Selector is a CEL expression which must evaluate to true if a resource instance is suitable. The language is as defined in https://kubernetes.io/docs/reference/using-api/cel/ In addition, for each type NamedResourcesin AttributeValue there is a map that resolves to the corresponding value of the instance under evaluation. For example: attributes.quantity["a"].isGreaterThan(quantity("0")) && attributes.stringslice["b"].isSorted()