ParentRefs references the resources (usually Gateways) that a Route wants
to be attached to. Note that the referenced parent resource needs to
allow this for the attachment to be complete. For Gateways, that means
the Gateway needs to allow attachment from Routes of this kind and
namespace. For Services, that means the Service must either be in the same
namespace for a "producer" route, or the mesh implementation must support
and allow "consumer" routes for the referenced Service. ReferenceGrant is
not applicable for governing ParentRefs to Services - it is not possible to
create a "producer" route for a Service in a different namespace from the
Route.
There are two kinds of parent resources with "Core" support:
* Gateway (Gateway conformance profile)
* Service (Mesh conformance profile, ClusterIP Services only)
This API may be extended in the future to support additional kinds of parent
resources.
ParentRefs must be distinct. This means either that:
* They select different objects. If this is the case, then parentRef
entries are distinct. In terms of fields, this means that the
multi-part key defined by group, kind, namespace, and name must
be unique across all parentRef entries in the Route.
* They do not select different objects, but for each optional field used,
each ParentRef that selects the same object must set the same set of
optional fields to different values. If one ParentRef sets a
combination of optional fields, all must set the same combination.
Some examples:
* If one ParentRef sets sectionName, all ParentRefs referencing the
same object must also set sectionName.
* If one ParentRef sets port, all ParentRefs referencing the same
object must also set port.
* If one ParentRef sets sectionName and port, all ParentRefs
referencing the same object must also set sectionName and port.
It is possible to separately reference multiple distinct objects that may
be collapsed by an implementation. For example, some implementations may
choose to merge compatible Gateway Listeners together. If that is the
case, the list of routes attached to those resources should also be
merged.
Note that for ParentRefs that cross namespace boundaries, there are specific
rules. Cross-namespace references are only valid if they are explicitly
allowed by something in the namespace they are referring to. For example,
Gateway has the AllowedRoutes field, and ReferenceGrant provides a
generic way to enable other kinds of cross-namespace reference. |