moby--moby/docs/sources/articles/configuring.md

page_title: Configuring Docker page_description: Configuring the Docker daemon on various distributions page_keywords: docker, daemon, configuration

Configuring Docker on various distributions

After successfully installing the Docker daemon on a distribution, it runs with it's default config. Usually it is required to change the default config to meet one's personal requirements.

Docker can be configured by passing the config flags to the daemon directly if the daemon is started directly. Usually that is not the case. A process manager (like SysVinit, Upstart, systemd, etc) is responsible for starting and running the daemon.

Some common config options are

• -D : Enable debug mode

• -H : Daemon socket(s) to connect to

• --tls : Enable or disable TLS authentication

The complete list of flags can found at Docker Command Line Reference

Ubuntu

After successfully installing Docker for Ubuntu, you can check the running status using (if running Upstart)

$ sudo status docker
docker start/running, process 989

You can start/stop/restart docker using

$ sudo start docker

$ sudo stop docker

$ sudo restart docker

Configuring Docker

Docker options can be configured by editing the file /etc/default/docker. If this file does not exist, it needs to be createdThis file contains a variable named DOCKER_OPTS. All the config options need to be placed in this variable. For example

DOCKER_OPTS=" --dns 8.8.8.8 -D --tls=false -H tcp://0.0.0.0:2375 "

The above daemon options :

1. Set dns server for all containers

2. Enable Debug mode

3. Set tls to false

4. Make the daemon listen for connections on tcp://0.0.0.0:2375

After saving the file, restart docker using sudo restart docker. Verify that the daemon is running with the options specified by running ps aux | grep docker | grep -v grep