Centos7 and naked docker

all.network

[Match]
Name=en*

[Network]
DHCP=yes

build.sh

#!/bin/bash

docker build --build-arg=http_proxy=http://172.17.0.1:3128 \
    --build-arg=https_proxy=http://172.17.0.1:3128 -t zbi/centos7 dockerfile

docker.repo

[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/main/centos/7/
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg

docker.service

[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
After=network.target docker.socket
Requires=docker.socket

[Service]
Type=notify
EnvironmentFile=-/etc/default/docker
ExecStart=/usr/bin/docker daemon -H fd:// -H tcp://0.0.0.0:2375 \
    --storage-driver overlay \
    --cluster-store etcd://localhost:2379 \
    --log-driver journald
MountFlags=slave
LimitNOFILE=1048576
LimitNPROC=1048576
LimitCORE=infinity

[Install]
WantedBy=multi-user.target

Dockerfile

FROM centos:7

RUN echo 'filesystems+="ext4"' > /etc/dracut.conf.d/supported_filesystems.conf

RUN yum update -y && \
    yum install -y kernel ca-certificates \
        systemd-networkd systemd-resolved
    
RUN update-ca-trust

# Provision the basic image
COPY docker.repo /etc/yum.repos.d/docker.repo

RUN yum install -y docker-engine

COPY docker.service /etc/systemd/system/docker.service

RUN ln -sf /etc/systemd/system/docker.service \
        /etc/systemd/system/multi-user.target.wants/docker.service

RUN ln -sf /lib/systemd/system/systemd-networkd.service /etc/systemd/system/multi-user.target.wants/systemd-networkd.service ; \
    ln -sf /lib/systemd/system/systemd-resolved.service /etc/systemd/system/multi-user.target.wants/systemd-resolved.service

COPY all.network /etc/systemd/network/all.network

# Debian/Ubuntu add these by default, RedHat do not.
RUN ln -sf /boot/$(ls /boot | grep vmlinuz) /vmlinuz && \
    ln -sf /boot/$(ls /boot | grep initramfs) /initrd.img
    
RUN echo "root:guest" | chpasswd

# Enforce SELinux relabelling on first boot
RUN touch /.autorelabel