Node.js with Vagrant and Chef@ Benetech

April 24, 2014

Chris Bumgardner

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.

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

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.

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.

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.

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.

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.

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

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

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.

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.

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

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.

Thanks!

Chris Bumgardner

https://github.com/cbumgard

https://www.linkedin.com/in/chrisbumgardner

Please don’t hesitate to contact me

Links

This presentation: https://www.dropbox.com/s/v1v6no0i98uiuwc/Benetech-Nodejs-Vagrant.pptx

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/