Parallel container can not resolve dns

[Ulli2k]

I have successfully installed pi hole in my docker environment by the provided docker-compose. Due to my ubuntu system I also followed the ubuntu procedure about resolve.conf.

This is a Issue trying to run the docker image

Description

Parallel docker container which are using the internet/DNS resolution are not working.
If I try to resolve an DNS on the basis system...outside of any container it works.
But inside of any container it is not working.
On all my other devices/computer the dns resolution works fine so far.

I have tried destroying my container instance, pulling the newest image version, and re-creating a new container
I have tried running without my volume data mounts to eliminate volumes as the cause
I have searched this repository for existing issues and pull requests that look similar

Context and extra information

Your Environment

• Docker Host Operating System and OS Version: ubuntu current lts
• Docker Version:
• Hardware architecture: x86

[jokaorgua]

I have the same issue on Raspberry PI 4

[conrad82]

Did you find any solutions?

[edgd1er]

Hi All,

May be the setup you have, is the same I have.
I'm running on my Rpi 4, next to the pihole container, containers that need dns resolution ( socks5 server, yacht, watchtower, ..).
I need those containers to have a proper dns resolution and it seems that docker is not good at it when the dns server is amongst its containers.
Her is my solution:
for each container

• attached the container to pihole's network
• add a dns that is pihole's net gateway ( docker network inspect | grep -i gateway )

as a result I add in the docker-compose of each container that needs dns resolution:

services:
 service1:
    ......
    networks:
      - pihole_net
    dns:
      - 172.27.0.1

networks:
  pihole_net:
    external: true

I hope it helps.

[conrad82]

@edgd1er , thank you!

That worked for me!

I was a bit lazy, so I have not created a pihole_net network.
I used the default docker-compose network gateway, docker network inspect <default network> | grep -i gateway.
I did a reboot to see if it changed, it seemed to be persistent across a single reboot at least

I also tried

dns:
      - 1.1.1.1

which also works, for the superlazy - but it then bypasses pihole.

In summary, in my single docker-compose.yml with pihole and other containers, I

1. Found the docker gateway ip address in accordance with solution from @edgd1er
2. Added following to .env file: GATEWAY=172.18.0.1 # sudo docker network inspect docker-server_default | grep -i gateway
3. For containers requiring internet, I added

    dns:
      - $GATEWAY

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