements in order to function properly. This means a pre-built application might not automatically work when uploaded to PaaS. Common issues are:
Hard coded paths
Incorrect library dirs
Missing libraries and drivers
Many of these issues can be properly addressed in forums, knowledge bases or documentation. There should also be “hello world” type applications and examples to work from.
Remember, free offerings from providers are there for people to try it before they buy it. Production level support and features won’t typically be at the free level. Additionally, features commonly relied on like scheduled jobs, memcached, databases, and so on may require additional cost from the start.
Almost all PaaS providers also have client tools of some kind. Expect to download and install them. Remember though, PaaS is supposed to make life easier.
When sitting down to write code, pay close attention to resource usage. In a PaaS environment it’s important to pay attention to an individual instance footprint. Different providers call them different things, but an application cannot simply grow in memory forever on a single request. That’s not how most PaaS offerings work. There are methods of doing this sort of high memory work but this isn’t the typical use case for PaaS.
These limits vary from provider to provider. Some have soft limits which an app can grow beyond for a short time, but all have a hard limit that at some point will ...