Runtime Extensions

Important

The RuntimeSDK feature flag must be set to true in order to use this feature; please check documentation of different set of hooks to check if additional feature flags are required. See Feature Gates for more details.

The Runtime SDK feature provides an extensibility mechanism that allows systems, products, and services built on top of Cluster API to hook into a workload cluster’s lifecycle.

Caution

Please note Runtime SDK is an advanced feature. If implemented incorrectly, a failing Runtime Extension can severely impact the Cluster API runtime.

Feature gate name: RuntimeSDK

Variable name to enable/disable the feature gate: EXP_RUNTIME_SDK

Additional documentation:

• Background information:
  • Runtime SDK CAEP
  • Topology Mutation Hook CAEP
  • Runtime Hooks for Add-on Management CAEP
• For Runtime Extension developers:
  • Implementing Runtime Extensions
  • Implementing In-Place Update Hooks Extensions
  • Implementing Lifecycle Hook Extensions
  • Implementing Topology Mutation Hook Extensions
  • Implementing Upgrade Plan Runtime Extensions
• For Cluster operators:
  • Deploying Runtime Extensions