Thanks for confirming! I've just merged the PR, so this change should be
in 1.46.
On Thu, Mar 17, 2022 at 3:21 PM František Bořánek <fbora...@gmail.com>
wrote:
>
> Works like a charm. All current channels are included in a first message
> during reconnection.
>
> Thanks very much.
>
> Here is from debug log:
>
> I0317 23:08:14.625789077 49 xds_client.cc:1287] [xds_client
> 0x7f89b40352a0] xds server xds-control-plane:10000: ADS call status
> received (chand=0x7f89b4042270, ads_calld=0x7f89f00fb600,
> call=0x7f89d0022e70): status=1, details='Received RST_STREAM with error
> code 8', error='"OK"'
> I0317 23:08:14.625866170 49 xds_client.cc:685] [xds_client
> 0x7f89b40352a0] xds server xds-control-plane:10000: start new call from
> retryable call 0x7f89b4189aa0
> I0317 23:08:14.625891228 49 xds_client.cc:938] [xds_client
> 0x7f89b40352a0] xds server xds-control-plane:10000: starting ADS call
> (calld: 0x7f89b8095930, call: 0x7f89b81801f0)
> D0317 23:08:14.626050477 49 xds_api.cc:257] [xds_client
> 0x7f89b40352a0] constructed ADS request: version_info:
> "8cbd8378-4243-4cc7-9a2f-1f075055a469"
> node: {
> cluster: "default-cluster"
> user_agent_name: "gRPC C-core linux"
> user_agent_version: "C-core 22.0.0"
> client_features: "envoy.lb.does_not_support_overprovisioning"
> 5: "gRPC C-core linux 22.0.0"
> }
> resource_names: "server-1"
> resource_names: "server-2"
> resource_names: "server-3"
> resource_names: "server-4"
> resource_names: "server-5"
> resource_names: "server-6"
> resource_names: "server-7"
> type_url: "type.googleapis.com/envoy.api.v2.Listener"
>
> I0317 23:08:14.626073893 49 xds_client.cc:1055] [xds_client
> 0x7f89b40352a0] xds server xds-control-plane:10000: sending ADS request:
> type=envoy.config.listener.v3.Listener
> version=8cbd8378-4243-4cc7-9a2f-1f075055a469 nonce= error="OK"
>
>
>
>
> 17. 3. 2022 v 21:56, Mark D. Roth <r...@google.com>:
>
> Thanks for reporting this! I think I see the problem, and it should be
> fixed by https://github.com/grpc/grpc/pull/29144.
>
> I don't see a trivial way to write a test for it, since the current
> behavior is not broken, just slightly sub-optimal. But feel free to try
> out the patch and let me know if it fixes the problem.
>
> On Thu, Mar 17, 2022 at 1:09 PM František Bořánek <fbora...@gmail.com>
> wrote:
>
>> It's not exactly the same version. This one is gRPC 1.43.2, but behaviour
>> do not vary form 1.44.0.
>> I attached also initial start up, in case you want to compare.
>> Reconnection of xds contains file goaway.from.xds.cpp.grpc.log.
>> The lifetime of channels are until shutdown of the application.
>>
>>
>>
>> 17. 3. 2022 v 16:52, Mark D. Roth <r...@google.com>:
>>
>> That's very interesting. Can you run with the following environment
>> variables and send me the log?
>>
>> GRPC_VERBOSITY=DEBUG GRPC_TRACE=xds_client,xds_resolver
>>
>> On Wed, Mar 16, 2022 at 10:53 PM František Bořánek <fbora...@gmail.com>
>> wrote:
>>
>>> C++, the latest 1.44.0 release.
>>>
>>> 16. 3. 2022 v 21:32, Mark D. Roth <r...@google.com>:
>>>
>>>
>>> It is valid behavior, but I agree that it's a little sub-optimal for the
>>> client to send two messages when it reestablishes the stream. What
>>> language are you using gRPC in?
>>>
>>> On Wed, Mar 16, 2022 at 1:19 PM František Bořánek <fbora...@gmail.com>
>>> wrote:
>>>
>>>> It makes sense.
>>>>
>>>> However, in this case, the initial connection was already made and this
>>>> tcpdump samples recovering of ADS stream. And as you write:
>>>>
>>>> > Note that once your application receives all 7 resources from the xDS
>>>> server, if the ADS stream is broken and the client reestablishes it at that
>>>> point, it should immediately subscribe to all 7 resources in the initial
>>>> message on the new stream.
>>>>
>>>> It behaves as I described. First 1 resource and then 7 resources. Note
>>>> that the messages have version_info. Brand new channels don't have
>>>> version_info.
>>>>
>>>> But as you pointed, the channels can be created anytime, thus it's
>>>> valid bahaviur.
>>>>
>>>> Thanks for replying.
>>>>
>>>> F.
>>>>
>>>> 16. 3. 2022 v 19:49, Mark D. Roth <r...@google.com>:
>>>>
>>>> The gRPC client does not know a priori what set of resource names are
>>>> available on the xDS server, and even if it did, it would not request all
>>>> of them proactively, because it may not actually need all of them.
>>>> Instead, each time a gRPC channel is created with an "xds:" target URI,
>>>> that tells gRPC which LDS resource to request, and it requests the
>>>> resources as they are needed. Because the application can create new
>>>> channels at any time, the set of resources requested on the ADS stream can
>>>> change at any time.
>>>>
>>>> If your application immediately creates 7 channels when it starts up,
>>>> then the pattern you're seeing is expected. When the first channel
>>>> (presumably for "xds:server-1") starts connecting, it will immediately
>>>> subscribe to the corresponding LDS resource ("server-1"). While it's
>>>> waiting for that message to be sent, it notices that the other 6 channels
>>>> have started up, so it realizes that it has to subscribe to the other 6
>>>> resources. By the time the initial message is sent and it's able to send a
>>>> second message, it knows about all 7 subscriptions, so the second message
>>>> contains all 7 of them.
>>>>
>>>> Note that once your application receives all 7 resources from the xDS
>>>> server, if the ADS stream is broken and the client reestablishes it at that
>>>> point, it should immediately subscribe to all 7 resources in the initial
>>>> message on the new stream. That is because it already knows about all of
>>>> the subscriptions at the point at which it sends the initial message on the
>>>> new stream.
>>>>
>>>> This communication is fully legal and should work fine with any
>>>> xDS-compliant server. As described in this section of the xDS spec
>>>> <https://www.envoyproxy.io/docs/envoy/latest/api-docs/xds_protocol#ack-nack-and-resource-type-instance-version>,
>>>> the intent of the version field in the DiscoveryRequest is to provide the
>>>> server with a way to know when it sends a version that the client considers
>>>> invalid. But if the client sends a second DiscoveryRequest with the same
>>>> version and a different list of resource names, that indicates that it is
>>>> changing what resources it is subscribing to, and the server cannot ignore
>>>> that just because the version is the same as one it has previously seen.
>>>>
>>>> I hope this information is helpful.
>>>>
>>>> On Mon, Mar 14, 2022 at 5:41 AM František Bořánek <fbora...@gmail.com>
>>>> wrote:
>>>>
>>>>> Hi,
>>>>> I don't know if such behaviour is a bug.
>>>>>
>>>>> I have server communicates with 7 services configured via XDS and
>>>>> after the xds-client got GO AWAY packet from XDS server 6 channels cannot
>>>>> connect due to error and only one is ok. I did a tcpdump to see a chat
>>>>> between our implementation of XDS and C++gRPC and cannot deside if C++gRPC
>>>>> behave correct.
>>>>>
>>>>> It relates to
>>>>> https://github.com/grpc/proposal/blob/master/A27-xds-global-load-balancing.md#initial-request-on-the-ads-stream
>>>>> > The first request on the ADS stream will include a Node
>>>>> message that identifies the client. As mentioned above, most of the fields
>>>>> for the Node message will be read from the bootstrap file.
>>>>>
>>>>> I would expect that after reconnect the xds client sends to ADS stream
>>>>> 4 requests (LDS, CDS, EDS, RDS) however it sends 5 requests (LDS, LDS,
>>>>> CDS,
>>>>> EDS, RDS). On our side of xds server we are confused by these 2 LDS
>>>>> requests.
>>>>>
>>>>> 1.
>>>>> (PROTOBUF) envoy.api.v2.DiscoveryRequest
>>>>> {
>>>>> version_info: "ba0255a2-07b6-45ed-83b4-dad0cbf96b1f"
>>>>> node: {
>>>>> cluster: "default-cluster"
>>>>> user_agent_name: "gRPC C-core linux"
>>>>> user_agent_version: "C-core 22.0.0"
>>>>> client_features: "envoy.lb.does_not_support_overprovisioning"
>>>>> build_version: "gRPC C-core linux 22.0.0"
>>>>> }
>>>>> resource_names: "server-1"
>>>>> type_url: "type.googleapis.com/envoy.api.v2.Listener"
>>>>> }
>>>>>
>>>>> 2.
>>>>> (PROTOBUF) envoy.api.v2.DiscoveryRequest
>>>>> {
>>>>> version_info: "ba0255a2-07b6-45ed-83b4-dad0cbf96b1f"
>>>>> resource_names: "server-1"
>>>>> resource_names: "server-2"
>>>>> resource_names: "server-3"
>>>>> resource_names: "server-4"
>>>>> resource_names: "server-5"
>>>>> resource_names: "server-6"
>>>>> resource_names: "server-7"
>>>>> type_url: "type.googleapis.com/envoy.api.v2.Listener"
>>>>> }
>>>>>
>>>>> - Shouldn't it be only one LDS request?
>>>>> - Shouldn't it the initial request contains all configured resources?
>>>>>
>>>>> Root of our problem is that we responds only on first request since it
>>>>> have the same version. I know how to fix it on our end, but it is
>>>>> behaviour
>>>>> of gRPC xds-client correct?
>>>>>
>>>>>
>>>>> --
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>>>>> <https://groups.google.com/d/msgid/grpc-io/e2a5befd-5943-4b40-afc4-4864938b9b88n%40googlegroups.com?utm_medium=email&utm_source=footer>
>>>>> .
>>>>>
>>>>
>>>>
>>>> --
>>>> Mark D. Roth <r...@google.com>
>>>> Software Engineer
>>>> Google, Inc.
>>>>
>>>>
>>>>
>>>
>>> --
>>> Mark D. Roth <r...@google.com>
>>> Software Engineer
>>> Google, Inc.
>>>
>>>
>>
>> --
>> Mark D. Roth <r...@google.com>
>> Software Engineer
>> Google, Inc.
>>
>>
>>
>
> --
> Mark D. Roth <r...@google.com>
> Software Engineer
> Google, Inc.
>
>
>
--
Mark D. Roth <r...@google.com>
Software Engineer
Google, Inc.
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