On Tue, Jan 31, 2017 at 10:11 AM, Eric Anderson <ej...@google.com> wrote:
> On Fri, Jan 27, 2017 at 3:41 PM, Mark D. Roth <r...@google.com> wrote: > >> On Fri, Jan 27, 2017 at 1:31 PM, Eric Anderson <ej...@google.com> wrote: >>> >>> Case 3 as stated today (for contrasting) >>> >>> 1. client wants to connect to service.example.com >>> 2. do DNS SRV resolution for _grpclb._tcp.service.example.com; you >>> find it is a LB with name lb.example.com >>> 3. do a DNS resolution for lb.example.com, get IP 1.2.3.4 >>> 4. ask the proxy mapper about IP 1.2.3.4, it recognizes the IP as >>> the proxy and says to use "CONNECT service.example.com" via proxy IP >>> 1.2.3.4 >>> 5. connect to proxy 1.2.3.4, it performs internal resolution of >>> service.example.com and connects to one of the hosts >>> >>> That's not actually an accurate representation of how case 3 is proposed >> to work in the current document. >> > > Oh, sorry. #4 and 5 should have used lb.example.com instead of > service.example.com. That seems to be the only changes you made. > Well, I also added a few additional steps after step 5, but perhaps they are less relevant to the current discussion. > > Just thinking out loud here about whether there's another alternative -- >> this is a purely brainstorming-level idea, so please feel free to shoot >> holes in it. What if we had another type of SRV record specifically for >> HTTP CONNECT proxy use? >> > > I considered something of that ilk, but wasn't very excited. I do agree it > could work. I don't think we want a separate SRV for it, because that means > another lookup for *all* clients for this one rare case. > > But maybe we could shoe-horn it somewhere. Like service config. Probably > icky. > > This does have the advantage that it can be rolled out seemlessly, without > an update to the client. > > >> 1. client wants to connect to service.example.com >> 2. do DNS SRV resolution for _grpclb._tcp.service.example.com; you >> find it is a LB with name lb.example.com >> 3. do DNS SRV resolution for _grpc_proxy._tcp.lb.example.com; you >> find it is a proxy with name proxy.example.com >> >> Whoa. So do a SRV for the *LB*. I didn't quite expect that as it goes a > bit against normal SRV, but it makes sense. It's interesting. Again, for > reasons above, I don't think we want to go with this, but it does seem like > it could work. > Yeah, it seems a bit unnecessarily complex to me, too. So I think this leaves us with the current design. I've added a note to the doc explaining the need for coordination between the resolver and the proxy mapper for case 3. -- Mark D. Roth <r...@google.com> 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 grpc-io+unsubscr...@googlegroups.com. To post to this group, send email to grpc-io@googlegroups.com. Visit this group at https://groups.google.com/group/grpc-io. To view this discussion on the web visit https://groups.google.com/d/msgid/grpc-io/CAJgPXp7OaXo30cbX-Y8xR%2Bnkvm1%2Bm20zCD_pdnHJ-Ov5A_Dcjg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
