<p>An array of <code>EnvironmentVariable</code> objects that specify environment variables to be associated with the app. After you deploy the app, these variables are defined on the associated app server instances.For more information, see <a href="https://docs.aws.amazon.com/opsworks/latest/userguide/workingapps-creating.html#workingapps-creating-environment"> Environment Variables</a>.</p> <p>There is no specific limit on the number of environment variables. However, the size of the associated data structure - which includes the variables' names, values, and protected flag values - cannot exceed 20 KB. This limit should accommodate most if not all use cases. Exceeding it will cause an exception with the message, "Environment: is too large (maximum is 20 KB)."</p> <note> <p>If you have specified one or more environment variables, you cannot modify the stack's Chef version.</p> </note>