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This article mainly explains "what is Chef". The content of the explanation is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "what is Chef".

What is Chef?

Automation for Web-Scale IT.Chef delivers fast, scalable, flexible IT automation.

To put it simply, Chef is an IT automation tool. It abstracts the server environment (software, dependent library, network, etc.), manages it with a unique configuration syntax (Ruby language, Chef is developed by Ruby), and can initialize the server environment automatically.

Why is there Chef?

Imagine that when we need to build a site, we need to install a server, a server is fine, and it takes a while to install it. With the development of the website, we need to add a few more servers, it doesn't matter, it takes a little more time, but to do a cluster, we need to make sure that the environment of several servers is exactly the same, so many people use shell to write automatic installation scripts. But anyone who has written shell scripts knows how painful it is. With the development of the site, you may have to maintain hundreds of servers, and at this time, if you initialize the server environment with shell scripts and manual installation, the workload is simply unthinkable.

Before the emergence of Chef, there were already CFEngine, Puppet and other automated operation and maintenance tools. Since 2008, the Internet era has gradually entered the cloud era. The problem faced by operation and maintenance engineers is that it has grown from several or hundreds of servers to thousands, tens of thousands, or hundreds of thousands of servers. Therefore, it is very important to use a predictable and testable infrastructure, while the solutions provided by CFengine and Puppet lack such predictability and cannot be fully tested.

On the other hand, Chef calls the system management script written by the user "recipe", which allows the user to define server roles (such as web server and database server). The user can add the "recipe" to the role on demand. Chef executes the tasks defined in the menu in the order specified by the user. By default, if there is a problem that the task cannot be completed, Chef reports an error and exits. This makes it easier for engineers to know that there are errors in the script, modify it, test it, save production time, and improve efficiency (however, you can also configure Chef to run as a daemon to achieve the effect of convergence).

In addition, Chef uses Ruby-based DSL (Domain Specific Language) as the language in the "recipe" script, which is easy to understand for engineers who are more inclined to operation and maintenance, while for engineers who are more inclined to software development, they can use Ruby to extend the functionality of "recipe". At the same time, Chef can be included in software projects as a library, which really encourages and enables developers to consider deployment, scale, maintenance and planning capacity (capacity planning) in the design and development phase, and incorporate system configuration-level code into the code of internal network services.

With Chef's "recipes", engineers can record and save the entire infrastructure in easy-to-understand code. If the data center or indirect cloud service provider data center is destroyed by a tornado in an instant, Chef can quickly use these "recipes" and roles to allow you to build a whole new infrastructure to minimize service downtime in a production environment.

Also, the infrastructure configured with Chef is 100% predictable and testable.

For example, Chef is like a toy factory, it can make some raw materials into beautiful toys, it has some templates, you put the raw materials in, choose a template (such as Shrek), it will create the toy server configuration is the same, an unconfigured server, you assign it a template (role or recipe) Chef will configure it as the online server you want.

This is only one aspect of Chef, because you can install the system and execute a script to achieve the same goal. Chef has another aspect that scripts cannot achieve, that is, Chef has the ability to remotely control the configured server, and it can further configure or modify the system at any time, just like the previous toy factory can change the color of its toys at any time. Size (which seems unlikely in reality) you can also achieve your goal manually, but when there are more servers, the manual method may not be so fun. Chef provides a more convenient and unified approach.

Thank you for your reading, the above is the content of "what is Chef", after the study of this article, I believe you have a deeper understanding of what Chef is, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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