docker inspect
| Description | Return low-level information on Docker objects |
|---|---|
| Usage | docker inspect [OPTIONS] NAME|ID [NAME|ID...] |
Description
Docker inspect provides detailed information on constructs controlled by Docker.
By default, docker inspect will render results in a JSON array.
Format the output (--format)
If a format is specified, the given template will be executed for each result.
Go's text/template package describes all the details of the format.
Specify target type (--type)
--type container|image|node|network|secret|service|volume|task|plugin
The docker inspect command matches any type of object by either ID or name. In
some cases multiple type of objects (for example, a container and a volume)
exist with the same name, making the result ambiguous.
To restrict docker inspect to a specific type of object, use the --type
option.
The following example inspects a volume named myvolume.
$ docker inspect --type=volume myvolume
Inspect the size of a container (-s, --size)
The --size, or short-form -s, option adds two additional fields to the
docker inspect output. This option only works for containers. The container
doesn't have to be running, it also works for stopped containers.
$ docker inspect --size mycontainer
The output includes the full output of a regular docker inspect command, with
the following additional fields:
SizeRootFs: the total size of all the files in the container, in bytes.SizeRw: the size of the files that have been created or changed in the container, compared to it's image, in bytes.
$ docker run --name database -d redis
3b2cbf074c99db4a0cad35966a9e24d7bc277f5565c17233386589029b7db273
$ docker inspect --size database -f '{{ .SizeRootFs }}'
123125760
$ docker inspect --size database -f '{{ .SizeRw }}'
8192
$ docker exec database fallocate -l 1000 /newfile
$ docker inspect --size database -f '{{ .SizeRw }}'
12288
Options
| Option | Default | Description |
|---|---|---|
-f, --format | Format output using a custom template: 'json': Print in JSON format 'TEMPLATE': Print output using the given Go template. Refer to https://docs.docker.com/go/formatting/ for more information about formatting output with templates | |
-s, --size | Display total file sizes if the type is container | |
--type | Return JSON for specified type |
Examples
Get an instance's IP address
For the most part, you can pick out any field from the JSON in a fairly straightforward manner.
$ docker inspect --format='{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $INSTANCE_ID
Get an instance's MAC address
$ docker inspect --format='{{range .NetworkSettings.Networks}}{{.MacAddress}}{{end}}' $INSTANCE_ID
Get an instance's log path
$ docker inspect --format='{{.LogPath}}' $INSTANCE_ID
Get an instance's image name
$ docker inspect --format='{{.Config.Image}}' $INSTANCE_ID
List all port bindings
You can loop over arrays and maps in the results to produce simple text output:
$ docker inspect --format='{{range $p, $conf := .NetworkSettings.Ports}} {{$p}} -> {{(index $conf 0).HostPort}} {{end}}' $INSTANCE_ID
Find a specific port mapping
The .Field syntax doesn't work when the field name begins with a number, but
the template language's index function does. The .NetworkSettings.Ports
section contains a map of the internal port mappings to a list of external
address/port objects. To grab just the numeric public port, you use index to
find the specific port map, and then index 0 contains the first object inside
of that. Then, specify the HostPort field to get the public address.
$ docker inspect --format='{{(index (index .NetworkSettings.Ports "8787/tcp") 0).HostPort}}' $INSTANCE_ID
Get a subsection in JSON format
If you request a field which is itself a structure containing other fields, by
default you get a Go-style dump of the inner values. Docker adds a template
function, json, which can be applied to get results in JSON format.
$ docker inspect --format='{{json .Config}}' $INSTANCE_ID