Just tried the Mesos integration, and I’m a little disappointed.
I thought that the Mesos integration would gain the benefits of the Rancher networking, and it seems like it’s not the case.
I created a Mesos env
I installed the Marathon framework
I cannot use rancher managed network when I create a new Marathon task using a docker container
Would be nice if it could be possible 
The Marathan framework launches the containers directly on the hosts using docker by passing Rancher completely. So the networking option for these containers is NOT ‘managed’.
But we have a solution exactly for this. You have to add a label io.rancher.container.network:true while launching these containers and Rancher would know that you are asking for ‘Managed’ networking.
Please do give it a shot and let us know how it goes.
thanks for the tip, I will try that.
Now that both Mesos/Marathon and Rancher use CNI network plugins, it would be nice if Rancher could support the “USER” network mode of Mesos/Marathon