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network does not works on a bash shell inside the new pod

I am learning kubernetes on LFS258 course and there is example when need to run apt-get update from shell inside te new pod
[email protected]:~$ kubectl exec -it thirdpage-5cf8d67664-zcmfh -- /bin/bash
[email protected]:/# apt-get update

but when runnig command apt-get update it cannot conect to server

Err:1 http://security.debian.org/debian-security stretch/updates InRelease
Temporary failure resolving 'security.debian.org'
Err:2 http://deb.debian.org/debian stretch InRelease
Temporary failure resolving 'deb.debian.org'
Err:3 http://deb.debian.org/debian stretch-updates InRelease
Temporary failure resolving 'deb.debian.org'
Reading package lists... Done

Best Answers


  • serewiczserewicz Posts: 467


    This looks to be a DNS issue. Each of the attempts to update APT show "failure resolving" as the issue. From the same container can you ping an exterior IP address or name? Please try to ping and some site like linux.com. If these also fail it indicates that the issue is with DNS instead of the container.
    To troubleshoot the DNS issue, are you using an online provider or using VirtualBox? From where you are running kubectl, do you find any issues with access to the outside world? Do you have any firewalls in place which could prevent access from the container to the outside world?


  • Thank for answer!
    Yes I have nstalled ubuntu 16 on virtualbox
    firewall is disabled
    network is in bridge mode so ip addres is in same type as physicalcomputer
    when I am runnig ping it seems that there is not ping installed in pod's environment

    [email protected]:~$ kubectl exec -it thirdpage-7c9b56bfdd-4pmhr -- /bin/bash

    [email protected]:/# ping
    bash: ping: command not found

  • cat command works and gets:

    [email protected]:/# cat /etc/resolv.conf
    search default.svc.cluster.local svc.cluster.local cluster.local
    options ndots:5

  • kakhavkkakhavk Posts: 5
    edited November 2018

    Oh yes I fixed it
    Thanks for helping, I added with command "echo nameserver > /etc/resolv.conf"

  • serewiczserewicz Posts: 467

    On your system which node has as an IP? If it is one of your instances, what does that instance show for /etc/resolv.conf?

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