Phusion Blog

On Unix systems, compiling software to install it is often the norm. However compiling takes CPU time and memory, and on some systems it is preferable not to have a compiler installed for security reasons. Especially compiling C++ code is memory-intensive, and could require as much as 700 MB of RAM. Since Phusion Passenger is written largely in C++, the need to compile Phusion Passenger could be problematic for some users, e.g. users on small VPSes with little memory.

Another problem is the need to compile Nginx. Unlike Apache, Nginx does not support dynamically loadable modules. So to add Phusion Passenger support, Nginx must be recompiled. Some users do not like doing this.

Today’s solutions

There are some solutions for this problem that you can already use with the current version of Phusion Passenger:

1. You can use our Debian and Ubuntu packages, kindly contributed by John Leach from Brightbox. John Leach has been helping us with Debian packaging for years now, and he often updates his packages within a few days after an official release. Packages for both the Apache mode and the Nginx mode of Phusion Passenger are available.
   

   If you didn’t already know about this, you should. Strongly recommended. It solves nearly every problem users have with installing Phusion Passenger. Just run apt-get install libapache2-mod-passenger or apt-get install nginx-full, and you’re done. The provided Nginx package is the exact same as the one in Debian/Ubuntu, but with Phusion Passenger support added. This means you get to keep your /etc/init.d/nginx init script and other nice things.

   There are just two drawbacks at the moment: Phusion Passenger Standalone (described later in this article) is not packaged, and Phusion Passenger Enterprise is not packaged.

2. You can precompile Phusion Passenger on one of your machines, and copy over the binaries to another machine.
3. Users who do not mind compiling Phusion Passenger but do mind compiling Nginx, can use a reverse proxy setup with Phusion Passenger Standalone.

Tomorrow’s solution: binaries for Phusion Passenger Standalone

While the current Debian packages are great, we haven’t been standing still. There is still room for improvement. One of the things that we’ve been working on is a generic binary building infrastructure for Phusion Passenger. The end goal is to eliminate the need to compile Phusion Passenger, for all users that are using Linux on the x86 and x86_64 architectures, regardless of the distribution that they’re using.

This infrastructure automatically builds generic, multi-distribution-compatible Linux binaries for x86 and x86_64 every time we push commits to our Git repository. The Phusion Passenger installers can then just download binaries from the Phusion server instead of compiling them from source. The installers automatically check whether the downloaded binaries work on the current system, and if not, falls back to compiling. For 95%-99% of the users, this system effectively eliminates the need to compile Phusion Passenger. Furthermore, this infrastructure compiles binaries for both the open source variant and the Enterprise variant.

Rome was not built in one day, so we’re tackling this problem iteratively. Starting from the next version of Phusion Passenger, these automatically built binaries will be used in Phusion Passenger Standalone.

What is Phusion Passenger Standalone, and how is it related to compiling?

For those of you who are not familiar with Phusion Passenger Standalone: it is a third mode of Phusion Passenger, alongside with the Apache mode and the Nginx mode, introduced in 2010. In Standalone mode, Phusion Passenger does not require an external web server, and can be started with just a single command: passenger start. This command starts a fully-featured Phusion Passenger instance. In fact, it is powered by an Nginx core, making it very fast and lightweight, and extremely good at serving static assets. You can even expose Phusion Passenger Standalone immediately on the public Internet without using a reverse proxy, something e.g. Unicorn cannot safely do (“Slow Clients Are Problematic”). Therefore, Phusion Passenger Standalone is the easiest way to get a Ruby web app up and running with minimal hassle and with great performance. It can also be installed in a reverse proxy setup behind Nginx, for those who do not want to or cannot compile Nginx.

The following video, originally created in 2010, demonstrates Phusion Passenger Standalone. Note that back then it was still called “Phusion Passenger Lite”. As you can see, Phusion Passenger Standalone compiles its own runtime when it is run for the first time. Compiling can take a few minutes. Starting from the next version, starting Phusion Passenger Standalone for the first time takes a few seconds.

Day after tomorrow’s solutions: fully-automated binary building and package building

We have two goals for the futher future:

1. Automatically download binaries when installing Phusion Passenger for Apache and Phusion Passenger for Nginx.
2. To fully automate the building of Debian packages. Although the generic binaries should work for most of our users, installing Debian packages is easier still, and integrates better with the OS. We’re working on a system that will publish 100% working Debian packages 15 minutes after we publish the source code for a new release, so that no human intervention is required to publish Debian packages. This will greatly increase ease of installation and upgrade for users. There will also be automatically built Debian packages for Enterprise customers.

   We’ve already begun working on integrating Debian packaging scripts into our main Git repository. We’ve also written an automated set of tests for checking whether packages built with these scripts work correctly. These tests are run by our continuous integration server on every commit, so you could say that we’re employing “continuous packaging”.

Conclusion

We’re working hard on making Phusion Passenger as easy to install as possible. We take usability very seriously, and we invite everyone to review our generic binary building system, our Debian packaging scripts, as well as our packaging tests. All code is open source and available on Github.

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