Docker Inspecting a running container Get specific information from a container
Example
You can get an specific information from a container by running:
docker inspect -f '<format>' <container>
For instance, you can get the Network Settings by running:
docker inspect -f '{{ .NetworkSettings }}' <container>
You can also get just the IP address:
docker inspect -f '{{ .NetworkSettings.IPAddress }}' <container>
The parameter -f means format and will receive a Go Template as input to format what is expected, but this won’t bring a beautiful return, so try:
docker inspect -f '{{ json .NetworkSettings }}' {{containerIdOrName}}
the json keyword will bring the return as a JSON.
So to finish, a little tip is to use python in there to format the output JSON:
docker inspect -f '{{ json .NetworkSettings }}' <container> | python -mjson.tool
And voila, you can query anything on the docker inspect and make it look pretty in your terminal.
It's also possible to use a utility called "jq" in order to help process docker inspect command output.
docker inspect -f '{{ json .NetworkSettings }}' aa1 | jq [.Gateway]
The above command will return the following output:
[
"172.17.0.1"
]
This output is actually a list containing one element. Sometimes, docker inspect displays a list of several elements, and you may want to refer to a specific element. For example, if Config.Env contains several elements, you can refer to the first element of this list using index:
docker inspect --format '{{ index (index .Config.Env) 0 }}' <container>
The first element is indexed at zero, which means that the second element of this list is at index 1:
docker inspect --format '{{ index (index .Config.Env) 1 }}' <container>
Using len it is possible to get the number of elements of the list:
docker inspect --format ‘{{ len .Config.Env }}’ <container>
And using negative numbers, it's possible to refer to the last element of the list:
docker inspect –format “{{ index .Config.Cmd $[$(docker inspect –format ‘{{ len .Config.Cmd }}’ <container>)-1]}}” <container>
Some docker inspect information comes as a dictionary of key:value, here is an extract of a
docker inspectof a jess/spotify running container
"Config": { "Hostname": "8255f4804dde", "Domainname": "", "User": "spotify", "AttachStdin": false, "AttachStdout": false, "AttachStderr": false, "Tty": false, "OpenStdin": false, "StdinOnce": false, "Env": [ "DISPLAY=unix:0", "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin", "HOME=/home/spotify" ], "Cmd": [ "-stylesheet=/home/spotify/spotify-override.css" ], "Image": "jess/spotify", "Volumes": null, "WorkingDir": "/home/spotify", "Entrypoint": [ "spotify" ], "OnBuild": null, "Labels": {} },
so I an get the values of the whole Config section
docker inspect -f '{{.Config}}' 825
{8255f4804dde spotify false false false map[] false false false [DISPLAY=unix:0 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin HOME=/home/spotify] [-stylesheet=/home/spotify/spotify-override.css] false jess/spotify map[] /home/spotify [spotify] false [] map[] }
but also a single field, like the value of Config.Image
docker inspect -f '{{index (.Config) "Image" }}' 825
jess/spotify
or Config.Cmd
docker inspect -f '{{.Config.Cmd}}' 825
[-stylesheet=/home/spotify/spotify-override.css]
