Hi ! Sorry to bother you again with this question, but still i think it would be a great feature to loadbalance directly to pods from haproxy :) Is there any news on the roadmap about that ?
Regards, Smana 2015-09-22 20:21 GMT+02:00 Joseph Lynch <joe.e.ly...@gmail.com>: > Disclaimer: I help maintain SmartStack and this is a shameless plug > > You can also achieve a fast and reliable dynamic backend system by > using something off the shelf like airbnb/Yelp SmartStack > (http://nerds.airbnb.com/smartstack-service-discovery-cloud/). > > Basically there is nerve that runs on every machine healthchecking > services, and once they pass healthchecks they get registered in a > centralized registration system which is pluggable (zookeeper is the > default but DNS is another option, and we're working on DNS SRV > support). Then there is synapse which runs on every client machine and > handles re-configuring HAProxy for you automatically, handling details > like doing socket updates vs reloading HAProxy correctly. To make this > truly reliable on some systems you have to do some tricks to > gracefully reload HAProxy for picking up new backends; search for zero > downtime haproxy reloads to see how we solved it, but there are lots > of solutions. > > We use this stack at Yelp to achieve the same kind of dynamic load > balancing you're talking about except instead of kubernetes we use > mesos and marathon. The one real trick here is to use a link local IP > address and run the HAProxy/Synapse instances on the machines > themselves but have containers talk over the link local IP address. I > haven't tried it with kubernetes but given my understanding you'd end > up with the same problem. > > We plan to automatically support whichever DNS or stats socket based > solution the HAProxy devs go with for dynamic backend changes. > > -Joey > > On Fri, Sep 18, 2015 at 8:34 AM, Eduard Martinescu > <emartine...@salsalabs.com> wrote: > > I have implemented something similar to allow use to dynamically > > load-balance between multiple backends that are all joined to each other > as > > part of a Hazelcast cluster. All of which is running in an AWS VPC, with > > autoscaling groups to control spin up and down of new members of the > cluster > > based on load, etc. > > > > What we ended up doing is righting custom code that attached to the > > hazelcast cluster as a client, and periodically queried the cluster for > the > > current list of servers, and their IP addresses. The coded would then > > rewrite the HAProxy configuration, filling in the correct backend list. > > Then via a shell call (sadly, Java can't do Unix domain sockets to write > > directly to the server), it would tell HAProxy to restart gracefully. > > > > In our use case, this works great, as we don't have long-running TCP > > connections (these servers typically serve REST API calls or static HTML > > content with no keep-alive.) > > > > I'm also open to suggestions on how this could be improved too, > especially > > with 1.6 possibly. > > > > Ed > > > > ________________________________ > > ✉ Eduard Martinescu | ✆ (585) 708-9685 | - ignite action. fuel change. > > > > On Fri, Sep 18, 2015 at 9:21 AM, Baptiste <bed...@gmail.com> wrote: > >> > >> On Fri, Sep 18, 2015 at 3:18 PM, Smain Kahlouch <smain...@gmail.com> > >> wrote: > >> >> If I may chime in here: Kubernetes supports service discovery through > >> >> DNS > >> >> SRV records for most use-cases, so the dynamic DNS support that > >> >> Baptiste > >> >> is > >> >> currently working on would be a perfect fit. No special API support > >> >> required. > >> > > >> > > >> > Well dns would be great but, as far as i know, kubernetes uses dns > only > >> > for > >> > services name, not for pods. > >> > A pod can be seen as a server in a backend, the number of servers and > >> > their > >> > ip addresses can change frequently. > >> > I'll dig further... > >> > > >> > Thanks, > >> > Smana > >> > >> > >> That's usually the purpose of DNS SRV records ;) > >> > >> Baptiste > >> > > >
