Feature Gates

kro uses Kubernetes-style feature gates to manage alpha and experimental functionality. Feature gates let you enable or disable specific features at controller startup without code changes.

Configuring Feature Gates

Enable feature gates in your Helm values:

config:
  featureGates:
    CELOmitFunction: true

Or pass the flag directly to the controller binary:

--feature-gates=CELOmitFunction=true,InstanceConditionEvents=true

Available Feature Gates

Feature Gate	Default	Stage	Since	Description
CELOmitFunction	false	Alpha	v0.9.0	Enables the omit() CEL function for conditional field omission in resource templates.
InstanceConditionEvents	false	Alpha	v0.9.0	Emits Kubernetes Events on instance status condition transitions.

CELOmitFunction

When enabled, CEL expressions in resource templates can return omit() to remove the containing field from the rendered object instead of writing a value. This is useful for CRDs that distinguish between field absence and an explicit null or empty value.

spec:
  resources:
    - id: deployment
      template:
        spec:
          replicas: ${schema.spec.replicas > 0 ? schema.spec.replicas : omit()}

Since kro uses Server-Side Apply, an omitted field is no longer managed by kro. Any external changes to that field will not be detected or reverted.

When this gate is disabled, any RGD that uses omit() is rejected at build time.

InstanceConditionEvents

When enabled, kro emits Kubernetes Events on the instance object whenever a status condition transitions (e.g. ResourcesReady from False to True). These events are visible via kubectl describe and can be used for alerting or debugging.