Another consideration is: has DNS been updated the reflect the new servers's IPs? The way things work is:
- (DNS) names such as foo.com resolve to a set of ip addresses - LB policies are created over the set of ip addresses (internally there's one subchannel per ip) - If all subchannels go into shutdown (eg when all servers die), the LB policy will also die. This will result in a request for re-resolution of the name under which the channel was created (in this case, the DNS name). A new LB policy will be created from the results of this re-resolution. Which is why, if 1) port numbers change (DNS doesn't provide port information) and/or 2) DNS doesn't resolve to the servers's new addresses, the new LB policy won't contain valid subchannels. On Wednesday, 1 November 2017 16:48:15 UTC-7, David Garcia Quintas wrote: > > Hi Daniel, > > Do the port numbers of the server also change? If not, it'd be helpful if > you could provide me with the logs produced when run with the following > environment variables set: GRPC_VERBOSITY=debug > GRPC_TRACE=client_channel,round_robin > > On Thursday, 26 October 2017 13:01:17 UTC-7, [email protected] wrote: >> >> Hi Michael, >> >> On Friday, October 27, 2017 at 5:03:33 AM UTC+13, Michael Lumish wrote: >>> >>> To clarify, are you saying that after your client loses its connection >>> to every server, it never reestablishes a connection with any of them? >>> >>>> >>>> >> Yes, exactly. >> >> I have a small project and a bash script that that demonstrates this. If >> you've got a Linux/Mac with nodejs and docker running in swarm mode, I can >> share it with you. Essentially it starts 1 client and 2 server instances >> (the client just sends a 'ping' request every 2 seconds the server just >> sends a response indicating which server responded) all runs well and shows >> load balancing between them. Then the script shuts down both instances of >> the server and starts them up again in a way to force them to have >> different IP addresses. The client is never able to reconnect with the 2 >> new instances on the different IP addresses. >> >> Regards, >> Daniel >> > -- 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 post to this group, send email to [email protected]. 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/4f3ea268-dddd-4334-90b1-99ebe1fd5e8c%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
