How to use volumes-from in marathon

Question

I'm working with mesos + marathon + docker quite a while but I got stuck at some point. At the moment I try to deal with persistent container and I tried to play around with the "volumes-from" parameter but I can't make it work because I have no clue how I can figure out the name of the data box to put it as a key in the json. I tried it with the example from here

    {
    "id": "privileged-job",
    "container": {
        "docker": {
            "image": "mesosphere/inky"
            "privileged": true,
            "parameters": [
                { "key": "hostname", "value": "a.corp.org" },
                { "key": "volumes-from", "value": "another-container" },
                { "key": "lxc-conf", "value": "..." }
            ]
        },
        "type": "DOCKER",
        "volumes": []
    },
    "args": ["hello"],
    "cpus": 0.2,
    "mem": 32.0,
    "instances": 1
}

I would really appreciate any kind of help :-)

Answer 1

From what I know : docker --volume-from take the ID or the name of a container.

Since your datacontainer is launch with Marathon too, it get an ID (not sur how to get this ID from marathon) and a name of that form : mesos-0fb2e432-7330-4bfe-bbce-4f77cf382bb4 which is not related to task ID in Mesos nor docker ID.

The solution would be to write something like this for your web-ubuntu application :

"parameters": [
    { "key": "volumes-from", "value": "mesos-0fb2e432-7330-4bfe-bbce-4f77cf382bb4" }
]

Since this docker-ID is unknown from Marathon it is not practical to use datacontainer that are started with Marathon.

You can try to start a datacontainer directly with Docker (without using Marathon) and use it as you do before but since you don't know in advance where web-ubuntu will be scheduled (unless you add a constraint to force it) it is not practical.