Opscode Chef is a configuration management tool used to streamline the task of configuring and maintaining a company's servers. It can integrate with cloud-based platforms such as Rackspace, Amazon EC2, Google Cloud Platform, OpenStack and Microsoft Azure to automatically provision and configure new machines.
The user writes "recipes" that describe how Chef manages server applications (such as Apache HTTP Server, MySQL, or Hadoop) and how they are to be configured. These recipes 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. 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. Traditionally, Chef is used to manage Linux but later versions support Microsoft Windows as well.