Chef is the platform for automating your infrastructure on Amazon Web Services. Chef is a configuration management tool written in Ruby and Erlang. It uses a pure-Ruby, domain-specific language (DSL) for writing system configuration "recipes". Chef is used to streamline the task of configuring and maintaining a company's servers, and can integrate with cloud-based platforms such as Internap, Amazon EC2, Google Cloud Platform, OpenStack, SoftLayer, Microsoft Azure and Rackspace to automatically provision and configure new machines. Chef contains solutions for both small and large scale systems, with features and pricing for the respective ranges.
The user writes "recipes" that describe how Chef manages server applications and utilities (such as Apache HTTP Server, MySQL, or Hadoop) and how they are to be configured. These recipes (which can be grouped together as a "cookbook" for easier management) describe a series of resources that should be in a particular state: packages that should be installed, services that should be running, or files that should be written. These various resources can be configured to specific versions of software to run and can ensure that software is installed in the correct order based on dependencies. Chef makes sure each resource is properly configured and corrects any resources that are not in the desired state.
Chef can run in client/server mode, or in a standalone configuration named "chef-solo". In client/server mode, the Chef client sends various attributes about the node to the Chef server. The server uses Solr to index these attributes and provides an API for clients to query this information. Chef recipes can query these attributes and use the resulting data to help configure the node.
Chef allows you to define, create, and manage your entire application stack on AWS. With a single recipe you can manage and orchestrate a multi-tier application that relies on a variety of AWS services such as Amazon Virtual Private Cloud (Amazon VPC), Amazon Elastic Compute Cloud (Amazon EC2), elastic load balancing (ELB), Amazon Simple Storage Service (Amazon S3), and Amazon Relational Database Service (Amazon RDS) relational database service (RDS). Because Chef recipes describe resources in the order of their execution, you can ensure that, for example, an RDS database is created and populated before enabling the Amazon EC2 instances that connect to it.