Docker-CE on CentOS 7

Install Docker-CE (not just “docker) to get the latest version on CentOS.

yum install -y yum-utils device-mapper-persistent-data lvm2
yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
yum makecache fast
yum install -y docker-ce
chkconfig docker on
service docker start

Update firewalld to allow host/container traffic.

Restart firewalld to pick up the changes.

# trust the docker interface
firewall-cmd --permanent --zone=trusted --change-interface=docker0
# accept IPv4 traffic
firewall-cmd --permanent --direct --add-rule ipv4 filter INPUT 4 -i docker0 -j ACCEPT
# any ports on the host you want to access from the containers (strapi port 1337 here)
firewall-cmd --permanent --zone=trusted --add-port=1337/tcp
firewall-cmd --reload
service docker restart

Create a group named “docker” and add any users that are allowed to create containers.

groupadd docker
# allow users to access docker by adding them to the docker group
# usermod -aG docker $USER

Use an entrypoint file to create an entry in /etc/hosts to point to the host. Requires ping and ip on the machine, on Debian these are found in the apt packages inetutils-ping and iproute.

#!/bin/bash

# fix for linux hosts
HOST_DOMAIN="host.docker.internal"
ping -q -c1 $HOST_DOMAIN > /dev/null 2>&1
if [ $? -ne 0 ]; then
  HOST_IP=$(ip route | awk 'NR==1 {print $3}')
  echo -e "$HOST_IP\t$HOST_DOMAIN" >> /etc/hosts
fi

exec "$@"