How to run packer on Apple Silicon machine to create an image targeting x86 server

Set this environment variable before running packer command. 

DOCKER_DEFAULT_PLATFORM=linux/amd64

Add local registry mirror to docker daemon on systemd ubuntu (after 15.04)

After docker installation, follow this steps

• Create directory /etc/systemd/system/docker.service.d if not exist
• Create mirror.conf file inside that directory. The name "mirror" can be changed to anything.
• In the file, add this lines

[Service]

ExecStart=

ExecStart=/usr/bin/docker daemon -H fd:// --registry-mirror=http://registry-host:registry-port

• registry-host is hostname/ip of your local registry mirror
• registry-port is port of your local registry mirror
• Flush the change with $ sudo systemctl daemon-reload
• Restart docker with $ sudo systemctl restart docker
• Check if the change is successfully applied with $ systemctl status docker,  your config should appear somewhere in the command output.

Tested on Docker 1.11, Ubuntu 15.10 & 16.04

If you want more explanations about these commands, please refer to follow links. Thank you for all of them for providing me a direction to solve the issue and also come up with this post.

• Control and configure Docker with systemd
• How to configure Docker on Ubuntu 15.04 (workaround)
• Run a local registry mirror

Delete unused (orphaned) Docker volume

Since Docker 1.9, there's an easy way to find unused volumes and delete them.

To list unused volumes, use this command

$ docker volume ls -qf dangling=true

To delete them, use

$ docker volume rm $(docker volume ls -qf dangling=true)

Credit: I copied the whole thing from this SO answer

Set daemon config for Docker for Mac

Just follow what describe in this link How to run a insecure-registry

Capture the screen in case the link is gone in the future

Set bash completion when aliasing docker to d

After you installed docker bash completion, either by sourcing it from your .bash_profile or installing it to bash-completion, add this line to the end of your docker-completion.sh file.

complete -F _docker d

Reload your shell. And that's it!

Note: change the last d to other character you aliased docker to

[Docker] Look inside running container

docker exec -t -i <container-name> /bin/bash

For looking inside an image, use

docker run -t -i <image-name> /bin/bash

credit: http://stackoverflow.com/a/20816397