Setting up a virtual machine, using VirtualBox and Vagrant

If you are deploying your Yesod app on a remote webserver that is a different platform than your working machine (most of the time it is), it is necessary to build on a virtual machine that matches the webserver environment.

For example, if you deploy to Heroku you need to compile on a Linux 64-bit with Ubuntu 10.04.

This guide provides instructions in creating a virtual machine for Heroku deployments.

Installation

1. Download VirtualBox from Oracle. VirtualBox is a general-purpose full virtualizer for x86 hardware. Targeted at server, desktop and embedded use, it is a professional-quality virtualization solution that is also open source software. VirtualBox runs on Windows, Mac OS X, Linux, and Solaris.
2. Download Vagrant. Vagrant has excellent support documentation (but watch out for the vagrant destroy command, you'll have to redo everything).
3. Get the [https://bitbucket.org/puffnfresh/vagrant-haskell-heroku](vagrant-haskell-heroku box project on Bitbucket) (create an account to download it). This lucid64 box contains automated download+install "recipes" for the Haskell Platform and Heroku Toolbelt.
   • Update the configuration file Vagrantfile so it contains :ghc_version => '7.4.2'.
   • Do vagrant up - this will download all required packages and takes a looooooooong time.
   • Do vagrant ssh. You are now in Linux Ubuntu in the home folder.
4. Once you are inside the box, install additional tools and packages:
   • Do sudo apt-get update to update the package list.
   • Do sudo apt-get upgrade to update installed packages.
   • sudo apt-get install git-core
   • If you prefer vim above vi: sudo apt-get install vim
   • Getting the right Postgresql is explained in a separate wiki page.
5. In The VirtualBox app you can set shared folders. I put the Yesod project in the shared folder, so I can access it from my working machine as well. The path from Linux is /vagrant/<project name>/.
6. Cabal and Yesod:
   • Do cabal update and inside the Yesod project folder cabal install.
   • Yesod is not automatically recognized. At the end of ~/.profile write PATH="$HOME/.cabal/bin:$PATH".
   • yesod devel will not yet work because Postgresql still needs to be installed and configured. That instruction page needs to be written.

Viewing yesod devel in the browser

• To compile from Linux and see the result on my working machine, I use the network setting NAT (see VirtualBox > Settings > Network).
• Edit the file Vagrantfile in the shared folder and add the line: config.vm.network :bridged.
• Do vagrant reload. At "Available bridged network interfaces" choose either Ethernet or Wi-Fi.
• Then do ifconfig from Linux, at the first item (eth0) grab the IP at inet addr. 
• Run yesod devel, enter the IP in a browser and add the port :3000.

Troubleshooting

Occasionally I get the error "SSH connection was refused!". See http://vagrant.wikia.com/wiki/Usage for a solution.