Add Dockerfile for ubuntu-disco-systemd-docker image

Author: rodnymolina

dockerfiles/ubuntu-disco-systemd-docker/Dockerfile

@@ -0,0 +1,63 @@
+#
+# Ubuntu Disco + Systemd + Sshd + Docker
+#
+# Usage:
+#
+# $ docker run --runtime=sysbox-runc -it --rm -P --name=syscont nestybox/ubuntu-disco-systemd-docker
+#
+# This will run systemd and prompt for a user login; the default
+# user/password in this image is "admin/admin". Once you log in you
+# can run Docker inside as usual. You can also ssh into the image:
+#
+# $ ssh admin@<host-ip> -p <host-port>
+#
+# where <host-port> is chosen by Docker and mapped into the system container's sshd port.
+#
+
+FROM nestybox/ubuntu-disco-systemd:latest
+
+# Docker install
+RUN apt-get update && apt-get install --no-install-recommends -y      \
+       apt-transport-https                                            \
+       ca-certificates                                                \
+       curl                                                           \
+       gnupg-agent                                                    \
+       software-properties-common &&                                  \
+                                                                      \
+    curl -fsSL https://download.docker.com/linux/ubuntu/gpg           \
+         | apt-key add - &&                                           \
+	                                                              \
+    apt-key fingerprint 0EBFCD88 &&                                   \
+                                                                      \
+    add-apt-repository                                                \
+       "deb [arch=amd64] https://download.docker.com/linux/ubuntu     \
+       $(lsb_release -cs)                                             \
+       stable" &&                                                     \
+                                                                      \
+    apt-get update && apt-get install --no-install-recommends -y      \
+       docker-ce docker-ce-cli containerd.io &&                       \
+                                                                      \
+    # Housekeeping
+    apt-get clean -y &&                                               \
+    rm -rf                                                            \
+       /var/cache/debconf/*                                           \
+       /var/lib/apt/lists/*                                           \
+       /var/log/*                                                     \
+       /tmp/*                                                         \
+       /var/tmp/*                                                     \
+       /usr/share/doc/*                                               \
+       /usr/share/man/*                                               \
+       /usr/share/local/* &&                                          \
+                                                                      \
+    # Add user "admin" to the Docker group
+    usermod -a -G docker admin
+
+# Sshd install
+RUN apt-get update && apt-get install --no-install-recommends -y      \
+            openssh-server &&                                         \
+    mkdir /home/admin/.ssh
+
+EXPOSE 22
+
+# Set systemd as entrypoint.
+ENTRYPOINT [ "/sbin/init" ]