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Docker: Temporary failure resolving 'deb.debian.org'

I have a Rails application that I want to deploy using Docker on an Ubuntu server. I have the Dockerfile for the application already set up, right now I want to view the nginx conf in its container.

I ran the command below to start an nginx container in an interactive mode:

docker run -i -t nginx:latest /bin/bash

Right now I am trying to install nano editor in order to view the configuration for nginx configuration (nginx.conf) using the commands below:

apt-get update
apt-get install nano
export TERM=xterm

However, when I run the first command apt-get update, I get the error below:

Err:1 http://security.debian.org/debian-security buster/updates InRelease
  Temporary failure resolving 'security.debian.org'
Err:2 http://deb.debian.org/debian buster InRelease                  
  Temporary failure resolving 'deb.debian.org'
Err:3 http://deb.debian.org/debian buster-updates InRelease
  Temporary failure resolving 'deb.debian.org'
Reading package lists... Done    
W: Failed to fetch http://deb.debian.org/debian/dists/buster/InRelease  Temporary failure resolving 'deb.debian.org'
W: Failed to fetch http://security.debian.org/debian-security/dists/buster/updates/InRelease  Temporary failure resolving 'security.debian.org'
W: Failed to fetch http://deb.debian.org/debian/dists/buster-updates/InRelease  Temporary failure resolving 'deb.debian.org'
W: Some index files failed to download. They have been ignored, or old ones used instead.

I have checked very well it has nothing to do with network connectivity. I would need some help. Thank you.

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17

Answers


  1. Chosen as BEST ANSWER
    0

    Here's how I solved it:

    Start the docker container for the application in an interactive mode, in my case it an nginx container :

    docker run -i -t nginx:latest /bin/bash

    Run the command below to grant read permission to the others role for the resolv.conf file:

    chmod o+r /etc/resolv.conf

    Note: If you are having this issue on your host machine (Ubuntu Linux OS) and not for the Docker containers, then run the same command adding sudo to it in the host machine terminal:

    sudo chmod o+r /etc/resolv.conf

    Endeavour to exit your bash interactive terminal once you run this:

    exit

    And then open a new bash interactive terminal and run the commands again:

    apt-get update
apt-get install nano
export TERM=xterm

    Everything should work fine now.

    Reference to this on Digital Ocean: Apt error: Temporary failure resolving 'deb.debian.org'

    That's all.


  2. 0

    I easily resolved it via:

    - docker exec -it nginx bash (Go inside container)
- ping google.com (if not working)
- exit (Exit from container)
- sudo service docker restart

    Please also confirms /etc/sysctl.conf

    - net.ipv4.ip_forward = 1

    sudo sysctl -p /etc/sysctl.conf

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  3. 0

    If you have VPN running, stop it and try again. It solved for me!

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  4. 0

    I had a similar issue, I tried many suggested solutions, but my issue was gone after I rebooted my VM.

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  5. 0

    Try restarting Docker.

    sudo service docker restart or sudo /etc/init.d/docker restart

    For this to work, Docker should have been working fine in the past. If you never had Docker working in the first place, you probably have a different issue.

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  6. 0

    Under Debian, as root, I’ve ran:

    /etc/init.d/docker restart

    This solved the issue for me.

    Then build and run the container again.

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  7. 0

    Perhaps the network on the VM is not communicating with the default network created by docker during the build (bridge), so try "host" network :

    docker build --network host -t [image_name]

    for docker-compose:

    service_name:
    container_name: name
    build: 
      context: .
      network: host
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  8. 0

    I had the same problem and in my case it was file access control.

    I uses extended acls on the docker root folder and did not realize it, because they where inherited from the folder above (stupid idea to test docker in a "scratch" directory where permissions are set via extended acls).

    This lead to the situation that "/etc/resolv.conf" had setting "640" inside the running docker container with a "+" marking the extended acls. But the image did not have extended acls installed and could not handle it.

    The weird thing was that, as far as I can see, all other network tools worked (e.g. ping) but only apt could no access the DNS resolver.

    After removing the extended acls from the docker root and setting the usual acls, everything worked inside the running container.

    Similar to the answer of "Promise Prestion", but solved permanently for new containers, too.

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  9. 0

    Specifying a DNS server for docker containers helped me.

    Create a /etc/docker/daemon.json file with this content:

    {
  "dns": ["8.8.8.8", "8.8.4.4"]
}

    and restart the docker service:

    sudo service docker restart

    src: https://docs.docker.com/engine/install/linux-postinstall/#specify-dns-servers-for-docker

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  10. 0

    Similar issue, under debian.
    Root cause was a bad DOCKER-USER rule in iptables chain

    Those rules have been haded

    iptables -I DOCKER-USER -i eno1 -j DROP
iptables -I DOCKER-USER -s 90.62.xxx.xx/32 -i eno1 -j ACCEPT

    so removing temporarily following rule fix the point

    iptables -D DOCKER-USER -i eno1 -j DROP
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  11. 0

    Coming here from some docker cross compiling headache:

    While forking some repo I manually downloaded its root folder containing confd stuff and added it just like the original maintainer did.

    ADD root /

    after this I was not able to apt update anymore.

    I found that the permission of my root named folder was wrong. stat -f "%OLp" root revealed it is 700, but must be 755 to work.

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  12. 0 
    sudo vi /etc/docker/daemon.json

    and check flag of iptables, aslo add DNS if not added

    {...., "iptables":true,"dns": ["8.8.8.8", "8.8.4.4"]}

    then

    sudo service docker restart

    solved me

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  13. 0

    Run this command:

    echo -e "nameserver 8.8.8.8nnameserver 8.8.4.4" |sudo tee -a /etc/resolv.conf

    After that run-

    sudo apt-get update

    This worked for me.

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  14. 0

    I was having the wrong DNS IP address in my /etc/docker/daemon.json. In my case, it was my home router DNS IP address and I was trying from the office network.
    I found out my office DNS and updated with that.

    { 
  "dns": ["192.168.1.1"] 
}
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  15. 0

    I’m using Arch version 6.0.11 and docker version 20.10.21, and having this issues inside docker containers.

    Thanks to @Marco, that was the initial hint to solve this. The problem is related to the use of extended ACLs in the host system.

    The docker root folder has ACLs, you can see this as it has a plus sign at the end of permissions "+":

    $ sudo ls -lh /var/lib/docker
drw-rw-r--+    3 root root 4.0K Nov 24  2021 network

    And what is the problem? Some docker images does not have ACLs installed, so as it was pointed this causes an issue.

    Other network tools like curl resolved DNS properly, but apt or git have problems with DNS resolution.

    TLDR; Where is the fix? Modify ACL to set default rx to others.

    setfacl -R -d -m o::rx /var/lib/docker

    After that, all network tools will be able to perform DNS resolution.

    Credits:

    Marco comment

    Closed git issue in docker

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  16. 0

    The answer from @Mario Olivio Flores suggests using the service command. That is correct and probably works currently on all Linux distributions. However, as most Linux distributions prefer systemd over systemV, it seems better to use just that with the following command:

    sudo systemctl restart docker

    For example, on my Linux distribution the service script located at /usr/sbin/service just wraps systemctl, see this excerpt:

    # When this machine is running systemd, standard service calls are turned into
# systemctl calls.
if [ -n "$is_systemd" ]
then
   UNIT="${SERVICE%.sh}.service"

   case "${ACTION}" in
      restart|status|try-restart)
         exec systemctl $sctl_args ${ACTION} ${UNIT}
      ;;
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  17. 0

    For me, it turned out to be a random WSL 2 issue — running wsl --shutdown and restarting the containers solved it for me.

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