Minimal Alpine Linux Docker container with sshd exposed and rsync installed. This uses the excellent alpine-base with s6-overlay. This means
the image will correctly log, handle errors, and do other things that you'd expect a base image to be capable of.
Mount your .ssh credentials at /root/.ssh/ in order to access the container via root ssh.
Alternatively pass in your key via the AUTHORIZED_KEY env variable.
docker run --rm -it -p 2222:22 -v ~/my_ssh_keys:/root/.ssh/ gaff/alpine-sshd
docker run --rm -it -p 2222:22 -e AUTHORIZED_KEY="`cat id_rsa.pub`" gaff/alpine-sshd