A feature flag is a Boolean-controlled configuration mechanism that enables or disables a feature, resource, dependency, or attribute.
A feature flag is a Boolean configuration mechanism that enables or disables infrastructure resources, dependencies, or attributes. It stages changes while preserving the existing infrastructure state. section 10.1.2
Apply a feature flag through a short lifecycle:
Define the flag in one visible location, such as a dedicated configuration file or configuration manager. section 10.1.2section 10.3
Default it to False so the original resources and dependencies remain unchanged. section 10.1.2
Reference the flag in infrastructure configuration to select the existing or replacement resources. section 10.1.2
Set it to True when the staged change is ready, then remove the flag after the change completes. section 10.1.2section 10.3
Staging servers behind a load balancer
With ENABLE_SERVER_MODULE set to False, the load balancer keeps the original servers. Setting it to True attaches three module-created servers and detaches the old servers; the completed configuration removes the conditional flag. section 10.1.2
How Infrastructure as Code, Patterns and Practices: With examples in Python and Terraform covers it
How deep it goes
Demonstrates definition, defaulting, conditional references, activation, and removal, but does not detail configuration-manager implementation.
Examples
Uses Python, JSON, Terraform, and CloudFormation examples to switch server modules and load-balancer membership.
What it assumes
Assumes familiarity with infrastructure as code, resources, dependencies, and conditional configuration.
What you can do after
Apply it via infrastructure as code to stage changes and limit their immediate impact on existing resources.
How it connects
Connects feature flags with infrastructure as code, refactoring, rolling updates, trunk-based development, and blue-green deployment.
Platform Engineering on KubernetesA feature flag is a runtime-controlled configuration mechanism that enables or disables application functionality without changing or restarting the application.
Django in ActionA feature flag is a conditional control that enables or disables application functionality according to configuration or runtime criteria.
Learn Rust in a Month of LunchesA feature flag is a configuration option that conditionally enables code, dependencies, or capabilities during compilation.
rollbackused by · Rollback is the reversal or discarding of changes to restore data, software, or system state to an earlier or otherwise valid state.
strangler patternused by · The strangler pattern is an incremental modernization approach that replaces a legacy system by gradually transferring its functionality to a new system until the legacy system can be retired.
OpenFeatureused by · OpenFeature is an open standard and API for consuming and evaluating feature flags independently of the underlying provider.
model architecturepart of · The structural organization of a computational system’s components, relationships, and operations that determines how it processes information or behaves.
text-to-speech conversionconfigures · Text-to-speech conversion is the computational synthesis of spoken audio from written text.
This explainer was generated by Manning's knowledge graph from the text of Infrastructure as Code, Patterns and Practices: With examples in Python and Terraform. The section links point to the parts of the book it draws on.
