Is here have any way to custom c-core , I want to build c-core for myself , and want to realize balancing and nameresolve in Python .
在2020年10月29日星期四 UTC+8 上午7:01:53<Mark D. Roth> 写道： > If I understand the scenario here correctly, each client has many > different server names, and those server names change over time. What > determines this list of server names for a given client to use, and how > does the client get the list of server names to use? Can you just publish > all of the addresses under a single server name via your name service > (whether it be DNS or zookeeper or whatever)? That would probably be the > easiest way to deal with this, because then you could just have a single > channel with a single name, and you'd automatically get a separate > subchannel for every address, which you could use with the round_robin LB > policy. > > If for some reason you can't do that, then architecturally, you would need > to create a custom resolver that would get the list of names to resolve, > resolve each one, and return the combined list of addresses to the > channel. But I'd recommend against this approach, for the following > reasons: > > - It's a much hackier solution than simply providing the addresses > under one name in your name service. This is exactly the problem that a > name service was designed to solve, so trying to solve it in a different > way seems very odd to me. > - C-core does not currently provide a public API for implementing > resolvers in wrapped languages like C#; this is something that we want to > do, but it hasn't bubbled up to the top of our priority list. You could > probably do it by writing some code against our internal C++ API, but that > API is not supported for external use and may change from version to > version, so it's not a great option right now. > > I don't think there's any reason to need a custom LB policy for this > scenario. But even if there was, C-core does not provide a public API for > implementing LB policies in wrapped languages. And unlike resolvers, this > is probably not an API that we will ever provide, because the LB policy is > in the performance-critical path, and hopping out of core and into the > wrapped language from the LB policy would kill performance. > > I hope this information is helpful. > > On Fri, Oct 23, 2020 at 10:34 AM Dapeng (Penn) Zhang <[email protected]> > wrote: > >> I believe customizing LB logic (for instance, server names grabbed from >> Zookeeper) for c#, you will need to use c-core load balancing APIs. >> >> [email protected] who can provide more guidance. >> >> On Wednesday, October 21, 2020 at 11:03:37 PM UTC-7 [email protected] >> wrote: >> >>> Thanks for the replies! the language I'm looking at right now is c#. I >>> understand retry might not fully supported yet, while still hope I can >>> understand the design correctly as the implementation will be there sooner >>> or later which follows the design idea. >>> >>> Thanks for explanation of how subchannels work with LB and name >>> resolver. However, since the doc mentioned "Thick client" load balancing >>> <https://grpc.io/blog/grpc-load-balancing/#thick-client> with gRpc is >>> supported, any recommendation how can I have a client customized LB logic >>> (for instance, server names grabbed from Zookeeper) work with gRpc client >>> LB? I guess there is something Application code can notify LB about backend >>> changes as well? like how name resolver does. If I plan to use something >>> other than name resolver to manage backend servers list? >>> >>> thanks a lot! >>> 在2020年10月22日星期四 UTC+8 上午1:44:24<[email protected] >>> <https://groups.google.com/>> 写道： >>> >>>> On Wednesday, October 21, 2020 at 1:27:27 AM UTC-7 [email protected] >>>> wrote: >>>> >>>>> To ask my question in another word. If to build a "Thick client" load >>>>> balancing <https://grpc.io/blog/grpc-load-balancing/#thick-client> with >>>>> gRpc, the client is responsible to keep track of available servers. While >>>>> when client detected available servers changed, how does it manages >>>>> corresponding SubChannels under existing Channels? I searched around docs >>>>> today again, didn't find APIs for that. I'm looking into csharp. Sorry if >>>>> I >>>>> overlooked something. >>>>> >>>>> The client's load balancer manages subchannels and shuts down old and >>>> creates new subchannels if the backend servers changed (The name resolver >>>> notifies the loadbalancer about the backend changes). The client RPC will >>>> choose one of the current list of subchannels based on the load balancing >>>> policy. You could use the grpc library built-in round-robin load balancer >>>> if you don't have special requirement. >>>> >>>> >>>> thanks a lot >>>>> >>>>> 在2020年10月19日星期一 UTC+8 下午8:07:33<li yabo> 写道： >>>>> >>>>>> While considering moving a http client/service call to using gRpc, >>>>>> I'm looking at load balancing solutions. We currently have each client >>>>>> manages a list of server names (for one service VIP) and connection >>>>>> pools. >>>>>> The server names changes from time to time, so each client has it's >>>>>> logic >>>>>> to maintain the server names list and http connection pools. >>>>>> >>>>>> If move to using gRpc, I think the easiest change regarding LB might >>>>>> be to let client fill the server names list to gRpc as Subchannels of a >>>>>> Channel to the service VIP. So that client sends request to one Channel >>>>>> and >>>>>> get requests well load balanced. Once there is changes in the client >>>>>> server >>>>>> names list, the client Application layer code goes to update Subchannels >>>>>> in >>>>>> gRpc again. >>>>>> While I'm not sure if that's a do-able or ok approach that doesn't >>>>>> violate gRpc design? >>>>>> >>>>>> managing one Channel for each server name might be a solution, but >>>>>> that possibly won't work well with gRpc retries-policy, because we hope >>>>>> the >>>>>> retry request issued by retries-policy hit another server name of the >>>>>> server-names list. >>>>>> >>>>>> Since current client self-managed server names idea works in existing >>>>>> env, we hope we don't have to setup new roll like lookaside load >>>>>> balancer >>>>>> in the cluster only for the purpose to using gRpc. Does this idea make >>>>>> sense? >>>>>> >>>>>> Thanks a lot! >>>>>> >>>>> > > -- > Mark D. Roth <[email protected]> > Software Engineer > Google, Inc. > -- You received this message because you are subscribed to the Google Groups "grpc.io" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/grpc-io/82068559-9494-48e3-adcb-65eb0ae294c1n%40googlegroups.com.
