Unable to see files inside a container

Question

I'm unable to access content in a container created using docker-compose; it's been suggested to me that this could be because the content folder on the host is not being mounted correctly. (Note: I don't know how to validate this advice, so I must assume that it's correct.)

Here's my docker-compose.yml file:

version: "2.1"
services:
  docs:
    image: docs/docstage
    ports:
     - "4000:4000"
    volumes:
     - "./:/usr/src/app"

Here's the output of my docker-compose command:

D:\Dev\Git\docker.github.io>docker-compose up
Creating dockergithubio_docs_1 ...
Creating dockergithubio_docs_1 ... done
Attaching to dockergithubio_docs_1
docs_1  | Configuration file: none
docs_1  | Configuration file: none
docs_1  |             Source: /usr/src/app
docs_1  |        Destination: /_site
docs_1  |  Incremental build: disabled. Enable with --incremental
docs_1  |       Generating...
docs_1  |                     done in 0.017 seconds.
docs_1  |  Auto-regeneration: enabled for '/usr/src/app'
docs_1  | Configuration file: none
docs_1  |     Server address: http://0.0.0.0:4000/
docs_1  |   Server running... press ctrl-c to stop.
docs_1  | [2017-07-17 20:58:02] ERROR `/favicon.ico' not found.

...and here's the result:

C:\Users\Admin>docker exec -it 863a59969066 bash
root@863a59969066:/usr/src/app# ls
root@863a59969066:/usr/src/app#

As we can see, there's no content in the container. Also, browsing to the URL reveals an empty directory:

Here's the result of docker container inspect:

C:\Users\Admin>docker inspect dockergithubio_docs_1
[
    {
        "Id": "863a59969066444d0b6e908a46d0f05b68605b7fe72bfd4b0ddf2036847b0779",
        "Created": "2017-07-17T20:57:06.7250794Z",
        "Path": "/bin/sh",
        "Args": [
            "-c",
            "jekyll serve -d /_site --watch -H 0.0.0.0 -P 4000"
        ],
        "State": {
            "Status": "running",
            "Running": true,
            "Paused": false,
            "Restarting": false,
            "OOMKilled": false,
            "Dead": false,
            "Pid": 3252,
            "ExitCode": 0,
            "Error": "",
            "StartedAt": "2017-07-17T20:57:08.0003358Z",
            "FinishedAt": "0001-01-01T00:00:00Z"
        },
        "Image": "sha256:9670258d73f081ef2c7dd476c56fc5945627ee68867e1296fbe19e612ddd29a4",
        "ResolvConfPath": "/var/lib/docker/containers/863a59969066444d0b6e908a46d0f05b68605b7fe72bfd4b0ddf2036847b0779/resolv.conf",
        "HostnamePath": "/var/lib/docker/containers/863a59969066444d0b6e908a46d0f05b68605b7fe72bfd4b0ddf2036847b0779/hostname",
        "HostsPath": "/var/lib/docker/containers/863a59969066444d0b6e908a46d0f05b68605b7fe72bfd4b0ddf2036847b0779/hosts",
        "LogPath": "/var/lib/docker/containers/863a59969066444d0b6e908a46d0f05b68605b7fe72bfd4b0ddf2036847b0779/863a59969066444d0b6e908a46d0f05b68605b7fe72bfd4b0ddf2036847b0779-json.log",
        "Name": "/dockergithubio_docs_1",
        "RestartCount": 0,
        "Driver": "overlay2",
        "MountLabel": "",
        "ProcessLabel": "",
        "AppArmorProfile": "",
        "ExecIDs": null,
        "HostConfig": {
            "Binds": [
                "/D/Dev/Git/docker.github.io:/usr/src/app:rw"
            ],
            "ContainerIDFile": "",
            "LogConfig": {
                "Type": "json-file",
                "Config": {}
            },
            "NetworkMode": "dockergithubio_default",
            "PortBindings": {
                "4000/tcp": [
                    {
                        "HostIp": "",
                        "HostPort": "4000"
                    }
                ]
            },
            "RestartPolicy": {
                "Name": "",
                "MaximumRetryCount": 0
            },
            "AutoRemove": false,
            "VolumeDriver": "",
            "VolumesFrom": [],
            "CapAdd": null,
            "CapDrop": null,
            "Dns": null,
            "DnsOptions": null,
            "DnsSearch": null,
            "ExtraHosts": null,
            "GroupAdd": null,
            "IpcMode": "",
            "Cgroup": "",
            "Links": null,
            "OomScoreAdj": 0,
            "PidMode": "",
            "Privileged": false,
            "PublishAllPorts": false,
            "ReadonlyRootfs": false,
            "SecurityOpt": null,
            "UTSMode": "",
            "UsernsMode": "",
            "ShmSize": 67108864,
            "Runtime": "runc",
            "ConsoleSize": [
                0,
                0
            ],
            "Isolation": "",
            "CpuShares": 0,
            "Memory": 0,
            "NanoCpus": 0,
            "CgroupParent": "",
            "BlkioWeight": 0,
            "BlkioWeightDevice": null,
            "BlkioDeviceReadBps": null,
            "BlkioDeviceWriteBps": null,
            "BlkioDeviceReadIOps": null,
            "BlkioDeviceWriteIOps": null,
            "CpuPeriod": 0,
            "CpuQuota": 0,
            "CpuRealtimePeriod": 0,
            "CpuRealtimeRuntime": 0,
            "CpusetCpus": "",
            "CpusetMems": "",
            "Devices": null,
            "DeviceCgroupRules": null,
            "DiskQuota": 0,
            "KernelMemory": 0,
            "MemoryReservation": 0,
            "MemorySwap": 0,
            "MemorySwappiness": -1,
            "OomKillDisable": false,
            "PidsLimit": 0,
            "Ulimits": null,
            "CpuCount": 0,
            "CpuPercent": 0,
            "IOMaximumIOps": 0,
            "IOMaximumBandwidth": 0
        },
        "GraphDriver": {
            "Data": {
                "LowerDir": "/var/lib/docker/overlay2/8f7ba6861640a6fb639f64c475db0260cb4c9ded686711b05625ff37c19737fa-init/diff:/var/lib/docker/overlay2/0772e69f7faba8d149e7d9aed149d4607c905f1d01b28b97f5453772e5326904/diff:/var/lib/docker/overlay2/6d2a854de0c3c7af4e8e3b6ef831af1dde8c400f5aa8fd809d76a06f3ba5c705/diff:/var/lib/docker/overlay2/8a4466b60f60d0141625c1ad32233f3fee49821f534f8709685c2d6514b9d3f6/diff:/var/lib/docker/overlay2/6a4fe33cae424e9a671300332244aa19f5a314d90c945b399f35ea487e01d333/diff:/var/lib/docker/overlay2/de35de0b23cb93e811a7f2ec6b59e3e282faf770131179c60cad588c522551be/diff:/var/lib/docker/overlay2/e7f896a4b4d0da7ddbddd208a9130affea2358f4b1fd147f403b82fe7fe748aa/diff:/var/lib/docker/overlay2/b09694bfeb6b2e7d75de351286d95bf9af18181004f9d3c2d9bf73ea6538ba56/diff:/var/lib/docker/overlay2/4feb0e4dccefd6570fee715baf80ebe6ea77ab133cc3ac15fd850bb737f7e8b2/diff:/var/lib/docker/overlay2/1291c76b0bb03c133b70dad4dd08147f3c753b52f8ac3070d2e0f9bbdd99e874/diff:/var/lib/docker/overlay2/9166f2a32c7b3284fab5a95803ac66c83cba936161083f0405b630178f5dbeb2/diff:/var/lib/docker/overlay2/46499476944e8234be84f662104f3968f8717f3e36a67bb06d814f9c70998d9f/diff:/var/lib/docker/overlay2/fc1f9d566f52e9f994bd02dd73528fb3402a98a2618c5b3a9dbf10c8c5ae554c/diff",
                "MergedDir": "/var/lib/docker/overlay2/8f7ba6861640a6fb639f64c475db0260cb4c9ded686711b05625ff37c19737fa/merged",
                "UpperDir": "/var/lib/docker/overlay2/8f7ba6861640a6fb639f64c475db0260cb4c9ded686711b05625ff37c19737fa/diff",
                "WorkDir": "/var/lib/docker/overlay2/8f7ba6861640a6fb639f64c475db0260cb4c9ded686711b05625ff37c19737fa/work"
            },
            "Name": "overlay2"
        },
        "Mounts": [
            {
                "Type": "bind",
                "Source": "/D/Dev/Git/docker.github.io",
                "Destination": "/usr/src/app",
                "Mode": "rw",
                "RW": true,
                "Propagation": "rprivate"
            }
        ],
        "Config": {
            "Hostname": "863a59969066",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "ExposedPorts": {
                "4000/tcp": {}
            },
            "Tty": false,
            "OpenStdin": false,
            "StdinOnce": false,
            "Env": [
                "PATH=/usr/local/bundle/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "RUBY_MAJOR=2.3",
                "RUBY_VERSION=2.3.3",
                "RUBY_DOWNLOAD_SHA256=241408c8c555b258846368830a06146e4849a1d58dcaf6b14a3b6a73058115b7",
                "RUBYGEMS_VERSION=2.6.8",
                "BUNDLER_VERSION=1.13.6",
                "GEM_HOME=/usr/local/bundle",
                "BUNDLE_PATH=/usr/local/bundle",
                "BUNDLE_BIN=/usr/local/bundle/bin",
                "BUNDLE_SILENCE_ROOT_WARNING=1",
                "BUNDLE_APP_CONFIG=/usr/local/bundle",
                "NPM_CONFIG_LOGLEVEL=info",
                "NODE_MAJOR_VERSION=4",
                "GITHUB_GEM_VERSION=112"
            ],
            "Cmd": [
                "/bin/sh",
                "-c",
                "jekyll serve -d /_site --watch -H 0.0.0.0 -P 4000"
            ],
            "ArgsEscaped": true,
            "Image": "docs/docstage",
            "Volumes": {
                "/usr/src/app": {}
            },
            "WorkingDir": "/usr/src/app",
            "Entrypoint": null,
            "OnBuild": null,
            "Labels": {
                "com.docker.compose.config-hash": "f86127819d2d94cf924f8d7ef0fe8579286043aebafc2940e6ca0b1d1b4828b7",
                "com.docker.compose.container-number": "1",
                "com.docker.compose.oneoff": "False",
                "com.docker.compose.project": "dockergithubio",
                "com.docker.compose.service": "docs",
                "com.docker.compose.version": "1.14.0"
            }
        },
        "NetworkSettings": {
            "Bridge": "",
            "SandboxID": "b6ad8a59f8f902f5a2fff0e4d6656bed6b3ecf1904424504886543614524f570",
            "HairpinMode": false,
            "LinkLocalIPv6Address": "",
            "LinkLocalIPv6PrefixLen": 0,
            "Ports": {
                "4000/tcp": [
                    {
                        "HostIp": "0.0.0.0",
                        "HostPort": "4000"
                    }
                ]
            },
            "SandboxKey": "/var/run/docker/netns/b6ad8a59f8f9",
            "SecondaryIPAddresses": null,
            "SecondaryIPv6Addresses": null,
            "EndpointID": "",
            "Gateway": "",
            "GlobalIPv6Address": "",
            "GlobalIPv6PrefixLen": 0,
            "IPAddress": "",
            "IPPrefixLen": 0,
            "IPv6Gateway": "",
            "MacAddress": "",
            "Networks": {
                "dockergithubio_default": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": [
                        "docs",
                        "863a59969066"
                    ],
                    "NetworkID": "8c5980632aa0810c818544573e76247a7b27f95e86d137e5f755cbff5b16b6aa",
                    "EndpointID": "ead13e880ebeede298f16c912d4eac0f5eb89ec5600da208202d54868273927d",
                    "Gateway": "172.18.0.1",
                    "IPAddress": "172.18.0.2",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:12:00:02",
                    "DriverOpts": null
                }
            }
        }
    }
]

At first glance this appears OK, but I must admit to a lack of knowledge on exactly interpreting the detail.

I've opened an issue here, but it seems I've exhausted all resources on that thread.

How can I determine whether there's a mount error occurring, and—if so—how can I fix it?

Answer 1

You need to configure docker to share your D drive into the embedded docker VM. Without that, the VM has nothing at this location and when mounting a volume in a container to a directory that doesn't exist (inside the docker VM, not on your windows machine), you get the resulting empty directory.

See the windows install steps for how to share this drive: