Cloud computing is a paradigm shift from traditional computing. This means dropping existing applications in the cloud without any changes won’t always work. The architecture is similar but it is different enough that one needs to, at a minimum, plan the transition. Some PaaS providers make this easier than others. Using standard and open interfaces helps. This chapter describes these changes and how to go about planning for them.
Not having to manage the infrastructure layer also means there is little control over it. Firewalls are a good example here. Most PaaS providers don’t offer traditional firewall configurations. Instead some may require the developer to put IP restrictions into their code or possibly via something like Apache’s .htaccess files which has the ability to allow and deny from specific IP addresses. Some PaaS providers do not support this.
Networking in the cloud is an interesting topic. For general purpose computing, most users won’t notice a difference. Especially if they’re just sticking with PaaS providers in a default non-redundant geographic location. There are three primary concerns when dealing with networking in the cloud.
Plan for failure. This is a good idea even in traditional computing but as complexity increases so will volatility.
Remember the underlying infrastructure is shared. Bandwidth may be spiky. Plan accordingly.
The amount of time it takes for a request to send and have the response come back ...