You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
87 lines
4.2 KiB
87 lines
4.2 KiB
7 years ago
|
.. _config_http_conn_man_rds:
|
||
|
|
|
||
|
|
Route discovery service
|
||
|
|
=======================
|
||
|
|
|
||
|
|
The route discovery service (RDS) API is an optional API that Envoy will call to dynamically fetch
|
||
|
|
:ref:`route configurations <config_http_conn_man_route_table>`. A route configuration includes both
|
||
|
|
HTTP header modifications, virtual hosts, and the individual route entries contained within each
|
||
|
|
virtual host. Each :ref:`HTTP connection manager filter <config_http_conn_man>` can independently
|
||
|
|
fetch its own route configuration via the API.
|
||
|
|
|
||
|
|
.. code-block:: json
|
||
|
|
|
||
|
|
{
|
||
|
|
"cluster": "...",
|
||
|
|
"route_config_name": "...",
|
||
|
|
"refresh_delay_ms": "..."
|
||
|
|
}
|
||
|
|
|
||
|
|
cluster
|
||
|
|
*(required, string)* The name of an upstream :ref:`cluster <config_cluster_manager_cluster>` that
|
||
|
|
hosts the route discovery service. The cluster must run a REST service that implements the
|
||
|
|
:ref:`RDS HTTP API <config_http_conn_man_rds_api>`. NOTE: This is the *name* of a cluster defined
|
||
|
|
in the :ref:`cluster manager <config_cluster_manager>` configuration, not the full definition of
|
||
|
|
a cluster as in the case of SDS and CDS.
|
||
|
|
|
||
|
|
route_config_name
|
||
|
|
*(required, string)* The name of the route configuration. This name will be passed to the
|
||
|
|
:ref:`RDS HTTP API <config_http_conn_man_rds_api>`. This allows an Envoy configuration with
|
||
|
|
multiple HTTP listeners (and associated HTTP connection manager filters) to use different route
|
||
|
|
configurations. By default, the maximum length of the name is limited to 60 characters. This
|
||
|
|
limit can be increased by setting the :option:`--max-obj-name-len` command line argument to the
|
||
|
|
desired value.
|
||
|
|
|
||
|
|
refresh_delay_ms
|
||
|
|
*(optional, integer)* The delay, in milliseconds, between fetches to the RDS API. Envoy will add
|
||
|
|
an additional random jitter to the delay that is between zero and *refresh_delay_ms*
|
||
|
|
milliseconds. Thus the longest possible refresh delay is 2 \* *refresh_delay_ms*. Default
|
||
|
|
value is 30000ms (30 seconds).
|
||
|
|
|
||
|
|
.. _config_http_conn_man_rds_api:
|
||
|
|
|
||
|
|
REST API
|
||
|
|
--------
|
||
|
|
|
||
|
|
.. http:get:: /v1/routes/(string: route_config_name)/(string: service_cluster)/(string: service_node)
|
||
|
|
|
||
|
|
Asks the route discovery service to return the route configuration for a particular
|
||
|
|
`route_config_name`, `service_cluster`, and `service_node`. `route_config_name` corresponds to the
|
||
|
|
RDS configuration parameter above. `service_cluster` corresponds to the :option:`--service-cluster`
|
||
|
|
CLI option. `service_node` corresponds to the :option:`--service-node` CLI option. Responses are a
|
||
|
|
single JSON object that contains a route configuration as defined in the :ref:`route configuration
|
||
|
|
documentation <config_http_conn_man_route_table>`.
|
||
|
|
|
||
|
|
A new route configuration will be gracefully swapped in such that existing requests are not
|
||
|
|
affected. This means that when a request starts, it sees a consistent snapshot of the route
|
||
|
|
configuration that does not change for the duration of the request. Thus, if an update changes a
|
||
|
|
timeout for example, only new requests will use the updated timeout value.
|
||
|
|
|
||
|
|
As a performance optimization, Envoy hashes the route configuration it receives from the RDS API and
|
||
|
|
will only perform a full reload if the hash value changes.
|
||
|
|
|
||
|
|
.. attention::
|
||
|
|
|
||
|
|
Route configurations that are loaded via RDS are *not* checked to see if referenced clusters are
|
||
|
|
known to the :ref:`cluster manager <config_cluster_manager>`. The RDS API has been designed to
|
||
|
|
work alongside the :ref:`CDS API <config_cluster_manager_cds>` such that Envoy assumes eventually
|
||
|
|
consistent updates. If a route references an unknown cluster a 404 response will be returned by
|
||
|
|
the router filter.
|
||
|
|
|
||
|
|
Statistics
|
||
|
|
----------
|
||
|
|
|
||
|
|
RDS has a statistics tree rooted at *http.<stat_prefix>.rds.<route_config_name>.*.
|
||
|
|
Any ``:`` character in the ``route_config_name`` name gets replaced with ``_`` in the
|
||
|
|
stats tree. The stats tree contains the following statistics:
|
||
|
|
|
||
|
|
.. csv-table::
|
||
|
|
:header: Name, Type, Description
|
||
|
|
:widths: 1, 1, 2
|
||
|
|
|
||
|
|
config_reload, Counter, Total API fetches that resulted in a config reload due to a different config
|
||
|
|
update_attempt, Counter, Total API fetches attempted
|
||
|
|
update_success, Counter, Total API fetches completed successfully
|
||
|
|
update_failure, Counter, Total API fetches that failed (either network or schema errors)
|
||
|
|
version, Gauge, Hash of the contents from the last successful API fetch
|