On Mon, Jul 3, 2017 at 11:52 PM, Baptiste <[email protected]> wrote: > > > On Mon, Jul 3, 2017 at 9:32 AM, Igor Cicimov <igorc@encompasscorporation. > com> wrote: > >> Hi, >> >> If I remember correctly, there was a feature that was talked about on the >> mailing list, and was said it should make it into 1.7, where the >> dns-resolver can work with dns records that return multiple IP's, like lets >> say: >> >> root@ip-10-77-0-94:~# dig +short tomcat.service.consul A >> 10.77.4.234 >> 10.77.3.227 >> >> and account for all records returned (till 1.6 the resolver was grabbing >> only the first IP returned) in terms of load balancing. So I'm testing this >> with 1.7.7 like this: >> >> >> server tomcats tomcat.service.consul:8080 check resolvers dns_resolvers >> resolve-prefer ipv4 >> >> instead of: >> >> server tomcat1 10.77.4.234:8080 check resolvers dns_resolvers >> resolve-prefer ipv4 >> server tomcat2 10.77.3.227:8080 check resolvers dns_resolvers >> resolve-prefer ipv4 >> >> to load balance between all ip's, but seeing in the logs messages like >> this: >> >> Jul 3 17:13:15 ip-10-77-0-94 haproxy[22902]: tomcats/tomcats changed its >> IP from 10.77.3.227 to 10.77.4.234 by dns_resolvers/dns0. >> >> so does this mean the feature is not implemented yet? >> >> Thanks, >> Igor >> >> > > Hi Igor, > > For now, you can't replace a couple of "hard coded" server lines by a > single server line with DNS enabled. > The second case will make you have in the end a single server in the > backend. > > HAProxy 1.8 will bring the features you need: > 1. use the server-template line to configure 2 servers (or more) in > HAProxy while using a single configuration line > 2. a cache of the DNS response has been implemented and each time a record > is used, it is internally moved to the bottom of the list, so all IPs will > be used as best as possible > > Example with server-template to apply to your example: > server-template tomcat 2 tomcat.service.consul:8080 check resolvers > dns_resolvers resolve-prefer ipv4 > > I would also recommend to set 'init-addr none' to prevent HAProxy from > using libc at configuration parsing. I saw some deployments where the host > below HAProxy was not be able to resolve an IP address from a consul > endpoint. > > Baptiste >
That's awesome, thanks Baptiste! Also appreciate the valuable input regarding consul. So excited can't wait to try this the moment 1.8 shows up in the ppa. Cheers, Igor
