b81d12e7a1
Although the example is just for illustrational purposes, many users are now switching to Ubuntu 16.04 as the "default" version for Ubuntu, so updating the example for those that use this example as a starting point. Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
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Dockerizing an SSH daemon service
Build an eg_sshd image
The following Dockerfile sets up an SSHd service in a container that you
can use to connect to and inspect other container's volumes, or to get
quick access to a test container.
FROM ubuntu:16.04
MAINTAINER Sven Dowideit <SvenDowideit@docker.com>
RUN apt-get update && apt-get install -y openssh-server
RUN mkdir /var/run/sshd
RUN echo 'root:screencast' | chpasswd
RUN sed -i 's/PermitRootLogin prohibit-password/PermitRootLogin yes/' /etc/ssh/sshd_config
# SSH login fix. Otherwise user is kicked off after login
RUN sed 's@session\s*required\s*pam_loginuid.so@session optional pam_loginuid.so@g' -i /etc/pam.d/sshd
ENV NOTVISIBLE "in users profile"
RUN echo "export VISIBLE=now" >> /etc/profile
EXPOSE 22
CMD ["/usr/sbin/sshd", "-D"]
Build the image using:
$ docker build -t eg_sshd .
Run a test_sshd container
Then run it. You can then use docker port to find out what host port
the container's port 22 is mapped to:
$ docker run -d -P --name test_sshd eg_sshd
$ docker port test_sshd 22
0.0.0.0:49154
And now you can ssh as root on the container's IP address (you can find it
with docker inspect) or on port 49154 of the Docker daemon's host IP address
(ip address or ifconfig can tell you that) or localhost if on the
Docker daemon host:
$ ssh root@192.168.1.2 -p 49154
# The password is ``screencast``.
root@f38c87f2a42d:/#
Environment variables
Using the sshd daemon to spawn shells makes it complicated to pass environment
variables to the user's shell via the normal Docker mechanisms, as sshd scrubs
the environment before it starts the shell.
If you're setting values in the Dockerfile using ENV, you'll need to push them
to a shell initialization file like the /etc/profile example in the Dockerfile
above.
If you need to passdocker run -e ENV=value values, you will need to write a
short script to do the same before you start sshd -D and then replace the
CMD with that script.
Clean up
Finally, clean up after your test by stopping and removing the container, and then removing the image.
$ docker stop test_sshd
$ docker rm test_sshd
$ docker rmi eg_sshd