Fix documentation for creating containers with data volumes
The documentation for Docker 1.10.2 (API version 1.22) mentions under
the "Create a container"[1] section that `HostConfig.Binds` can be given
a "container path" which will automatically "create a new volume for the
container."
I interpreted this to mean it that the following two commands should
have the same net result:
# Create container with data volume via REST API
curl --unix-socket /var/run/docker.sock -XPOST \
http://localhost/containers/create \
-H"Content-Type: application/json" \
-d'{
"Image": "<image-id>",
...
"HostConfig": {
"Binds": [
"/some/data/volume"
]
}
}'
# Create container with data volume via CLI
docker create -v /some/data/volume <image-id> <command>
However, this turned out not the be the case, as the former would create
a mount with no source and no corresponding volume:
...
"Mounts": [
{
"Source": "",
"Destination": "/some/data/volume",
"Driver": "local",
"Mode": "",
"RW": true,
"Propagation": "rprivate"
}
],
...
"Config": {
...
"Volumes": null,
...
}
...whereas the latter would create a volume and mount it:
...
"Mounts": [
{
"Name": "9b38af46d6..."
"Source": "/var/lib/docker/volumes/9b38af46d6.../_data",
"Destination": "/some/data/volume",
"Driver": "local",
"Mode": "",
"RW": true,
"Propagation": ""
}
],
...
"Config": {
...
"Volumes": {
"/some/data/volume": {}
},
...
}
However, if you instead specify the data volume via the `Volumes` key,
then it works as expected, e.g.
curl --unix-socket /var/run/docker.sock -XPOST \
http://localhost/containers/create \
-H"Content-Type: application/json" \
-d'{
"Image": "...",
...
"Volumes": {"/some/data/volume": {}}
}'
...will create a data volume and mount it.
Thus the documentation is either incorrect, or this is a bug and the
ability to create a data volume via `HostConfig.Binds` does not
work as advertised for API version 1.22 (and likely others).
I concluded that the documentation was incorrect. Since I've only
verified this behavior for Docker 1.10.2, I updated the docs for
API versions 1.22 and 1.23, but this may apply to other versions as
well.
[1] https://docs.docker.com/engine/reference/api/docker_remote_api_v1.22/#create-a-container
Signed-off-by: Shane da Silva <shane@dasilva.io>
This commit is contained in:
parent
86ba0e29f5
commit
62fef18d69
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@ -233,6 +233,9 @@ Create a container
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"Propagation": ""
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}
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],
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"Volumes": {
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"/volumes/data": {}
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}
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"WorkingDir": "",
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"NetworkDisabled": false,
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"MacAddress": "12:34:56:78:9a:bc",
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@ -349,7 +352,6 @@ Json Parameters:
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- **StopSignal** - Signal to stop a container as a string or unsigned integer. `SIGTERM` by default.
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- **HostConfig**
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- **Binds** – A list of volume bindings for this container. Each volume binding is a string in one of these forms:
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+ `container_path` to create a new volume for the container
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+ `host_path:container_path` to bind-mount a host path into the container
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+ `host_path:container_path:ro` to make the bind-mount read-only inside the container.
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+ `volume_name:container_path` to bind-mount a volume managed by a volume plugin into the container.
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@ -467,7 +469,9 @@ Return low-level information on the container `id`
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"StdinOnce": false,
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"Tty": false,
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"User": "",
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"Volumes": null,
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"Volumes": {
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"/volumes/data": {}
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},
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"WorkingDir": "",
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"StopSignal": "SIGTERM"
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},
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@ -252,6 +252,9 @@ Create a container
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"Propagation": ""
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}
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],
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"Volumes": {
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"/volumes/data": {}
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}
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"WorkingDir": "",
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"NetworkDisabled": false,
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"MacAddress": "12:34:56:78:9a:bc",
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@ -368,7 +371,6 @@ Json Parameters:
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- **StopSignal** - Signal to stop a container as a string or unsigned integer. `SIGTERM` by default.
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- **HostConfig**
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- **Binds** – A list of volume bindings for this container. Each volume binding is a string in one of these forms:
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+ `container_path` to create a new volume for the container
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+ `host_path:container_path` to bind-mount a host path into the container
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+ `host_path:container_path:ro` to make the bind-mount read-only inside the container.
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+ `volume_name:container_path` to bind-mount a volume managed by a volume plugin into the container.
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@ -486,7 +488,9 @@ Return low-level information on the container `id`
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"StdinOnce": false,
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"Tty": false,
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"User": "",
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"Volumes": null,
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"Volumes": {
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"/volumes/data": {}
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},
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"WorkingDir": "",
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"StopSignal": "SIGTERM"
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},
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