i'm on mac running:
docker is configured to use the default machine with IP 192.168.99.100
For help getting started, check out the docs at https://docs.docker.com
my-mac:mydir$ docker run ubuntu /bin/bash
my-mac:mydir$
am i doing something wrong? shouldn't I get into the ubuntu shell?
By running docker run ubuntu /bin/bash, docker create a randomly-named container from the image ubuntu and runs a bash without stdin, stdout nor stderr then bash exits (right after being started).
Try at least to set a tty and interactive mode (aka foreground mode):
docker ps -a
# if not exited, stop it first
docker stop <container_id>
# remove the container which cannot be used
docker rm <container_id>
# let's try again
docker run -it --rm --name=test ubuntu bash
As commented by physincubus:
'-it' is the bit that makes it interactive,
'--rm' removes the container when you exit (so if you want to be able to exit for detach and reattach later, do not do this), and
'--name' allows you to name the container more explicitly in case you want to run multiple instances of the same container
Run it with following command
docker run -it ubuntu /bin/bash
Then you will get bash prompt of ubuntu container
Related
Let's say I have one docker container that when run it finishes with bash. So after docker run I have a bash terminal and I can put commands.
If for some reason I lost contact to this terminal (it can happen) and then in another terminal, I do docker ps, I can see the container running. However I am not "inside" the bash of this docker
Right now what I do is to delete this and then run docker run again but is there a way I can rejoin the terminal of this running container?
You can "detach" from a container without closing the program by Ctrl-P + Ctrl-Q
docker run -it -d --entrypoint sh busybox
docker attach $container_id
/ # #inside container, use Ctrl-p Ctrl-q to detach
I've created a dockerfile with various compile and build tools. The goal of the dockerimage is to standardize our development tools, and make it easy and consistent for developing.
Everything is installed.
What I am stuck on, is how to make the docker container keep running, and be able to have a bash shell to that container so that I can run, for example, make etc. ?
If I use ENTRYPOINT /bin/bash my container exits immediately. How to keep the container running?
You should use the command at run time. You run your Docker container in interatice mode (-i) and set the command to "/bin/bash":
docker run -it myDockerImage myCommandToExecuteInteractively
For instance:
docker run -it myDocker /bin/bash
Here is a real life example:
a) Pulling the most basic image
docker pull debian:jessie-slim
b) Let's have a bash there:
docker run -it debian:jessie-slim /bin/bash
c) Enjoy:
A docker container will run as long as the CMD/Entrypoint from your Dockerfile takes.
You can run your Docker container in interactive mode using switch i
sudo docker run -it --entrypoint=/bin/bash <imagename>
Example : docker run -it --entrypoint=/bin/bash ubuntu:14.04
This will start an interactive shell in your container. Your container will exit as soon as you exit that shell.
The answers from this question do not work.
The docker container always exits before I can attach or won't accept the -t flag. I could list all of the commands I've tried, but it's a combination of start exec attach with various -it flags and /bin/bash.
How do I start an existing container into bash? Why is this so difficult? Is this an "improper" use of Docker?
EDITS:
I created the container with docker run ubuntu. The information about the container: 60b93bda690f ubuntu "/bin/bash" About an hour ago Exited (0) 50 minutes ago ecstatic_euclid
First of all, a container is not a virtual machine. A container is an isolation environment for running a process. The life-cycle of the container is bound to the process running inside it. When the process exits, the container also exits, and the isolation environment is gone. The meaning of "attach to container" or "enter an container" actually means you go inside the isolation environment of the running process, so if your process has been exited, your container has also been exited, thus there's no container for you to attach or enter. So the command of docker attach, docker exec are target at running container.
Which process will be started when you docker run is configured in a Dockerfile and built into a docker image. Take image ubuntu as an example, if you run docker inspect ubuntu, you'll find the following configs in the output:
"Cmd": ["/bin/bash"]
which means the process got started when you run docker run ubuntu is /bin/bash, but you're not in an interactive mode and does not allocate a tty to it, so the process exited immediately and the container exited. That's why you have no way to enter the container again.
To start a container and enter bash, just try:
docker run -it ubuntu
Then you'll be brought into the container shell. If you open another terminal and docker ps, you'll find the container is running and you can docker attach to it or docker exec -it <container_id> bash to enter it again.
You can also refer to this link for more info.
Here is a very simple Dockerfile with instructions as comments ... launch it to spin up a running container you can exec login to
FROM ubuntu:20.04
ENV TERM linux
ENV DEBIAN_FRONTEND noninteractive
RUN apt-get update
RUN apt-get install -y
CMD ["/bin/bash"]
# ... save this file as Dockerfile then in same dir issue following
#
# docker build --tag stens_ubuntu . # creates image stens_ubuntu
#
# docker run -d stens_ubuntu sleep infinity # launches container
#
# docker ps # show running containers
#
#
# ... find CONTAINER ID from above and put into something like this
#
# docker exec -ti $( docker ps | grep stens_ubuntu | cut -d' ' -f1 ) bash # login to running container
# docker exec -ti 3cea1993ed28 bash # login to running container using sample containerId
#
A container will exit normally when it has no work to do ... if you give it no work it will exit immediately upon launch for this reason ... typically the last command of your Dockerfile is the execution of some flavor of a server which stays alive due to an internal event loop and in so doing keeps alive its enclosing container ... short of that you can mention a server executable which has been installed into the container as the final parameter of your call to
docker run -d my-image-name my-server-executable
This question is not duplicated, because I want to obtain an interactive shell without running with -it flags.
I'm moving first steps into Docker to create images only for internal use.
I start from this envirornment_full.df:
FROM ubuntu:16.04
ENTRYPOINT ["/bin/bash"]
I then build
docker rmi environment:full
docker build -t environment:full -f environment.df .
Then run
docker run environment:full
Running docker images -am I see my image
REPOSITORY TAG IMAGE ID CREATED SIZE
environment full aa91bbd39167 4 seconds ago 129 MB
So I run it
docker run environment:full
I see nothing happening ....
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
5847c0a18f30 environment:full "/bin/bash" 21 seconds ago Exited (0) 20 seconds ago admiring_mirzakhani
Also
$ docker run environment:full -ti
bash: cannot set terminal process group (-1): Inappropriate ioctl for device
bash: no job control in this shell
root#aa768a585f33:/# exit
I'd like to have the ubuntu prompt, like if I was in a SSH connection. And this without user must enter -i or -tty flags.
How can I realize this?
bash won't run at all if stdin is closed. If you don't provide the -i flag, bash will simply exit immediately. So when you...
docker run environment:full
...bash exits immediately, and so your container exits. You would see it if you ran docker ps -a, which shows container that have stopped.
bash won't give you an interactive prompt if it's not attached to a tty. So if you were to run...
coerk run -i environment:full
...you would get a bash shell, but with no prompt, or job control, or other features. You need to provide -t for Docker to allocate a tty device.
You can't get what you want without providing both the -i and -t options on the command line.
An alternative would be to set up an image that runs an ssh daemon, and have people ssh into the container. Instead of behaving "like if I was in a SSH connection", it would actually be an ssh session.
Also, note that this:
docker run environment:full -ti
Is not the same as this:
docker run -it environment:full
The former will run bash -ti inside a container, while the latter passes the -i and -t options to docker run.
If I am running Boot2Docker on windows 7, and I connect to a container by running a command like docker run -it ubuntu:14.04 /bin/bash, how can I "disconnect" from the container and return the prompt to the boot2docker images command prompt?
Ideally I'd like to know both how to kill the container, and how to push the container into the background and then return it to the foreground later.
What you seem to be looking for is the -d option for the docker run command which starts the container on background. You can then access the container easily with command like this (found from Timur Fayzrakhmanov's answer on AskUbuntu)
sudo docker exec -i -t <your_id> bash
where you replace the your_id with something like 665b4a1e17b6.