sudo vim Dockerfile

====

FROM centos:centos6
MAINTAINER vagrant
RUN yum install -y passwd sudo openssh-server  
RUN useradd docker; passwd -f -u docker;
RUN mkdir -p /home/docker/.ssh; chown docker /home/docker/.ssh; chmod 700 /home/docker/.ssh  
RUN echo "ssh-rsa " >> /home/docker/.ssh/authorized_keys  
RUN chown docker /home/docker/.ssh/authorized_keys;  chmod 600 /home/docker/.ssh/authorized_keys
RUN echo "docker    ALL=(ALL)       ALL" >> /etc/sudoers.d/docker
RUN sed -ri 's/#PermitRootLogin yes/PermitRootLogin yes/g' /etc/ssh/sshd_config
RUN sed -ri 's/UsePAM yes/#UsePAM yes/g' /etc/ssh/sshd_config
RUN sed -ri 's/#UsePAM no/UsePAM no/g' /etc/ssh/sshd_config
RUN /etc/init.d/sshd start

====

sudo yum install docker
sudo service docker start
sudo docker images | awk '{print $3}' | xargs docker rmi
sudo docker build -t centos:build .
sudo docker images
sudo docker run -i -t -d -p 22 centos:build /usr/sbin/sshd -D
sudo docker ps #ポート確認
ssh -l docker -p ${PORTS} -i /home/vagrant/.ssh/id_rsa localhost