Add Insecure Registry to Docker

Question

(Copying answer from question)

To add an insecure docker registry, add the file /etc/docker/daemon.json with the following content:

{
    "insecure-registries" : [ "hostname.cloudapp.net:5000" ]
}

and then restart docker.

Creating /etc/docker/daemon.json file and adding the below content and then doing a docker restart on CentOS 7 resolved the issue.

{
    "insecure-registries" : [ "hostname.cloudapp.net:5000" ]
}

The solution with the /etc/docker/daemon.json file didn't work for me on Ubuntu.

I was able to configure Docker insecure registries on Ubuntu by providing command line options to the Docker daemon in /etc/default/docker file, e.g.:

# /etc/default/docker    
DOCKER_OPTS="--insecure-registry=a.example.com --insecure-registry=b.example.com"

The same way can be used to configure custom directory for docker images and volumes storage, default DNS servers, etc..

Now, after the Docker daemon has restarted (after executing sudo service docker restart), running docker info will show:

Insecure Registries:
  a.example.com
  b.example.com
  127.0.0.0/8

For me in Ubuntu 20.04 better way is edit systemd service

/lib/systemd/system/docker.service

and add here line after [Service]

Environment=DOCKER_OPTS=--insecure-registry=10.0.0.10:6000

or it can be done automatically by 2 commands using sed, it will add the line after [Service]

sed 's/\[Service\]/\[Service\] \nEnvironment=DOCKER_OPTS=--insecure-registry=10.0.0.10:6000/' /lib/systemd/system/docker.service > /lib/systemd/system/docker.service.tmp
mv /lib/systemd/system/docker.service.tmp /lib/systemd/system/docker.service

Anyone looking to add insecure registry on amazon linux 2: You will have to change the setting under /etc/sysconfig/docker and then restart docker daemon: here's how my /etc/sysconfig/docker looks like

# The max number of open files for the daemon itself, and all
# running containers.  The default value of 1048576 mirrors the value
# used by the systemd service unit.
DAEMON_MAXFILES=1048576

# Additional startup options for the Docker daemon, for example:
# OPTIONS="--ip-forward=true --iptables=true"
# By default we limit the number of open files per container
OPTIONS="--default-ulimit nofile=1024:4096 --insecure-registry yourinsecureregistryhostname:port"

# How many seconds the sysvinit script waits for the pidfile to appear
# when starting the daemon.
DAEMON_PIDFILE_TIMEOUT=10

On Mac. source

1. Goto ~/Library/Containers/com.docker.docker/Data/database
2. There is an .git repository (.git)
3. Reset to HEAD git reset --hard
4. now you have com.docker.driver.amd64-linux folder
5. Go into ~/Library/Containers/com.docker.docker/Data/database/com.docker.driver.amd64-linux/etc/docker
6. there is your daemon.json file