Error: docker pull does not work on insecure connection by default

Solution for Centos 7: Add –insecure-registry option

1. Edit /lib/systemd/system/docker.service:

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

[Service]
EnvironmentFile=-/etc/sysconfig/docker
Type=notify
ExecStart=/usr/bin/docker daemon $other_args -H fd://
MountFlags=slave
LimitNOFILE=1048576
LimitNPROC=1048576
LimitCORE=infinity

[Install]
WantedBy=multi-user.target

2. Edit /etc/sysconfig/docker

other_args=”–insecure-registry registry_ip:port“

3. Restart docker daemon:

sudo systemctl daemon-reload
sudo service docker restart