index.md

Experimental Feature: Runtime SDK (alpha)

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.

All currently implemented hooks require to also enable the ClusterClass feature.

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 Lifecycle Hook Extensions
  • Implementing Topology Mutation Hook Extensions
• For Cluster operators:
  • Deploying Runtime Extensions