chef, vagrant and friends

CHEF, VAGRANT AND FRIENDS

AUTOMATING YOUR ENVIRONMENTS

@benmcrae

• Software engineer

• CompareTheMarket.com

• Travelling & listening to music

• Coffee / real ale drinker

MASTER CHEFS

SOFTWARE!CONFIGURATION MANAGEMENT

Chef can automate how you configure, deploy and scale your servers and applications.

GETTING STARTED

Installing Chef 11!

Chef Omnibus (Linux, OS X, Windows)

Chef DK (April 2014, v0.1.0) (Bundled software)

Gem (Ruby 1.9.3 recommended)

Chef CLI tools

ohai (node attributes)

chef-apply (execute a single recipe from the command line)

chef-solo (execute run lists and cookbooks on a node)

chef-client (retrieves & executes run lists & cookbooks on nodes)

knife (interact with chef server)

INFRASTRUCTURE AS CODE

ResourcesResources represent a piece of the system and its desired state. Some resources available:!

• Directories

• Users

• Groups

• Services

• Packages

Resource Syntax

A resource is a Ruby block with four components:

• A type

• A name

• One (or more) attributes (with values)

• One (or more) actions

RecipeRecipes are what you write to install and configure things on your machine.!

• Authored using a Ruby DSL

• Made from multiple resources

• Can include other recipes

• Single responsibility in purpose

• Belongs to a Cookbook

Recipe DSL

A Ruby DSL, with specific methods to write chef recipes and resource blocks.

Common Ruby syntax can be used with the Recipe DSL methods. if / case statements…

FIRST RECIPE

Ingredients

• Using chef-apply and a single recipe

• Create a new developer user on the system

• Install Git using the OS package manager

• Create a .gitconfig file for the developer user

stage-1https://github.com/benmcrae/ddd-chef-examples/tree/master/stage-1

https://github.com/benmcrae/ddd-chef-examples/tree/master/stage-1

Chef Run

• Recipe loaded

• Resources are arranged in an ordered queue

• Each resource is mapped to a Provider!

• The node Converges by executing each provider

Providers

Providers define steps that are needed to bring a piece of the system from its current

state into the desired state.

Idempotent

A recipe can run multiple times on the same system and the results will always be

identical.

RETROSPECTIVE

Outcomes

• Poor single responsibility

• Use better suited resources e.g. template / file

• Fixed values could be swapped for attributes

Next Steps

1. Create cookbook from existing recipe

2. Refactor outcomes from retrospective

FIRST COOKBOOK

Cookbook

A cookbook defines a scenario, such as everything needed to install and configure Apache and the resources that support it.

Cookbook Folders• attributes - attribute files, loaded in alphabetical order!

• files - stored files for file and directory resources!

• libraries - arbitrary ruby libraries, used in recipes!

• providers - custom providers (LWRP)!

• recipes - recipe files!

• resources - custom resources (LWRP)!

• templates - erb files for the template resource

Cookbook Generators

• knife cookbook create ‘cookbook name’

• berks cookbook ‘cookbook name’

Metadata File

• The metadata.rb sits in the cookbook root directory

• Defines cookbook name, version, and description

• Can declare dependencies on other cookbooks

• List supported operating systems

REFACTOR

Template Resource

• Uses ERB (Embedded Ruby) files

• Supports variables and hashes in templates

• Multi nested folders designed to support distributing files across platforms

• Best practice: set variables using attributes

Node Object

• Attributes - An attribute is a specific piece of data about the node!

• Run list - A run-list is an ordered list of recipes and/or roles that are run in an exact order

Attributes

!

• Attributes can be defined by the node, recipes, cookbooks, roles and environments!

• Node information. i.e. IP / MAC addresses, OS info

• Recipe information. i.e. directory paths, users, application data

Overriding Attributes

Ohai

Ohai is a CLI tool that is used to detect attributes on a node!

• Platform details

• Network usage

• Memory usage

• Processor usage

Run List

• A run-list defines all of the configuration settings that are necessary for a node to converge

• An ordered list of roles and/or recipes that are run in an exact order

chef-solo

• chef-solo allows using cookbooks on nodes without using Chef server

• Cookbooks & dependencies must be on the node

• Limited in functionality compared to chef-server

• Requires configuration; run-list and attributes

Chef Run• Builds node object!

• Expands run-list

• Compiles Resources in an ordered queue

• Each resource is mapped to a Provider!

• The node Converges by executing each provider

RETROSPECTIVE

Outcomes

• A single cookbook to manage our developer user

• A cookbook that can be used with both chef-solo and chef-client (Chef Server)

Next Steps

• Introduce community cookbooks and Berkshelf

• Install Ruby 2.1.2, using Berkshelf

COMMUNITY COOKBOOKS

Community Cookbooks• An online Open Source cookbook repository,

maintained and used by the chef community.

• Trusted cookbooks can be downloaded from - http://community.opscode.com

• Cookbook dependencies are not automatically downloaded. This must be done by looking through the cookbook metadata file, and manually downloading listed cookbooks.

http://community.opscode.com

Berkshelf

• The cookbook dependency manager

• gem install berkshelf

• Used to maintain cookbooks on your Chef Server

• Written by Jamie Windsor, and Seth Vargo

Berksfile• Lives in the root directory of the Cookbook

• Lists each cookbook name, and version (optional) which your cookbook depends on

• Ability to read cookbook dependencies from metadata.rb file

• Traverses over other cookbook dependencies

RETROSPECTIVE

Outcomes

• Implemented a community cookbook with the aid of Berkshelf.

• Applied our knowledge of attributes to other cookbooks.

Next Steps

• Provision the node automatically with chef-solo and Vagrant.

• Create a new recipe to git clone our ruby app into the developer home directory.

• Create and configure lightweight, reproducible, and portable development environments.

• Vagrant stands on the shoulders of giants. Machines are provisioned on top of VirtualBox, VMware, AWS, or any other provider.

• Provision machines with, shell scripts, Chef, or Puppet.

Commands• vagrant init hashicorp/precise32

• vagrant up

• vagrant provision

• vagrant halt

• vagrant destroy

Vagrant Provision

• Move the run list and attributes into the Vagrantfile

• Vagrant will run chef-solo on VM start, or by running the provision command

Git Resource

• Manage source control resources that exist in a git repository

• Functionality for revision and branching control

• Offers both export and syncing abilities

RETROSPECTIVE

Outcomes

• Used Vagrant to run chef-solo and setup our node

• Established our cookbook development workflow

• Finished cookbook

VAGRANT CONT.

More Features

• Full support for both Linux and Windows guest’s

• Mount directories using either NFS, SMB or Rsync

• Multi machine environments

• Network support - port forwarding, private networks

Vagrant Cloud

• Share a link to your web server to a teammate across the country

• Community collection of fully baked box images

• Distribute versionable private environments to your team

Share / Connect

• Share SSH access to other vagrant users

• Share the whole machine as a local entity to other vagrant users

Vagrant Plugins

• vagrant plugin install <plugin_name>

• vagrant-sahara (operate in a sandbox environment)

• vagrant-proxy (define http and https proxies)

Chef Reading• Test-Driven Infrastructure with Chef, 2nd Edition

- Steven Nelson-Smith

• Chef Infrastructure Automation Cookbook - Matthias Marschall

• Learning Chef (Released Sep 2014) - Seth Vargo, Mischa Taylor

• https://learnchef.opscode.com/

https://learnchef.opscode.com/

Vagrant Reading

• Vagrant: Up and Running - Mitchell Hashimoto

• http://docs.vagrantup.com/

• http://www.vagrantup.com/blog.html

http://docs.vagrantup.com/

http://www.vagrantup.com/blog.html

THANK YOU