package envoy.extensions.load_balancing_policies.override_host.v3

Get desktop application:
View/edit binary Protocol Buffers messages

Configuration for the Override Host Load Balancing policy. This policy allows endpoint picking to be implemented in downstream HTTP filters. For example an ext_proc RPC to a service that implements k8s proposal for AI gateway inferences extensions https://github.com/kubernetes-sigs/gateway-api-inference-extension/tree/main/docs/proposals/004-endpoint-picker-protocol can provide hosts for serving a request using Override Host load balancing policy. This policy extracts selected override hosts from a list of ``OverrideHostSource`` (request headers, metadata, etc.). The override host source must specify at least one host in ``IP:Port`` format or multiple hosts in ``IP:Port,IP:Port,...`` format. For example ``10.0.0.5:8080`` or ``[2600:4040:5204::1574:24ae]:80``. The IPv6 address is enclosed in square brackets. For specific example, to support k8s gateway inference extensions, which uses the ``x-gateway-destination-endpoint`` header or metadata value under the "envoy.lb" key for selected hosts, the Override Host load balancing policy should be configured in the following way: .. code-block:: yaml override_host_sources: - header: "x-gateway-destination-endpoint" - metadata: key: "envoy.lb" path: - key: "x-gateway-destination-endpoint" If no valid host in the override host list, then the specified fallback load balancing policy is used. This allows load balancing to degrade to a a built in policy (i.e. Round Robin) in case external endpoint picker fails. See the :ref:`load balancing architecture overview<arch_overview_load_balancing_types>` for more information.

• repeated OverrideHost.OverrideHostSource override_host_sources = 1

  A list of sources to get host addresses from. The host sources are searched in the order specified. The request is forwarded to the first address and subsequent addresses are used for request retries or hedging. Note that if an overridden host address is not present in the current endpoint set, it is skipped and the next found address is used. If there are not enough overridden addresses to satisfy all retry attempts the fallback load balancing policy is used to pick a host.

• optional config.cluster.v3.LoadBalancingPolicy fallback_policy = 3

  The child LB policy to use in case neither header nor metadata with selected hosts is present.

Used in: OverrideHost

• string header = 1

  The header to get the override host addresses. Only one of the header or metadata field could be set.

• optional type.metadata.v3.MetadataKey metadata = 2

  The metadata key to get the override host addresses from the request dynamic metadata. If set this field then it will take precedence over the header field. Only one of the header or metadata field could be set.