Container not running – CentOS

start with an empty dir and put following in that dir as a file called Dockerfile

FROM centos

RUN yum -y install openssh-server 
RUN yum install -y passwd 
RUN useradd remote_user

RUN echo "1234" | passwd remote_user --stdin 

RUN mkdir /home/remote_user/.ssh


RUN chmod 700 /home/remote_user/.ssh

COPY remote_user.pub /home/remote_user/.ssh/authorized_keys
RUN chown remote_user:remote_user -R /home/remote_user 

RUN chmod 400 /home/remote_user/.ssh/authorized_keys
CMD /usr/sbin/sshd -D


# CMD ["/bin/bash"]


# ... save this file as Dockerfile then in same dir issue following
#
# docker build --tag stens_centos .   # creates image stens_ubuntu
#
# docker run -d  stens_centos  sleep infinity # launches container and just sleeps only purpose here is to keep container running
#
# docker ps     #   show running containers
#
# 
# ... find CONTAINER ID from above and put into something like this
#
# docker exec -ti $( docker ps | grep stens_centos | cut -d' ' -f1 ) bash   #  login to running container
#

then in that same dir put your ssh key files as per

eve@milan ~/Dropbox/Documents/code/docker/centos $ ls -la
total 28
drwxrwxr-x  2 eve eve  4096 Nov  2 15:20 .
drwx------ 77 eve eve 12288 Nov  2 15:14 ..
-rw-rw-r--  1 eve eve   875 Nov  2 15:20 Dockerfile
-rwx------  1 eve eve  3243 Nov  2 15:18 remote_user
-rwx------  1 eve eve   743 Nov  2 15:18 remote_user.pub

then cat out Dockerfile and copy and paste commands it explains at bottom of Dockerfile file … for me all of them just worked OK

after I copy and pasted those commands listed at bottom of Dockerfile the container gets built and executed

docker ps
  
CONTAINER ID   IMAGE          COMMAND            CREATED         STATUS         PORTS     NAMES
0a06ebd2752a   stens_centos   "sleep infinity"   7 minutes ago   Up 7 minutes             pedantic_brahmagupta

keep in mind you must define in your Dockerfile the bottom CMD or similar to be just what you want to get executed as the container runs which typically is a server which by definition runs forever … alternatively this CMD can be simply something which runs then finishes like a batch job in which case the container will exit when that job finishes … with this knowledge I suggest you confirm sshd -D will hold that command as a server or will immediately terminate upon launch of container