The company started out as PHPfog, which GigaOM’s Derrick Harris characterized two years ago as a sort of Heroku for PHP developers, but changed focus to support multiple languages and multiple public clouds.

The developers using PHPFog probably already know it’s not  easy to migrate from one software version to another and when the software in question is actually the platform which runs your applications, things get really hairy. One AppFog user acknowledged that the company provided notice and guidance about migrating applications but said any such migration is fraught. “Infrastructure moves are incredibly difficult and risky and the upside is usually fairly slim,” he said via email.

We'd love to keep in touch… so please follow @AppFog as we wind down here…. It's been freaking awesome.—
PHP Fog (@phpfog) January 23, 2013

The problem of a defunct PaaS may be rare — Coghead disappeared in 2009, although SAP ended up buying the intellectual property. But given that PaaSes act as platforms for real applications, customers need to go into deployment with their eyes wide open.

Gartner distinguished analyst Yefim Natiz, who studies this topic, recommends that PaaS customers negotiate terms to mitigate risk. “You should put something in your provisions that if the company is acquired or goes away, you can get some money back — even if a company goes bankrupt there are assets left over. The best thing is to get your code in escrow so if the PaaS goes away you can run it on premises if you need to,” he said.

And of course, all companies should always back up their underlying data all the time.

Carlson, who provided the tweetstream below to show how some customers “evolved” their thinking about the transition, said the benefits of moving to AppFog outweigh the headaches of the move itself.

“They get much better service, a choice of infrastructure, new languages, five new database services and can choose whatever version control system they want to manage their code instead of being forced into Git,” he said in an interview.

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The new option, available from AppFog’s site, costs $50 per user for 500MB to 4GB of database storage and 50GB of data transfer. In July, Portland, Ore.-based AppFog launched its ambitious cross-cloud PaaS effort including a free  version for up to 2GB of RAM. Additional monthly plans with more memory started at $100 for 4G, $380 for 16GB and $720 for 32GB. The free version is still available.

Each MySQL and PostgreSQL database instance comes with 500MB of storage; each Redis and RabbitMQ instance comes with 10MB of RAM and 6 concurrent connections; free custom domains and the fastest servers from whichever cloud infrastructure the developer selects.

AppFog CEO Lucas Carlson said he made the move in response to developers who want more storage and other resources.  ”When developers told me that our plans were not quite right for their needs I knew i had to make it better,” Carlson said via email.

The problem with PaaS is that while developers love the freedom to design and develop on that infrastructure, many companies still don’t want to deploy on an outside platform. Another issue is VMware’s decision to spin off Cloud Foundry to a new corporate entity. That has sparked concern about how open the Cloud Foundry development process will be going forward. VMware and parent company EMC have said they won’t discuss details of its spinoff plans until early next year, leaving Cloud Foundry-dependent PaaSes in a bit of a quandary.

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To add more transparency, Cloud Foundry is now offering now offering an application to help customers check out what features and services are available from any public CloudFoundry endpoint.

 Cloud Foundry Core, which went live Tuesday morning “will give you a real-time glimpse of what any Cloud Foundry endpoint will support,” said James Watters, director of ecosystem development for Cloud Foundry

According to the web site:

To promote cloud portability across different instances of Cloud Foundry, Cloud Foundry Core defines a baseline of common capabilities for different Cloud Foundry instances. Further, it provides an open mechanism that lets anyone instantly validate and confirm the specific frameworks and applications supported by a particular instance of Cloud Foundry and whether it supports Cloud Foundry Core.

Lucas Carlson, CEO of AppFog, which now claims 100,000 applications running on its PaaS, is bullish on the new app, calling it “a step forward in PaaS transparency, proving interoperability can exist and giving enterprises more comfort in taking the leap to PaaS.”

Carlson says business PaaS adoption will remain stalled until customers can be assured that their applications can be moved from platform to platform as needed.

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Company CEO Lucas Carlson said the deal — terms of which were not disclosed — will give the company deeper and broader Node.js support and access to more Node.js developers.

“Nodester has one of the biggest communities Node programmers and Node.js was the fastest growing language on Appfog” he said in an interview. Node. js is a server-side, event-driven programming language popular among developers writing web applications.

For Portland, OR-based Appfog, it’s all about aggregating those developers — whether they code in PHP, Java, Node.js or what-have-you — and making it easier for them to run their applications on any cloud infrastructure.

Carlson says Appfog’s secret sauce is its ability to let you take a given application that’s running on Amazon and move it to HP’s cloud or vice versa with the click of a button. That is a company’s first line of defense against cloud lock-in, Carlson likes to say.  (Although clearly, you would have to lock in using Appfog’s PaaS to do that, but I quibble.)

In 2010, Appfog started out as PHP-focused PHP Fog but has since morphed into a “polyglot” PaaS that supports Ruby, Java, Node.js — about 12 frameworks in all. Next up? Java Enterprise Edition (J2EE), Go and Perl languages.

The problem with PaaS is that too many companies still see them as too expensive and as a possible source of vendor lock-in, Carlson said. His pitch is that developers can write and run their applications on Appfog for less than they would pay to run them on something like Amazon or Rackspace’s infrastructure alone.

As GigaOM reported in July, Appfog sets prices based on RAM alone and anything up to 2 GB of RAM is free. There are monthly plans for 4 GB, 16 GB and 32 GB for additional charges which include all the underlying infrastructure fees and for which Appfog bills the customer. That’s pretty good account control.  Then, if the company wants to move from one set of infrastructure to another it can do so, provided Appfog remains the intermediary.

Appfog, which itself builds atop Cloud Foundry APIs, competes with Heroku, Engine Yard and other PaaSes. This acquisition could be a sign of more PaaS consolidation to come.

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