Devices are not passed into docker container

Hi :) I am trying to get a test configuration working, in which I need to get run a docker image, which accesses to a company VPN using OpenVPN. When I run my image directly in docker, all works fine:

$ docker run --name unv --device /dev/net/tun -d --cap-add=NET_ADMIN actifsource/ubuntu-node-vpn

Then I added this image as a runner with following configuration, using the information from you documentation :

[[runners]]
  name = "ci runner 3 on actifsource.cloud:/src/gitlab-runner"
  url = "######"
  token = "4a61223a285########428b183d68d"
  tls-ca-file = ""
  executor = "docker"
  [runners.docker]
    image = "actifsource/ubuntu-node-vpn"
    cap_add = ["NET_ADMIN"]
    extra_hosts = ["selenium.actifsource.cloud:10.8.0.1"]
    devices = ["/dev/net/tun"]
    privileged = false
    volumes = ["/cache"]

The image seems to be run, but from OpenVPN client I now get the following error:

Wed Mar 16 11:43:41 2016 ERROR: Cannot open TUN/TAP dev /dev/net/tun: No such file or directory (errno=2)
Wed Mar 16 11:43:41 2016 Exiting due to fatal error

ERROR: Build failed with: exit code 1

This is the same error message I get, when I do not pass the --device - Flag to my first run:

$ docker run --name unv --cap-add=NET_ADMIN actifsource/ubuntu-node-vpn
Wed Mar 16 12:01:25 2016 OpenVPN 2.3.2 x86_64-pc-linux-gnu [SSL (OpenSSL)] [LZO] [EPOLL] [PKCS11] [eurephia] [MH] [IPv6] built on Feb  4 2014
######
Wed Mar 16 12:01:28 2016 ERROR: Cannot open TUN/TAP dev /dev/net/tun: No such file or directory (errno=2)
Wed Mar 16 12:01:28 2016 Exiting due to fatal error

To me it seems as if the device flag is not passed to the docker run command... I am fairly new to this, so maybe I just made a stupid mistake?

Thank you very much for any help. Michael

Not sure, whether these information from docker inspect can help:

$ docker inspect runner-4a65223e-project-2-concurrent-0-cache-fd9e15c6010b97ac6ffaaf5e3df31a34
[
    {
        "Id": "9869fc0b3baf3a663a985eb1f2f67e7b13eddd828683835362428f018c404127",
        "Created": "2016-03-16T11:27:37.023329398Z",
        "Path": "/entrypoint",
        "Args": [
            "/builds/cloud"
        ],
        "State": {
            "Status": "exited",
            "Running": false,
            "Paused": false,
            "Restarting": false,
            "OOMKilled": false,
            "Dead": false,
            "Pid": 0,
            "ExitCode": 0,
            "Error": "",
            "StartedAt": "2016-03-16T11:27:37.618804657Z",
            "FinishedAt": "2016-03-16T11:27:37.673551055Z"
        },
        "Image": "sha256:046501f04ed2cc6d8c60a9e70cdd7537fc77a66d95faf19918a291b73b81de15",
        "ResolvConfPath": "/var/lib/docker/containers/9869fc0b3baf3a663a985eb1f2f67e7b13eddd828683835362428f018c404127/resolv.conf",
        "HostnamePath": "/var/lib/docker/containers/9869fc0b3baf3a663a985eb1f2f67e7b13eddd828683835362428f018c404127/hostname",
        "HostsPath": "/var/lib/docker/containers/9869fc0b3baf3a663a985eb1f2f67e7b13eddd828683835362428f018c404127/hosts",
        "LogPath": "/var/lib/docker/containers/9869fc0b3baf3a663a985eb1f2f67e7b13eddd828683835362428f018c404127/9869fc0b3baf3a663a985eb1f2f67e7b13eddd828683835362428f018c404127-json.log",
        "Name": "/runner-4a65223e-project-2-concurrent-0-cache-fd9e15c6010b97ac6ffaaf5e3df31a34",
        "RestartCount": 0,
        "Driver": "aufs",
        "MountLabel": "",
        "ProcessLabel": "",
        "AppArmorProfile": "",
        "ExecIDs": null,
        "HostConfig": {
            "Binds": null,
            "ContainerIDFile": "",
            "LogConfig": {
                "Type": "json-file",
                "Config": {}
            },
            "NetworkMode": "default",
            "PortBindings": null,
            "RestartPolicy": {
                "Name": "",
                "MaximumRetryCount": 0
            },
            "VolumeDriver": "",
            "VolumesFrom": null,
            "CapAdd": null,
            "CapDrop": null,
            "Dns": null,
            "DnsOptions": null,
            "DnsSearch": null,
            "ExtraHosts": null,
            "GroupAdd": null,
            "IpcMode": "",
            "Links": null,
            "OomScoreAdj": 0,
            "PidMode": "",
            "Privileged": false,
            "PublishAllPorts": false,
            "ReadonlyRootfs": false,
            "SecurityOpt": null,
            "UTSMode": "",
            "ShmSize": 67108864,
            "ConsoleSize": [
                0,
                0
            ],
            "Isolation": "",
            "CpuShares": 0,
            "CgroupParent": "",
            "BlkioWeight": 0,
            "BlkioWeightDevice": null,
            "BlkioDeviceReadBps": null,
            "BlkioDeviceWriteBps": null,
            "BlkioDeviceReadIOps": null,
            "BlkioDeviceWriteIOps": null,
            "CpuPeriod": 0,
            "CpuQuota": 0,
            "CpusetCpus": "",
            "CpusetMems": "",
            "Devices": null,
            "KernelMemory": 0,
            "Memory": 0,
            "MemoryReservation": 0,
            "MemorySwap": 0,
            "MemorySwappiness": -1,
            "OomKillDisable": false,
            "PidsLimit": 0,
            "Ulimits": null
        },
        "GraphDriver": {
            "Name": "aufs",
            "Data": null
        },
        "Mounts": [
            {
                "Name": "81e8d93245a121682a1f18c6d35d5e362ab6ec9e1759186aec4c11b4944e9565",
                "Source": "/var/lib/docker/volumes/81e8d93245a121682a1f18c6d35d5e362ab6ec9e1759186aec4c11b4944e9565/_data",
                "Destination": "/builds/cloud",
                "Driver": "local",
                "Mode": "",
                "RW": true,
                "Propagation": ""
            }
        ],
        "Config": {
            "Hostname": "9869fc0b3baf",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
            ],
            "Cmd": [
                "/builds/cloud"
            ],
            "Image": "sha256:046501f04ed2cc6d8c60a9e70cdd7537fc77a66d95faf19918a291b73b81de15",
            "Volumes": {
                "/builds/cloud": {}
            },
            "WorkingDir": "",
            "Entrypoint": [
                "/entrypoint"
            ],
            "OnBuild": null,
            "Labels": {
                "com.gitlab.gitlab-runner.build.before_sha": "0000000000000000000000000000000000000000",
                "com.gitlab.gitlab-runner.build.id": "43",
                "com.gitlab.gitlab-runner.build.ref_name": "master",
                "com.gitlab.gitlab-runner.build.sha": "dba1f1166ded79ab3f05914a96cda956aaf20ed6",
                "com.gitlab.gitlab-runner.cache.dir": "/builds/cloud",
                "com.gitlab.gitlab-runner.project.id": "2",
                "com.gitlab.gitlab-runner.runner.global_id": "0",
                "com.gitlab.gitlab-runner.runner.id": "4a65223e",
                "com.gitlab.gitlab-runner.runner.local_id": "0",
                "com.gitlab.gitlab-runner.type": "cache"
            }
        },
        "NetworkSettings": {
            "Bridge": "",
            "SandboxID": "######",
            "HairpinMode": false,
            "LinkLocalIPv6Address": "",
            "LinkLocalIPv6PrefixLen": 0,
            "Ports": null,
            "SandboxKey": "/var/run/docker/netns/######",
            "SecondaryIPAddresses": null,
            "SecondaryIPv6Addresses": null,
            "EndpointID": "",
            "Gateway": "",
            "GlobalIPv6Address": "",
            "GlobalIPv6PrefixLen": 0,
            "IPAddress": "",
            "IPPrefixLen": 0,
            "IPv6Gateway": "",
            "MacAddress": "",
            "Networks": {
                "bridge": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "######",
                    "EndpointID": "",
                    "Gateway": "",
                    "IPAddress": "",
                    "IPPrefixLen": 0,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": ""
                }
            }
        }
    }
]