I want to create a Docker container for my scientific computing project. For this project I need to experiment with some dependencies, so it would be efficient if I access the shell of the container and install various packages and then choose some of them. Also, I want different people to reproduce my work and understand how I setup the environment. So, if possible, I want to make a file which is like a recipe for reproducing the same container. Should I just handwrite a text file listing what dependencies I chose at the end, or is there a tool in Docker which records automatically what packages are installed in the container after its creation?
I am not aware of any Docker tool to save the list of dependencies you install automatically. To make it easier to reproduce your exact container, you should follow the advice of #lastr2d2: record the packages you install and convert to a RUN apt-get install -y package1 package2 ... line in your Dockerfile. You could also use apt list --installed to list what you have installed, although you'll get a LOT of other packages you didn't manually install as well.
An alternative way would be to use docker commit to save the state of a running container and pushing the image to Docker Hub. The commit commands will create a Docker image of the current state of your container. These docs provide details about this command.
Important Note: If you choose to do this, please read the warnings about using docker commit. In this answer, the author points out you should not use docker commit at all because the container isn't completely reproducible.
If you've read this warning and still want to use docker commit, here's an example:
# run the container to install packages
$ docker run -it --name container-to-commit ubuntu:20.04 /bin/bash
## inside Docker terminal session
# install packages here
$ apt-get update
$ apt-get install gcc ...
To save the container, you need to keep it running and run docker commit CONTAINER_ID in another terminal. For example:
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
a26092c038ab ubuntu:20.04 "/bin/bash" 56 seconds ago Up 55 seconds container-to-commit
# commit the image with the label "username/container-name"
# username should be your Docker Hub username if you choose to distribute on Docker Hub
$ docker commit a26092c038ab username/container-name:v1
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
username/container-name v1 4752ae644acf 5 seconds ago 523MB
I would like to create a minimalist dev environment for occasional developers which only need Docker.
The ecosystem would have:
code-server image to run Visual Studio Code
gcc image to build the code
git to push/commit the code
ubuntu with some modifications to run the code
I looked to docker-in-docker which could be a solution:
Docker
code-server
docker run -it -v ... gcc make
docker run -it -v ... git git commit ...
docker run -it -v ... ubuntu ./program
But it seems perhaps a bit overkill. What would be the proper way to have a full dev environment well separated, that only require Docker to be installed on the host machine (Linux, Windows, MacOS, Chromium)
I suggest using a Dockerfile.
This file specifies a few steps used to build an image.
The first line of the file specifies a base image(in your case, I would use Ubuntu):
FROM ubuntu:latest
Then, you can e.g. copy files to the image or select commands to run:
RUN apt install gcc make
RUN apt install git
and so on.
At the end, you may want to specify the program that is run when you start the container
CMD /bin/bash
Then you can build it with the command docker build -f Dockerfile -t devenv:latest. This builds a new image named devenv:latest (latest is the version) from the file Dockerfile.
Then, you can create a container from the file using docker run devenv:latest.
If you want to use this container multiple times, you could create it using docker run -it devenv:latest
If you want to, you can also use the code-server base image instead of ubuntu:latest.
I am a novice to docker.
I am having difficulty using tensorflow docker in my Windows 10 OS.
As I am following the Udacity's deep learning course, I've downloaded the tensorflow docker following the instruction and tried to launch the first assignment.
But it failed to launch as the docker image was missing the scikit-learn package.
So basically what I do to overcome this issue is I first run my docker image:
docker run -it -p 8888:8888 b.gcr.io/tensorflow/tensorflow /bin/bash
and then I run:
pip install -U scikit-learn
and then I run (might not be 100% correct but something like):
./run_jupyter.sh
to launch the iPython notebook to carry on my assignment.
My question is simple:
how do I save this change that I occurred on this docker image so I don't have to repeat this step each time I have to relaunch the notebook?
Can I do this by modifying the docker configuration file?
Once your container is in the right state (scikit-learn is installed, the script is executed), stop it (docker stop) and commit it as a new image.
See docker commit in order to commit a container’s file changes or settings into a new image.
Then you can run that new image (with the same parameters as before), except the container created from that new image will have the previous steps already there.
But the other approach is to build your image from the tenserflow udacity Dockerfile.
FROM gcr.io/tensorflow/tensorflow:latest
MAINTAINER Vincent Vanhoucke <vanhoucke#google.com>
RUN pip install scikit-learn
RUN rm -rf /notebooks/*
ADD *.ipynb /notebooks/
WORKDIR /notebooks
CMD ["/run_jupyter.sh"]
That image, by default, will execute the right command.
I want to run an executable and all of its libraries from within my container. How do I do that?
For my Ubuntu 14.04 server, I can do sudo apt-get install tetex-base tetex-bin
In this case, however, someone already set up a docker container for me, and I need to be able to run the program from within the container.
I got it working with
docker exec -it containerName apt-get install tetex-base tetex-bin
See docs.
Despite Docker's Interactive tutorial and faq I lose my data when the container exits.
I have installed Docker as described here: http://docs.docker.io/en/latest/installation/ubuntulinux
without any problem on ubuntu 13.04.
But it loses all data when exits.
iman#test:~$ sudo docker version
Client version: 0.6.4
Go version (client): go1.1.2
Git commit (client): 2f74b1c
Server version: 0.6.4
Git commit (server): 2f74b1c
Go version (server): go1.1.2
Last stable version: 0.6.4
iman#test:~$ sudo docker run ubuntu ping
2013/10/25 08:05:47 Unable to locate ping
iman#test:~$ sudo docker run ubuntu apt-get install ping
Reading package lists...
Building dependency tree...
The following NEW packages will be installed:
iputils-ping
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 56.1 kB of archives.
After this operation, 143 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu/ precise/main iputils-ping amd64 3:20101006-1ubuntu1 [56.1 kB]
debconf: delaying package configuration, since apt-utils is not installed
Fetched 56.1 kB in 0s (195 kB/s)
Selecting previously unselected package iputils-ping.
(Reading database ... 7545 files and directories currently installed.)
Unpacking iputils-ping (from .../iputils-ping_3%3a20101006-1ubuntu1_amd64.deb) ...
Setting up iputils-ping (3:20101006-1ubuntu1) ...
iman#test:~$ sudo docker run ubuntu ping
2013/10/25 08:06:11 Unable to locate ping
iman#test:~$ sudo docker run ubuntu touch /home/test
iman#test:~$ sudo docker run ubuntu ls /home/test
ls: cannot access /home/test: No such file or directory
I also tested it with interactive sessions with the same result. Did I forget something?
EDIT: IMPORTANT FOR NEW DOCKER USERS
As #mohammed-noureldin and others said, actually this is NOT a container exiting. Every time it just creates a new container.
You need to commit the changes you make to the container and then run it. Try this:
sudo docker pull ubuntu
sudo docker run ubuntu apt-get install -y ping
Then get the container id using this command:
sudo docker ps -l
Commit changes to the container:
sudo docker commit <container_id> iman/ping
Then run the container:
sudo docker run iman/ping ping www.google.com
This should work.
When you use docker run to start a container, it actually creates a new container based on the image you have specified.
Besides the other useful answers here, note that you can restart an existing container after it exited and your changes are still there.
docker start f357e2faab77 # restart it in the background
docker attach f357e2faab77 # reattach the terminal & stdin
There are following ways to persist container data:
Docker volumes
Docker commit
a) create container from ubuntu image and run a bash terminal.
$ docker run -i -t ubuntu:14.04 /bin/bash
b) Inside the terminal install curl
# apt-get update
# apt-get install curl
c) Exit the container terminal
# exit
d) Take a note of your container id by executing following command :
$ docker ps -a
e) save container as new image
$ docker commit <container_id> new_image_name:tag_name(optional)
f) verify that you can see your new image with curl installed.
$ docker images
$ docker run -it new_image_name:tag_name bash
# which curl
/usr/bin/curl
In addition to Unferth's answer, it is recommended to create a Dockerfile.
In an empty directory, create a file called "Dockerfile" with the following contents.
FROM ubuntu
RUN apt-get install ping
ENTRYPOINT ["ping"]
Create an image using the Dockerfile. Let's use a tag so we don't need to remember the hexadecimal image number.
$ docker build -t iman/ping .
And then run the image in a container.
$ docker run iman/ping stackoverflow.com
There are really great answers above to the asked question. There might be no need for another answer but still I want to give my personal opinion on the topic in the simplest words possible.
Here are some points about containers & images that will help us for a conclusion:
A docker image can be:
created-from-a-given-container
deleted
used-to-create-any-number-of-containers
A docker container can be:
created-from-an-image
started
stopped
restarted
deleted
used-to-create-any-number-of-images
A docker run command does this:
Downloads an image or uses a cached image
Creates a new container out of it
Starts the container
When a Dockerfile is used to create an image:
It is already well known that the image will eventually be used to run a docker container.
After issuing docker build command, docker behind-the-scenes creates a running container with a base-file-system and follows steps inside the Dockerfile to configure that container as per the developers need.
After the container is configured with specs of the Dockerfile, it will be committed as an image.
The image gets ready to rock & roll!
Conclusion:
As we can see, a docker container is independent of a docker image.
A container can be restarted provided the unique ID of that container [use docker ps --all to get the id].
Any operation like making a new directory, creating files, installing tools, etc. can be done inside the container when it is running. Once the container is stopped, it persists all the changes. Container stopping and restarting is like rebooting a computer system.
An already created container is always available for a restart but when we issue docker run command, a new container is created out of an image and hence it is like a new computer system. The changes made inside the old container - as we can understand now - are not available in this new container.
A final note:
I guess it's now obvious why the data seems to be lost yet it is always there.. but in a different [old] container. So, take a good note of the difference in docker start & docker run command & never get confused in them.
I have got a much simpler answer to your question, run the following two commands
sudo docker run -t -d ubuntu --name mycontainername /bin/bash
sudo docker ps -a
the above ps -a command returns a list of all containers. Take the name of the container which references the image name - 'ubuntu' . docker auto generates names for the containers for example - 'lightlyxuyzx', that's if you don't use the --name option.
The -t and -d options are important, the created container is detached and can be reattached as given below with the -t option.
With --name option, you can name your container in my case 'mycontainername'.
sudo docker exec -ti mycontainername bash
and this above command helps you login to the container with bash shell. From this point on any changes you make in the container is automatically saved by docker.
For example - apt-get install curl inside the container
You can exit the container without any issues, docker auto saves the changes.
On the next usage, All you have to do is, run these two commands every time you want to work with this container.
This Below command will start the stopped container:
sudo docker start mycontainername
sudo docker exec -ti mycontainername bash
Another example with ports and a shared space given below:
docker run -t -d --name mycontainername -p 5000:5000 -v ~/PROJECTS/SPACE:/PROJECTSPACE 7efe2989e877 /bin/bash
In my case:
7efe2989e877 - is the imageid of a previous container running
which I obtained using
docker ps -a
You might want to look at docker volumes if you you want to persist the data in your container. Visit https://docs.docker.com/engine/tutorials/dockervolumes/. The docker documentation is a very good place to start
My suggestion is to manage docker, with docker compose. Is an easy to way to manage all the docker's containers for your project, you can map the versions and link different containers to work together.
The docs are very simple to understand, better than docker's docs.
Docker-Compose Docs
Best
the similar problem (and no way Dockerfile alone could fix it) brought me to this page.
stage 0:
for all, hoping Dockerfile could fix it: until --dns and --dns-search will appear in Dockerfile support - there is no way to integrate intranet based resources into.
stage 1:
after building image using Dockerfile (by the way it's a serious glitch Dockerfile must be in the current folder), having an image to deploy what's intranet based, by running docker run script. example:
docker run -d \
--dns=${DNSLOCAL} \
--dns=${DNSGLOBAL} \
--dns-search=intranet \
-t pack/bsp \
--name packbsp-cont \
bash -c " \
wget -r --no-parent http://intranet/intranet-content.tar.gz \
tar -xvf intranet-content.tar.gz \
sudo -u ${USERNAME} bash --norc"
stage 2:
applying docker run script in daemon mode providing local dns records to have ability to download and deploy local stuff.
important point: run script should be ending with something like /usr/bin/sudo -u ${USERNAME} bash --norc to keep container running even after the installation scripts finishes.
no, it's not possible to run container in interactive mode for the full automation matter as it will remain inside internal shall command prompt until CTRL-p CTRL-q being pressed.
no, if interacting bash will not be executed at the end of the installation script, the container will terminate immediately after finishes script execution, loosing all installation results.
stage 3:
container is still running in background but it's unclear whether container has ended installation procedure or not yet. using following block to determine execution procedure finishes:
while ! docker container top ${CONTNAME} | grep "00[[:space:]]\{12\}bash \--norc" -
do
echo "."
sleep 5
done
the script will proceed further only after completed installation. and this is the right moment to call: commit, providing current container id as well as destination image name (it may be the same as on the build/run procedure but appended with the local installation purposes tag. example: docker commit containerID pack/bsp:toolchained.
see this link on how to get proper containerID
stage 4: container has been updated with the local installs as well as it has been committed into newly assigned image (the one having purposes tag added). it's safe now to stop container running. example: docker stop packbsp-cont
stage5: any moment the container with local installs require to run, start it with the image previously saved.
example: docker run -d -t pack/bsp:toolchained
a brilliant answer here How to continue a docker which is exited from user kgs
docker start $(docker ps -a -q --filter "status=exited")
(or in this case just docker start $(docker ps -ql) 'cos you don't want to start all of them)
docker exec -it <container-id> /bin/bash
That second line is crucial. So exec is used in place of run, and not on an image but on a containerid. And you do it after the container has been started.
None of the answers address the point of this design choice. I think docker works this way to prevent these 2 errors:
Repeated restart
Partial error