Solve the DNS issue when play docker on ubuntu

Docker 在Ubuntu上面的dns问题

Issue description

Recently, I met an issue during dockerfile building. When I try to build a docker image on Ubuntu 16.04.3, it always failed. After a few checking, I found that the DNS does not work in container.

The impact is that, if my dockerfile has update actions (apt updat/apk update), it never works. In this case, I can't install any software during docker image building.

Environment

Ubuntu 16.04.3
docker-ce 17.09.0-ce

Solve docker DNS issue on ubuntu

I checked many solution online, there is a simple way to solve this.

1. Check you local DNS

nmcli dev show|grep "IP4.DNS"
IP4.DNS[1]:                             xxx.xxx.xxx.xxx

2. Create or modify /etc/docker/daemon.json

sudo vim /etc/docker/daemon.json
{
  "dns": ["xxx.xxx.xxx.xxx","8.8.8.8"]
}

3. Restart docker service

sudo service docker restart

Extend learning

How docker DNS works? see this article