1. Node.js with Vagrant and Chef
@ Benetech
April 24, 2014
Chris Bumgardner

2. Why Vagrant?
 Speed and Portability
 Get a working uniform development environment
running in about 15 minutes while getting a coffee.
 This often takes hours or days for a modern environment
getting specific libraries, tools, and versions for a specific
operating system.
 Open source and mature. Around since 2010.

3. Advantages to a VM Image
 Vagrant is small: just text files in source control
 A snapshot is typically around 0.5GB – 1GB. Hard to host and
transfer.
 A snapshot is binary: changing a version of a library is hard,
but in Vagrant it is just a configuration change.
 Abstraction: Vagrant can run on top of different providers,
such as AWS, Docker or Azure in addition to a local virtual
machine.
 https://github.com/mitchellh/vagrant-aws
 https://github.com/10thmagnitude/vagrant-azure

4. Installing Vagrant & VirtualBox
 Install Vagrant here:
http://www.vagrantup.com/downloads.html
 Install VirtualBox here:
https://www.virtualbox.org/wiki/Downloads
 Cloud boxes are automatically downloaded and
installed with Vagrant 1.5+
 Be sure to upgrade Vagrant if you have an older version.

5. Configuration Management via Chef
 Idempotent
 You can run Chef multiple times on the same system with
identical results.
 Not the case with shell scripts: running more than once will
usually lead to unpredictable results.
 Cross-platform
 Chef supports Linux, Mac, Windows
 Shell scripts are system dependent
 Existing ecosystem of cookbooks: don’t reinvent the wheel.
 Chef Solo: runs on local machine, does not require server
infrastructure.

6. Docker, Packer, etc: More DevOps
 DevOps tools appear daily.
 Chef alternatives: Puppet, Ansible, Salt, etc.
 Docker.io
 Promising tool that contains and virtualizes processes.
 Think of Vagrant but for a specific process.
 Example: turn a server application into a portable image.
 Packer.io
 Automates creation of machine images.
 A meta layer above a tool like Vagrant.

7. Mathoid using Vagrant
 https://github.com/cbumgard/mathoid-vagrant
 Once running you can access at localhost:10042
 Built on Ubuntu Precise 12.04 64-bit base box. Found 14.04
not compatible yet with Mathoid.
 First time you “vagrant up” it has to download the base
box (~300MB). Boxes are cached locally however.
 Added Chef cookbooks as Git submodules. Requires just
an extra two commands the first time you clone the repo,
makes for a cleaner repository.

8. Mathoid + Vagrant continued
 All configuration done in the Vagrantfile:
https://github.com/cbumgard/mathoid-
vagrant/blob/master/Vagrantfile
 Non-provisioning changes to Vagrantfile, such as
networking configuration, will take effect on a “vagrant
reload” (halt + up).
 Provisioning changes will not run unless you destroy and
re-up, or do a “vagrant provision”.
 This Vagrantfile is a combination of shell, file, and chef
provisioning.

9. Vagrant: Things to Note
 Pick your base box carefully.
 Ideally has the configuration manager (e.g. Chef) installed that you will
use for provisioning.
 Avoid anything else if possible. For example a base box with Node.js built
in will be trickier to upgrade to a new version than if you add Node.js as
a Chef cookbook.
 You can always see installed boxes via “vagrant box list”
 When creating a Vagrantfile test incrementally via “vagrant
provision”
 Vagrant commands you should learn:
 init, up, ssh, suspend, resume, halt, destroy
 reload: halt + up

10. Vagrant: continued
 When switching networks on the host (e.g. changing WIFI
networks on your laptop) you may need to “vagrant reload”
for the guest VM networking.
 If you want to access files from your host machine inside the
guest vm, be sure to use NFS:true in your synchronized folder
setup.
 Gives ~10x performance accessing files. Noticeable if running a
webserver like Node.js in the VM on files on your host.
 Requires nfs-common installed.
 Requires password on “vagrant up”. Fix for that at:
https://gist.github.com/GUI/2864683

11. Vagrant: continued
 When shell provisioning keep in mind:
 Your script is running as root. No need for sudo.
 Interactive prompts will hang and timeout. Make sure to add
flags like “-y” to command-line calls like “apt-get”.
 You can enable a GUI from the Vagrantfile if you want to do
graphical work in the VM
 Provisioning usually requires download files from many
sources: occasionally there will be intermitent problems
downloading from certain sources.
 Check out Vagrant Shares. New in 1.5. Allows giving others
outside your local network access to your running machine.

12. Node.js: Lessons Learned
 Node.js runs all Javascript code on a single thread.
 So you can’t do heavy operations in the JS layer.
 Consider message queues or pub/sub like Redis.io
 Thinking asynchronously takes getting used to. Learn libraries
like async at the start: https://github.com/caolan/async.
 Flow control is very important.
 Also greatly helps exception handling.
 Control your versioning carefully for dependencies.
 Follow semantic versioning: http://semver.org/.
 If your versioning isn’t specific enough a deployment can break.
 Often best to package dependencies during deployment.

13. Node.js: Lessons Continued
 Amazing ecosystem: always check for an existing npm
module before writing something new.
 I strongly recommend Grunt for building your project, and
Bower for client-side web package management.
 http://gruntjs.com/
 http://bower.io/
 Yeoman generators are a great way to bootstrap a project:
http://yeoman.io/
 Daemonize your app with tools like forever:
https://github.com/nodejitsu/forever

14. Node.js: Lessons Continued
 Use clustering module: will run a copy of your Node
process on each available core.
 Think stateless: in general for web apps, and especially
here so you can scale out.
 Follow CommonJS module for code organization:
http://www.commonjs.org/specs/modules/1.0/
 Don’t expect to share a lot of code between the browser
and the server. However the lack of context switching (all
JS all the time) is the real benefit.

15. Thanks!
 Chris Bumgardner
 https://github.com/cbumgard
 https://www.linkedin.com/in/chrisbumgardner
 Please don’t hesitate to contact me 

16. Links
 http://www.slideshare.net/chrisbumgardner/benetech-nodejsvagrant
 https://github.com/cbumgard/mathoid-vagrant
 http://www.vagrantup.com/downloads.html
 https://www.virtualbox.org/wiki/Downloads
 https://github.com/mitchellh/vagrant-aws
 https://github.com/10thmagnitude/vagrant-azure
 https://gist.github.com/GUI/2864683
 https://github.com/caolan/async
 http://semver.org/