A Beginner’s Guide to Chef on CentOS 8

What is Chef?

Chef is an open-source configuration management DevOps tool used for configuration and management of multiple systems in infrastructure. Using Chef, we can use so-called recipes and cookbooks to automate and speed up managing multiple systems in our environment. By using Chef, we can adjust every system in our environment to our desired state, which we defined using the code in recipes. In the process, code is continuously tested and deployed using Chef.

It is worth noting that Chef is one of the tools used for configuration management. In a way, Chef is programming control of nodes in our environment. Some people would argue it is more inclined towards developers, whereas its competitor, Puppet, is more inclined towards system administrators. Read more about the comparison of configuration management tools (Ansible, Chef, SaltStack, and Puppet).

Recipes and Cookbooks

At the heart of Chef, we have recipes. A recipe is code written in Ruby, which consists of various configurations that we want to deploy. We can combine those recipes, along with other components such as attributes, files, libraries, etc., into building cookbooks (our workstations), which we can then deploy onto nodes.

A couple of advantages of Chef are the large support community and excellent online documentation. This assists users in finding widely available recipes since Chef is open-source software.

Knife

Knife is a command-line tool that enables communication (relay the contents of chef-repo) between recipes, cookbooks, and the Chef server. More importantly, Knife also allows us to manage nodes, cookbooks, environments, roles, data bags, resources, and the chef-client installation on the nodes.

Chef Setup

The Chef setup consists of three main components that we want to manage:

• Chef workstation
• Chef Infra server
• Chef nodes 

Inside the Chef workstation, we can create recipes and cookbooks to configure and manage our infrastructure. We can then upload those recipes and cookbooks onto the Infra server by using Knife.

The Chef Infra server is a “bridge” between the workstation and nodes. On the Infra server, which can be hosted locally or remotely, we can store recipes and cookbooks and deploy them on the nodes.

Chef nodes are hosts on the infrastructure that we want to configure and manage. Chef client service, which runs on the nodes, enables communication between the Chef Infra server and the nodes we want to deploy and manage.

In today’s example, we will cover installing Chef on CentOS 8. Before you proceed with it, ensure that you meet a few basic prerequisites:

• Enough system resources (check official system requirements)
• Make sure that network and firewall settings are in order.
• Enable NTP (Network Time Protocol) on your systems

How to Install the Chef Infra Server on CentOS 8

As a first step, we can navigate to our /tmp/ directory using the command.

cd /tmp/

After that, we can download the latest RPM package.

 [root@chefserver tmp]# curl -O https://packages.chef.io/files/stable/chef-server/14.0.65/el/7/chef-server-core-14.0.65-1.el7.x86_64.rpm
  % Total % Received % Xferd  Average Speed   Time Time  Time  Current
                              Dload  Upload   Total   Spent Left  Speed
100  241M  100  241M 0  0   840k   0  0:04:54  0:04:54 --:--:--  767k 

Alternatively, you can download the package from the website and then upload it to the system that will run Infra Server.

After the download is complete, we can install the RPM package with the following command.

[root@chefserver tmp]# rpm -Uvh chef-server-core-14.0.65-1.el7.x86_64.rpm
warning: chef-server-core-14.0.65-1.el7.x86_64.rpm: Header V4 DSA/SHA1 Signature, key ID 83ef826a: NOKEY
Verifying...                       ################################# [100%]
Preparing...                       ################################# [100%]
Updating / installing...
   1:chef-server-core-14.0.65-1.el7   ################################# [100%]

Configure Chef

After the RPM installation is complete, we can make cookbooks available by running the reconfigure command.

[root@chefserver]# chef-server-ctl reconfigure
 
Documentation: https://docs.chef.io/server_overview/
Patents:    https://www.chef.io/patents
 
+---------------------------------------------+
         Chef License Acceptance
 
Before you can continue, 3 product licenses
must be accepted. View the license at
https://www.chef.io/end-user-license-agreement/
 
Licenses that need accepting:
  * Chef Infra Server
  * Chef Infra Client
  * Chef InSpec
 
Do you accept the 3 product licenses (yes/no)?
 
> yes
 
Running handlers:
Running handlers complete
Chef Infra Client finished, 410/878 resources updated in 03 minutes 22 seconds
Chef Server Reconfigured!

Output for the reconfigure command can be quite large, so we have pasted only the product license acceptance prompt and the final output. Please note that running the reconfigure command can take several minutes to complete (as in our example), as resources have to be updated.

Additionally, chef-server-ctl is used to configure the Infra server, services, users, organizations, etc.

After the reconfigure command is done, we can use the following command to check the list of available software.

[root@chefserver]# chef-server-ctl service-list
bookshelf*
elasticsearch*
nginx*
oc_bifrost*
oc_id*
opscode-erchef*
postgresql*
redis_lb*

Create Admin User

The next step in the process is creating a Chef administrator/user. To do so, we can use the following command.

chef-server-ctl user-create USER_NAME FIRST_NAME LAST_NAME EMAIL 'PASSWORD' --filename FILE_NAME

In our example, we would input the information below.

root@chefserver]# chef-server-ctl user-create tom Thomas Janson tjanson@liquidweb.com 'us3str0ngp4$$w0rd_!' --filename /home/tom/tjanson.pem

Manage Users

We can use the following sub-commands to manage our users.

user-create
user-delete
user-edit
user-list
user-show

After we've created the user, we can proceed with creating an organization with the following syntax.

sudo chef-server-ctl org-create short_name 'full_organization_name' --association_user user_name --filename ORGANIZATION-validator.pem

Information for our example is below.

[root@chefserver]# chef-server-ctl org-create liquidweb 'Liquid Web' --association_user tom --filename /home/tom/org-validator.pem

The syntax for sub-commands for managing your organization is similar to managing users.

Conclusion

In today’s article, we covered the theoretical basics of Chef and how to install the Chef on CentOS 8. We recommend going through Chef's official documentation and scrolling through our extensive Knowledge Base for more information and tutorials about Chef and many other related topics.

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