docker

Create required directories
mkdir -p /etc/docker/nginx/{conf.d,html}

Configure nginx as webserver
cat < /etc/docker/nginx/conf.d/default.conf
server {
listen 80;
server_name _;

root /usr/share/nginx/html;
index index.html index.htm;
}
EOF

Configure nginx as proxy
cat < /etc/docker/nginx/conf.d/proxy.conf
server {
listen 80;
server_name foo.example.com;

location / {
proxy_pass http://localhost:8080/;
}
}
EOF

Create container

Start container
docker run --name=roundcube \
-e ROUNDCUBEMAIL_DEFAULT_HOST=imap.example.com \
-e ROUNDCUBEMAIL_SMTP_SERVER=smtp.example.com \
-e ROUNDCUBEMAIL_SMTP_PORT=993 \
-p 8080:80 \
-d roundcube/roundcubemail

# UI
http://SERVER_IP:8080/

Links
https://hub.docker.com/r/roundcube/roundcubemail/

Installation
https://docs.docker.com/install/linux/docker-ce/ubuntu/#set-up-the-repository
http://www.panticz.de/install-docker

Add user to docker group
sudo usermod -aG docker $USER
su - $USER

systemctl enable docker
systemctl status docker

Start all exited container
docker start $(docker ps -a -q -f status=exited)

Stop all containers
docker stop $(docker ps -a -q)

# Delete all containers
#docker stop $(docker ps -a -q)
docker rm $(docker ps -a -q) -f

# Delete all images