Scalr is software that auto-scales web applications by provisioning and configuring resources like servers, storage, and IP addresses. These resources are taken from the cloud, like EC2 and now Rackspace Cloud.
When we started Scalr, all we wanted it to do was provide auto-scaling on EC2. This was to be done in simple form: load goes up, add more servers. Load goes down, remove a few.
But then we discovered that there was more to auto-scaling than just adding more servers of the same type. We needed to make sure that load was balanced properly. That no server termination caused users to be cut off. That dysfunctional servers were replaced. That servers were always kept 55 minutes into the hour. And for databases, that data was replicated between nodes.
We also discovered that an intuitive, fast UI was important for our users to get their job done. Same for our hosted DNS. Same for our service config tool. And as we make Scalr the best auto-scaling platform out there, people have knocked on our door asking for us to add auto-scaling to Rackspace Cloud. Over, and over, again. So we did.
Let me say that Rackspace Cloud is a great home to any web app. Not only is it close to feature parity with EC2, it also has some useful abilities of its own, like server Resizing. Server resizing is great for a particular use case: scaling your master database to handle more write transactions. This avoids all sorts of brittle fancywork, and provides a simple solution to the single largest bottleneck in web apps today.
You also get Fanatical Support, the fitting name Rackspace gives to its support team. This is very useful when using Cloud infrastructure for the first time.
Oh, and by the way; since we started working on supporting Rackspace Cloud, we’ve joined OpenStack under the sexy name openstack-platform-php. Yay!