Server-template and swarm's "tasks.<service-name>"

Hi !

I’m trying to implement load balacing on a swarm service the same way it is implemented in the following article : HAProxy on Docker Swarm: Load Balancing and DNS Service Discovery - HAProxy Technologies but with the special dns tasks.<service-name> instead of the dnsrr endpoint mode.
I thought the tasks.<service-name> was behaving the same way as the dnsrr mode.

But I can’t manage to get the dns resolution to work, my config is the same as in the blog :

resolvers docker
    nameserver dns
    resolve_retries 3
    timeout resolve 1s
    timeout retry   1s
    hold other      10s
    hold refused    10s
    hold nx         10s
    hold timeout    10s
    hold valid      10s
    hold obsolete   10s


backend <service>
    balance roundrobin
    option httpchk GET /chk "HTTP/1.1\r\nHost:\ <service>"
    http-check expect string "OK"
    default-server inter 30000 rise 1 fall 3 maxconn 16 maxqueue 16
    server-template <service>- 16 tasks.<service>:3000 check resolvers docker init-addr libc,none

If I use “stack deploy” or “service restart”, the haproxy will start with resolving correctly and all my backends will be green (service/service-10 changed its IP from (none) to by DNS cache), but then, on the next check I get resolution problems (unspecified DNS error).

Is it possible to use server-template this way, or must I use the dnsrr endpoint mode ?

I’m using haproxy 2.4.9.