Engine Yard Glossary


In Engine Yard, there are certain product-specific terms that are often used by customers and agents. To improve understanding below is a frequently updated list of the terms and acronyms that are commonly used in Engine Yard.


The following terminology is used in the Engine Yard UI:

Term Definition
Application Master The application master is the instance to which the elastic IP address for the cluster is attached. The application master is the only instance within the cluster that gets traffic directly from the web. It is the cluster entry point, and so it load balances with HAProxy. When an application is deployed, the application master does the git fetch for the code and pushes the code to the other application instances. Also, deploy-related logs are held on the application master.
Applications An application is the web application that you are deploying to the cloud. Specifically, this is a definition of the various details regarding your application, such as where the code repository is, and any gem or package requirements it has.
Availability Zone

An availability zone is a logical data center in a region available for use by any AWS customer. Each zone in a region has redundant and separate power, networking and connectivity and is backed by one or more physical data centers to reduce the likelihood of two zones failing simultaneously. While a single availability zone can span multiple data centers, no two zones share a data center.

See Availability Zones in the AWS documentation for more information.

CLI Command Line Interface. For information about using the Engine Yard CLI, see Engine Yard CLI User Guide.
ebuilds The Gentoo linux distribution uses ebuilds to specify instructions on how to “built” from source a specific library or binary. So if your application requires the “ImageMagick” library, you need to install the library. See Add unix packages to your application for more detailed instructions.  
Environments Environments are a way to separate and categorize your instances according to intended usage. For example, you might have a “staging” environment and a “production” environment.
EIP Elastic IP addresses are the public IP addresses assigned to a given environment.
Git Repository URI

This is the URL of your repository from which your application is deployed. For example, a git repository at GitHub might have a URL that looks similar to: git@github.com:engineyard/vertebra.gitor https://github.com/engineyard/vertebra.git, representing the SSH and HTTPS URI respectively for the same repository.

Instances These are the virtualized servers that your applications run on.
IP addresses IP Addresses are a means of identifying a specific entity on a TCP/IP network. Specifically, you use the IP address to connect to your instance via SSH and to point your domain DNS records to.
Root partitions In the file system, we refer to the root partition as the primary volume that the Linux filesystem resides on.
SSH Keys SSH Keys are a means of secure, passwordless authentication. The “public” key is installed on your instance. The “private” key is on your local computer, and grants you access to the instance when you SSH in.
Takeovers Takeover is the Engine Yard process for recovering from an application master failure. For more information about takeovers, see Application master takeover.
Volumes These are the virtual disks that are mounted at /data and /db on your instance and are used to store data that needs to be persistent.


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