Fix empty IP for backend when dnsrr in Docker swarm mode

[mmatur]

What does this PR do?

Fixes #1494

Currently we don't manage DNSRR resolution mode in Docker swarm mode. This PR only excludes services with DNSRR resolution mode.

We will try to implement DNSRR resolution mode in Docker swarm mode ASAP

More

• Added/updated tests

[nmengin]

LGTM 👏 👏

[ldez]

LGTM

[juliens]

LGTM

[kevtainer]

We will try to implement DNSRR resolution mode in Docker swarm mode ASAP

is there an issue being tracked for this work?

[caseycs]

Looks like the problem still exists - 1.5.2 and Docker Swarm Docker version 17.12.0-ce, build c97c6d6

deploy@www3:~$ sudo sudo ./traefik  -c traefik.sample.toml
INFO[2018-02-16T03:14:50+01:00] Using TOML configuration file /home/deploy/traefik.sample.toml
WARN[2018-02-16T03:14:50+01:00] web provider configuration is deprecated, you should use these options : api, rest provider, ping and metrics
WARN[2018-02-16T03:14:50+01:00] web option is ignored if you use it with one of these options : api, rest provider, ping or metrics
INFO[2018-02-16T03:14:50+01:00] Traefik version v1.5.2 built on 2018-02-12_10:55:08AM
...
DEBU[2018-02-16T03:14:50+01:00] Validation of load balancer method for backend backend-nginx failed: invalid load-balancing method ''. Using default method wrr.
DEBU[2018-02-16T03:14:50+01:00] Configuration received from provider docker: {"backends":{"backend-nginx":{"servers":{"server-nginx-1":{"url":"http://:80","weight":0},"server-nginx-2":{"url":"http://:80","weight":0},"server-nginx-3":{"url":"http://:80","weight":0},"server-nginx-4":{"url":"http://:80","weight":0}},"loadBalancer":{"method":"wrr"}}},"frontends":{"frontend-Host-test-test-nl-0":{"entryPoints":["http"],"backend":"backend-nginx","routes":{"route-frontend-Host-test-test-nl-0":{"rule":"Host:test.test.nl"}},"passHostHeader":true,"priority":0,"basicAuth":[]}}}
DEBU[2018-02-16T03:14:50+01:00] Creating frontend frontend-Host-test-test-nl-0
DEBU[2018-02-16T03:14:50+01:00] Wiring frontend frontend-Host-test-test-nl-0 to entryPoint http
DEBU[2018-02-16T03:14:50+01:00] Creating route route-frontend-Host-test-test-nl-0 Host:test.test.nl
DEBU[2018-02-16T03:14:50+01:00] Creating backend backend-nginx
DEBU[2018-02-16T03:14:50+01:00] Creating load-balancer wrr
DEBU[2018-02-16T03:14:50+01:00] Creating server server-nginx-4 at http://:80 with weight 0
DEBU[2018-02-16T03:14:50+01:00] Creating server server-nginx-2 at http://:80 with weight 0
DEBU[2018-02-16T03:14:50+01:00] Creating server server-nginx-3 at http://:80 with weight 0
DEBU[2018-02-16T03:14:50+01:00] Creating server server-nginx-1 at http://:80 with weight 0

And on the docker side:

deploy@www3:~$ sudo docker service inspect nginx
[
    {
...
            "EndpointSpec": {
                "Mode": "dnsrr"
            }
        },
...
    }
]

[mmatur]

Hi @caseycs,

Could you open a new issue with a detailed configuration please ?

• Træfik configuration
• Compose file with your stack

[caseycs]

@mmatur thanks, I tried to make it as clear as I can: #2869