Chef Architecture: Overview of Chef Infra

Chef is an open-source configuration management tool developed by Opscode to solve the problem of manual and repetitive infrastructure management tasks. Chef is programmed in Ruby DSL and uses a declarative approach to be more user serving. It mostly uses a client-server model but can also run standalone. (Chef Solo) 

Users write system configuration files that are called ‘Recipes’, which are then organized into ‘Cookbooks’. These configuration files define the desired state of the infrastructure, like which packages should be installed, which services should be running, or which files should be written. This allows Chef to compare the current state of resources to their optimal state, and take the necessary actions to correct them.

Chef is compatible with many different cloud platforms. This includes AWS, GCP, OpenStack, SoftLayer, and others. Getting a Chef infrastructure up requires a series of steps detailed below: 

Components Of Chef Infra  

Chef is divided down into three basic components: the workstation, the server, and the nodes also referred to as the 3 tier architecture. Let us discuss each of them briefly before moving on to the details. 

The Chef Workstation runs on your everyday computer, whether it’s on Windows, Linux or macOS, and is used to administer your infrastructure and configure it using a file known as a “recipe”. A recipe is a configuration file written in Ruby to configure and manage the infrastructure.

The second component, the Chef Server, is the intermediary between the workstation and the node architecture. After the configuration files have been programmed and tested on the workstation, they are uploaded on the server which acts as a hub for configuration data. The server, which can be hosted locally or remotely, provides the necessary tools to drive the node architectural settings. 

Nodes, or the systems needing the configuration, are the final part. Chef allows for multiple collection of data on node states at once. After this data is gathered, it is forwarded to the server to be compared with the configuration files and for any necessary adjustments to be made. It is easy to learn the complete Chef architecture through an online Chef course.

Now let us discuss each of the components in detail.

Workstations 

The PC that is running Chef Workstation is known as a workstation on Chef. Authoring cookbooks, interacting with nodes, and managing the Chef Infra Server are all made easier with the Chef Workstation.

Chef Workstation is used to perform the following tasks: 

• Cookbooks and recipes are being developed and tested. 
• Validating Chef's source code. 
• Keeping the Chef repository in sync with the source code revision control system. 
• Requirement-based node interaction, including, for example, performing a bootstrap procedure. 
• Set corporate policy, outline employee responsibilities, Chef roles and work conditions, and ensure sensitive information is safely stored in data bags. 

The wide variety of functions and the simplicity of installation are only two of the many advantages of Chef Workstation. Remote scanning and setup jobs, as well as ad hoc remote execution, are all made possible with the help of the Chef Workstation. 

Components of Chef Workstations 

1. chef-repo 

The Chef -repo folder on the client server is where cookbooks and other supplementary resources like roles, data bags, and conditions are kept. The Chef pushes updates to the server from the chef-repo using knife commands. 

The command to create a new Chef repository is 'Chef generate repo repo-name. 

2. Knife 

The knife, a command-line interface tool, is the primary technique by which a client machine communicates the data of its chef-repo directory to a Chef server. This communication takes place between the client computer and the Chef server. User-friendly controls let you organize your network's nodes, cookbooks, environments, roles, and data bags. 

3. Test Kitchen 

Kitchen facilitates preparing, testing, and refining recipes before their deployment to the user's production nodes. Kitchen is a command line program that enables users to execute integration tests across several platforms, simulating a wide range of nodes in a production environment. 

The essential command-line tools found in Chef Workstation are: 

Chef: To control what is stored in a chef-repo, the hub for developing, testing, and maintaining recipes, and the origin of policies uploaded to the Chef server, utilize the chef command prompt tool. 

Knife: A knife is the Chef server's command line interface for managing nodes and objects. 

chef-client: For setting up your cluster's infrastructure, use an agent called chef-client. 

Test Kitchen: Test Kitchen is an automated testing framework for the Chef programming language. 

InSpec: Chef's InSpec is a free and open-source automation platform for security and compliance. 

chef-run: As a tool for executing random jobs, "chef-run" is a boon to the modern IT professional. 

chef-run: The Chef Workstation App manages and keeps your chef equipment up-to-date. 

Every one of these tools and components can be learned and mastered through the best courses for DevOps offered.

Cookbooks  

In Chef Infra, a Cookbook is the basic unit of configuration and policy distribution. You can think of a cookbook as a collection of all the recipes, files, characteristics, and metadata you'll need to implement a specific scenario. In addition, it has Chef extensions for various uses, file distributions, templates, attribute values, and more. The components of Chef Cookbooks include: 

1. Recipes 

The second major component of Chef Cookbooks' framework is recipes. The inclusion of a Chef Recipe is a standard feature in Chef Introduction books. To the extent that a cookbook can be thought of as a basic unit of configuration, a recipe may be thought of as its smallest subunit. Resources, such as names, actions, and attribute-value pairs, are defined in detail in the Chef Recipe. 

2. Attributes 

A characteristic may be specified in a recipe, a function description, or a natural setting. Furthermore, it can be used to alter the settings of a package or program's Chef server application. The following server snippet demonstrates how to change Apache's default port to 80 using an attribute. 

3. Files 

It is possible to share files in a cookbook by node, platform, or version. 

4. Libraries 

Every introduction to the Chef would not be complete without mentioning the library. Using libraries, any Ruby code may be integrated into a recipe. Libraries' most common usage is in the creation of reusable aids for use in several recipes and user-created resources. 

5. Metadata 

A small bit of metadata is required for every cookbook. At the root of every cookbook's directory tree sits a file called "metadata.rb." The "metadata.rb" file contains crucial information for the proper installation of cookbooks on every node. 

6. Resources 

Chef Cookbooks also include a section on resources, which can be found in the official Chef DevOps Documentation. The policy declarations of a configuration are the resources. You can achieve the desired configuration state for an entity by referring to a resource, which describes that state and declares the actions to take to get there. A resource type, such as "service," "package," or "template," is also specified in the configuration policy. 

7. Templates and Tests 

Chef Cookbooks also feature test plans and sample code for projects. The Embedded Ruby (ERB) template in the cookbooks allows for the production of static text files in a dynamic fashion. It is important to put cookbooks through rigorous testing to ensure they are of the highest possible standard. Since this is the case, Chef Cookbooks must incorporate not only unit and integration testing but also syntax testing. 

Nodes 

A Node is a device that is under management by Chef Infra. Nodes can be of any type, i.e: physical, virtual, cloud, network device, etc. Chef Infra Client is pre-installed on every node, and it is compatible with a wide variety of operating systems.

Interested in learning everything about Chef infra? You can join the KnowledgeHut’s online Chef course to be an expert.

Node Types 

1. Server Node 

A server or virtual machine is an example of a physical node; however, any active device connected to a network that can transmit, receive, and forward data is technically a physical node. Basically, a physical node is any networked computer that is up and capable of running the Chef-client and exchanging data with the Chef server. 

2. Cloud Node

An Amazon Web Services (AWS) or OpenStack server, Rackspace server, Google Compute Engine instance, architecture of web server or Microsoft Azure virtual machine are all examples of cloud-based nodes. The knife has add-ons that allow it to work with many third-party cloud providers. These plugins allow knives to make versions on cloud-based services. Once instances have been made, the client server architecture can be utilized to deploy, configure, and manage them. 

3. Network Node

Any router or switch being managed by a chef-client falls under the umbrella term "network node." This includes equipment from Juniper Networks, Arista, Cisco, and F5. Common networking settings for these gadgets, like Ethernet link characteristics and VLAN addressing, can be set automatically with the help of client server computing. 

Chef on Node 

The term "chef on node" refers to an execution in which a chef-client is hosted by and operates within a node as a job and is housed within a VM or container. 

Initially, the chef-client is executed as a node-based task. It's a utility for running a set of node-related tasks on the chef-server. The actions provided by the chef-client are merely the tip of the iceberg. 

Node administration is handled by Chef on a node. This is a crucial feature of the chef-client. The Chef client is a node-based task. 

The Chef server can be installed on a standalone computer or a cluster. It is the job of this server to process client requests, oversee the nodes, and grant access to the client and server resources. Chef automation also offers an application programming interface (API) for integration with other applications. 

The Chef Infra Server 

The Chef Infra server is a hub for configuration data, and is used to store cookbooks, the node policies, and the metadata that describes each registered node. The Chef Infra Client is used to communicate to the Chef Infra Server by the nodes to request configuration details, such as recipes, templates, and file distributions.

Predefined recipes and cookbook actions are used by the Chef Server Plugins to control the node. When you install the chef-server, you'll have access to a library of plugins known collectively as the Chef Server Plugins. Through the use of these plugins, all nodes can be controlled and monitored according to a set of predetermined recipes, cookbooks, and actions. 

Policy  

Using this function, the chef-server can control who can access which parts of the infrastructure and what changes can be made. The chef-client is used to configure and deploy policies to nodes, and it is also used to make changes to those rules. A set of add-ons that can be used with the chef-server. 

Conclusion 

Chef works with several cloud providers, including Amazon Web Services (AWS), Google Cloud Platform (GCP), OpenStack (OpenStack), SoftLayer (SoftLayer), and others. It's a program that helps automate the process of turning physical structures into computer programs. Instead of relying on manual labor, the emphasis is on creating software. Because of this, Chef can easily manage and set up several systems at once. Using Chef, we can continually deploy and test the code.