COOKIN’ UP SERVERS WITH CHEF

Chef is an automation platform that streamlines the tasks of configuring machines. It also helps maintain the state of those machines. I am going to talk about the anatomy of Chef, show a code example, show how code become a configuration on a machine

CHEF ECOSYSTEM

The Chef Ecosystem has three main components. The Chef DK, Chef Server and Clients. The ChefDK is installed on a programmer’s workstation. The Chef Server is an on premise server or a Chef Managed instance. Clients are the machines that you want Chef to configure.

CHEF DK

The Chef DK is used to create "Cookbooks" describing the desired configuration a machine should be in. A Cookbook contains “recipes”. Recipes are code files written in Chef DSL based on Ruby.

CHEF DK

It is also used to create unit and integration tests to ensure the recipe is functioning properly.

CHEF SERVER

The Chef Server is a hub for configuration data. Chef server stores: Cookbooks Rules on how recipes are applied to clients Meta data to describe each client configuration..

CHEF CLIENTS

Clients are computers - physical, virtual or cloud that are managed by Chef. Each computer has the Chef Client installed. Chef Client is what does the configuring It runs in the background periodically. For each run it asks the Chef Server for recipes to execute, executes them to bring the configuration of the machine to its desired state

COOKBOOKS

Let’s take a deeper dive into the ChefDK Chef DK is used to create cookbooks. Cookbooks contain recipes related to each other A cookbook has many parts, recipes, attributes, environments, data_bags, Tests, libraries and custom resources. I am only going show you the most essential parts, recipes and tests.

RECIPES

A recipe contains a set of resources that describe what the state the machine should be. A resource is the “thing” you configure on the machine. Here is an example of a recipe that installs KanbanSim. When the chef client runs this recipe, it will run the resources in order.

RESOURCES

The first resource will create a directory “C:\KanbanSim”. The second resource will create a directory “C:\Chef-temp”.

RESOURCES

The remote_file resource will download the file in the source attribute and save it as C:\Chef-temp\KanbanSim-and-ScrumSim-v2.0.zip.

RESOURCES

The last resource will extract the zip file specified in the source attribute to the location set in the path attribute.

TESTING COOKBOOKS

Testing Cookbooks – one of the perks of describing your machine configuration as code is you can easily test it. Chef offers a couple of ways to do this. ChefSpec and InSpec.

TEST KITCHEN

You run the Inspec these tests in a tool called Test-Kitchen Test-Kitchen is a tool we used to run our cookbooks and test on our developer workstations. Kitchen uses vagrant + VirtualBox to create a VM from a base image. Then runs cookbooks and Inspec integration tests on the VM. Kitchen is also used to run ChefSpec unit tests.

CHEFSPEC

ChefSpec ChefSpec is a unit-testing framework for Chef. These tests run on the Developer’s workstation. Here is an example: TODO

INSPEC

InSpec is a compliance-testing framework. However, it has also been adopted as an Integration Testing framework for Cookbooks. These tests will run on the client machine.

CHEF SERVER

Chef Server The Chef server is a hub for configuration data. With Chef Server you can:

Manage User Security Manage Roles, which is a group of recipes. Roles are assigned to Client “Node The picture here shows a role called Jenkins_dotnet with three recipes in the run list Manage Client “Nodes” View Reports about Chef client runs

CHEF SERVER

You can also view node run history. If there is a problem the log is displayed in a nice readable format. If I were to scroll down it would show me a stack trace pointing to where in the recipe the run fail The details will show me step by step what resources were executed The Run list will tell what roles and recipes I have in the run list

CHEF WORKFLOW EXAMPLE

Ok let’s get out of the weeds a second and talk about what the workflow would look like to get a server with KanbanSim First I push the KanbanSim cookbook to git Which kicks off a Jenkins Job That downloads the code and runs my unit and integration tests Once those pass then the Jenkins job will call a tool called knife and upload the cookbooks Then we can use knife to install chef client on a server and assign that server a run list Once Chef Client is installed then it will start to configure the server. Then the server will periodically perform a run and check in with the Chef server

CHEF WORKFLOW EXAMPLE

Then the Jenkins job will call a tool called knife and upload the cookbooks Then we can use knife to install chef client on a server and assign that server a run list Once Chef Client is installed then it will start to configure the server. Then the server will periodically perform a run and check in with the Chef server

AWESOME TELL ME MORE

• More info on Chef https://learn.chef.io/

• More info in Inspec see https://www.chef.io/inspec/

• Food Fight Show podcast http://foodfightshow.org/

• Slack Chef Community Channel http://community-slack.chef.io/

Chef has a bunch of tutorials online The main use case for Inspec is compliance testing, which I can see our FDA regulated customers interested in it (cough) Food fight show podcast will give you insights on features you didn’t know existed and what is planned for the future Slack community channel seems pretty active, about 1500 members