Use this Dockerfile / -image to start a sshd-server upon a lightweight Alpine container.

• Always installs the latest OpenSSH-Version available for Alpine
• Password of "root"-user can be changed when starting the container using --env

$ docker run --rm \
--publish=1337:22 \
--env ROOT_PASSWORD=MyRootPW123 \
hermsi/alpine-sshd

After the container is up you are able to ssh in it as root with the in --env provided password for "root"-user.

$ ssh root@mydomain.tld -p 1337

I built this image in order to use it along with a nginx and fpm-php container for transferring files via sftp. If you are interested in a Dockerfile which fulfills this need: this way