We have been running our PHP applications on CentOS \ MySQL dedicated servers for sometime.
However, I now have a requirement from a client that we are highly fault tolerant and able to scale up quickly and easily.
What is involved in migrating from a dedicated Linux server environment to cloud based technology? Is it a steep learning curve or are most of the differences under the hood.
You can easily take your PHP application to cloud by creating your own PaaS. Apache Stratos is a PaaS framework which allows you to do so. It has out of the box support for PHP and MySQL (those are called cartridges). It guarantees high availability and autoscaling support and also load balancing. You dont need to change your application code either.