CODEWITHSUNDEEP
dockerdocker-composeubuntu-16.04
MWO
MWO

Reputation: 2806

Docker post build installations inside container

Is there a convenient way to find out all installations and changes made inside a docker container after the container was built? Because its not recommended to commit the changes to a new image, how could I easily find out all changes so that I can put them in the Dockerfile?

Upvotes: 2

Views: 1024

Answers (2)

Ben Njeri
Ben Njeri

Reputation: 644

There are different ways to get helpful information.

To get logs of a container, use docker logs command, the syntax is:

# docker logs [OPTIONS] CONTAINER

For a full list of available options, run:

# docker logs --help

You can also pipe the output of the command to tools like grep to filter output. See example below.

# docker run  -it --rm --name test ubuntu:16.04 /bin/bash
root@fde8369a7439:/# apt-get update
root@fde8369a7439:/# apt-get install nginx
root@fde8369a7439:/# apt-get install vim

Now check the logs, grep for apt-get.

# docker logs test | grep apt-get

If you want to save the logs to a file on docker host machine, use:

# docker logs test > test_logs

You can also utilize bash history of a container to pull some info on what you did:

# docker exec container cat /root/.bash_history

The docker diff command is often used to inspect changes to files or directories on a container's filesystem. It doesn’t give you exact commands you execute but modified files.

Upvotes: 2

Yuankun
Yuankun

Reputation: 7793

docker container diff is what you need: https://docs.docker.com/engine/reference/commandline/container_diff/

Upvotes: 0

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