Sunzi

"The supreme art of war is to subdue the enemy without fighting." - Sunzi

Sunzi is the easiest configuration automation and infrastructure as code utility designed for mere mortals.

If Chef, Puppet, Ansible or SaltStack is driving you nuts, try Sunzi!

Sunzi assumes that modern Linux distributions have (mostly) sane defaults and great package managers.

Its design goals are:

• It’s just shell script. No clunky Ruby DSL involved. Most of the information about server configuration on the web is written in shell commands. Just copy-paste them, rather than translate it into an arbitrary DSL. Also, Bash is the greatest common denominator on minimum Linux installs.

• Minimal diff from default. No big-bang overwriting. Append or replace the smallest possible piece of data in a config file. Loads of custom configurations make it difficult to reason what you are really doing.

• Minimum dependencies. No configuration server required. You don’t even need a Ruby runtime on the remote server, sunzi runs a combined shell script over SSH.

See also:

• sunzi-vps - Interactive server provisioning plugin for Linode and DigitalOcean.
• sunzi-recipes - Sample repository for remote recipes.

What’s new:

Please see the CHANGELOG.

Quickstart

Install:

$ gem install sunzi

Go into your project directory (if it’s a Rails project, config would be a good place to start with), then:

$ sunzi create

It generates a sunzi folder along with subdirectories and templates. Inside sunzi, there are sunzi.yml and install.sh. Those two are the most important files that you mainly work on.

Go into the sunzi directory, then run sunzi deploy:

$ cd sunzi
$ sunzi deploy example.com

Now, what it actually does is:

1. Compile sunzi.yml to generate variables and retrieve remote recipes, then copy files into the compiled directory
2. SSH to example.com and login as root
3. Transfer the content of the compiled directory to the remote server and extract in $HOME/sunzi
4. Run install.sh on the remote server

As you can see, all you need to do is edit install.sh and add some shell commands. That’s it.

A Sunzi project without any recipes or roles is totally fine, so that you can start small, go big as you get along.

Commands

$ sunzi                                           # Show command help
$ sunzi create                                    # Create a new Sunzi project
$ sunzi deploy [user@host:port] [role] [--sudo]   # Deploy Sunzi project

Directory structure

Here’s the directory structure that sunzi create automatically generates:

sunzi/
  install.sh      # main script
  sunzi.yml       # add custom variables and remote recipes here

  recipes/        # put commonly used scripts here, referred from install.sh
    sunzi.sh
  roles/          # when role is specified, scripts here will be concatenated
    db.sh         # to install.sh in the compile phase
    web.sh
  files/          # put any files to be transferred

  compiled/       # everything under this folder will be transferred to the
                  # remote server (do not edit directly)

How do you pass dynamic values?

In the compile phase, variables defined in sunzi.yml are accessible from any files in the form of <%= @vars.ruby_version %>

For instance, given the following install.sh:

echo "Goodbye <%= @vars.goodbye %>, Hello <%= @vars.hello %>!"

With sunzi.yml:

vars:
  goodbye: Chef
  hello: Sunzi

Now, you get the following result.

Goodbye Chef, Hello Sunzi!

Remote Recipes

Recipes can be retrieved remotely via HTTP. Put a URL in the recipes section of sunzi.yml, and Sunzi will automatically load the content and put it into the compiled/recipes folder in the compile phase.

For instance, if you have the following line in sunzi.yml,

recipes:
  rvm: https://raw.githubusercontent.com/kenn/sunzi-recipes/master/ruby/rvm.sh

rvm.sh will be available and you can refer to that recipe by source recipes/rvm.sh.

You may find sample recipes in this repository useful: https://github.com/kenn/sunzi-recipes

Role-based configuration

You probably have different configurations between web servers and database servers.

No problem - how Sunzi handles role-based configuration is refreshingly simple.

Shell scripts under the roles directory, such as web.sh or db.sh, are automatically recognized as a role. The role script will be appended to install.sh at deploy, so you should put common configurations in install.sh and role specific procedures in the role script.

For instance, when you set up a new web server, deploy with a role name:

sunzi deploy example.com web

It is equivalent to running install.sh, followed by web.sh.

Vagrant

If you’re using Sunzi with Vagrant, make sure that you have a root access via SSH.

An easy way is to edit Vagrantfile:

Vagrant.configure("2") do |config|
  config.vm.provision "shell",
    inline: "sudo echo 'root:vagrant' | /usr/sbin/chpasswd"
  end
end

and now run vagrant up, it will change the root password to vagrant.

Also keep in mind that you need to specify the port number 2222.

$ sunzi deploy localhost:2222

Demonstration Videos

You can watch video on how to deploy a Rails 4.1 app with Sunzi and Capistrano 3 at http://youtu.be/3mwupXqtkmg