From one remote host to another remote host, connecting to them through SSH.
ssh <SOURCE_SSH_HOST> 'docker run --rm -v <SOURCE_DATA_VOLUME_NAME>:/from alpine ash -c "cd /from ; tar -cf - . " ' | ssh <TARGET_SSH_HOST> 'docker run --rm -i -v <TARGET_DATA_VOLUME_NAME>:/to alpine ash -c "cd /to ; tar -xpvf - " '