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Issue on lab 9.3: Working with CoreDNS

andrea.calvario
andrea.calvario Posts: 22
in LFS258 Class Forum

Here again for another issue on the 9.3 lab: my pod cannot resolve addresses.
After a lot of problems, as described in my past discussion, I recreate the entire cluster, so I'm now able to go ahead, but, reached this lab (9.3) I found another problem. The feeling is that the coredns doesn't work correctly, I restart them, but the problem persists.
I provide here some information and configuration, hoping that someone can help me to identify the problem.

Status of the coredns pods

**kubectl get pods --all-namespaces | grep coredns**
kube-system   coredns-6b4b86d8bf-2r222                   1/1     Running   0          12m
kube-system   coredns-6b4b86d8bf-nqj2m                   1/1     Running   0          12m

my /etc/resolve.conf file on the host

nameserver 127.0.0.53
options edns0 trust-ad
search homenet.telecomitalia.it

/etc/resolve.conf file on nettool pod

nameserver 10.96.0.10
search default.svc.cluster.local svc.cluster.local cluster.local homenet.telecomitalia.it
options ndots:5

Output of the apt update command executed in the pod

root@nettool:/# apt update
Err:1 http://security.ubuntu.com/ubuntu focal-security InRelease         
  Temporary failure resolving 'security.ubuntu.com'
Err:2 http://archive.ubuntu.com/ubuntu focal InRelease                   
  Temporary failure resolving 'archive.ubuntu.com'
Err:3 http://archive.ubuntu.com/ubuntu focal-updates InRelease
  Temporary failure resolving 'archive.ubuntu.com'
Err:4 http://archive.ubuntu.com/ubuntu focal-backports InRelease
  Temporary failure resolving 'archive.ubuntu.com'
Reading package lists... Done        
Building dependency tree       
Reading state information... Done
All packages are up to date.
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal/InRelease  Temporary failure resolving 'archive.ubuntu.com'
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal-updates/InRelease  Temporary failure resolving 'archive.ubuntu.com'
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/focal-backports/InRelease  Temporary failure resolving 'archive.ubuntu.com'
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/focal-security/InRelease  Temporary failure resolving 'security.ubuntu.com'
W: Some index files failed to download. They have been ignored, or old ones used instead.

Log from the coredns pods

**kubectl logs coredns-6b4b86d8bf-2r222 --namespace kube-system **
.:53
[INFO] plugin/reload: Running configuration MD5 = db32ca3650231d74073ff4cf814959a7
CoreDNS-1.7.0
linux/amd64, go1.14.4, f59c03d
[ERROR] plugin/errors: 2 2411310349111695803.1156763954485922933. HINFO: read udp 192.168.140.134:50073->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 2411310349111695803.1156763954485922933. HINFO: read udp 192.168.140.134:53444->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 2411310349111695803.1156763954485922933. HINFO: read udp 192.168.140.134:33483->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 2411310349111695803.1156763954485922933. HINFO: read udp 192.168.140.134:60055->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 2411310349111695803.1156763954485922933. HINFO: read udp 192.168.140.134:45734->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 2411310349111695803.1156763954485922933. HINFO: read udp 192.168.140.134:58277->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 2411310349111695803.1156763954485922933. HINFO: read udp 192.168.140.134:48417->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 2411310349111695803.1156763954485922933. HINFO: read udp 192.168.140.134:45403->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 2411310349111695803.1156763954485922933. HINFO: read udp 192.168.140.134:43683->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 2411310349111695803.1156763954485922933. HINFO: read udp 192.168.140.134:52890->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 security.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:40467->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:55114->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:54780->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 security.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:32826->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.140.134:34987->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:57937->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:54716->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.140.134:37758->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:48427->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:39343->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.140.134:55263->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 security.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:51377->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:35208->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 security.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:45064->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 security.ubuntu.com. A: read udp 192.168.140.134:36542->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 security.ubuntu.com. A: read udp 192.168.140.134:59127->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.140.134:52336->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.140.134:55511->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:58522->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.140.134:48809->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 security.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:59664->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:44874->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 security.ubuntu.com. A: read udp 192.168.140.134:50931->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.140.134:34514->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:54530->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:45994->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.140.134:60092->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:39119->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com.homenet.telecomitalia.it. A: read udp 192.168.140.134:59702->192.168.1.1:53: i/o timeout
[ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.140.134:45259->192.168.1.1:53: i/o timeout

Can someone help me to understand where I mistaking?

Thanks in advance!

Andy74

Comments

  • chrispokorni
    chrispokorni Posts: 2,606

    Hi @andrea.calvario,

    The issue you are experiencing at this point seems to be related to how your Internet Service Provider operates. It is trying to locate *.ubuntu.com on homenet.telecomitalia.it domain.

    With a simple google search I was able to find a forum post that should provide you with a solution around the DNS issues with telecomitalia. I hope it helps to fix your host's resolv.conf file:

    https://forum.ubuntu-it.org/viewtopic.php?t=428583

    Regards,
    -Chris

  • paristiz
    paristiz Posts: 12

    Hi,

    I am experiencing the same issue but the logs don't show the same error related with ISP (until I can understand). Is there something I can do?

    These are the logs from both CoreDNS pods:

    ablo@pablo-VirtualBox:~$ kubectl -n kube-system logs coredns-f9fd979d6-2nd2n
    .:53
    [INFO] plugin/reload: Running configuration MD5 = 823e90b886243896bc5fc311d1fe380f
    CoreDNS-1.7.0
    linux/amd64, go1.14.4, f59c03d
    [ERROR] plugin/errors: 2 5854889205053853889.4992786380578661315. HINFO: read udp 192.168.54.36:36158->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 5854889205053853889.4992786380578661315. HINFO: read udp 192.168.54.36:37468->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 5854889205053853889.4992786380578661315. HINFO: read udp 192.168.54.36:33847->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 5854889205053853889.4992786380578661315. HINFO: read udp 192.168.54.36:58102->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 5854889205053853889.4992786380578661315. HINFO: read udp 192.168.54.36:56101->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 5854889205053853889.4992786380578661315. HINFO: read udp 192.168.54.36:35935->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 5854889205053853889.4992786380578661315. HINFO: read udp 192.168.54.36:49304->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 5854889205053853889.4992786380578661315. HINFO: read udp 192.168.54.36:37233->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 5854889205053853889.4992786380578661315. HINFO: read udp 192.168.54.36:58338->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 5854889205053853889.4992786380578661315. HINFO: read udp 192.168.54.36:56906->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 security.ubuntu.com. A: read udp 192.168.54.36:44621->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.54.36:39647->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.54.36:43970->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.54.36:49128->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.54.36:43476->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.54.36:54778->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.54.36:35449->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.54.36:32906->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.54.36:39382->192.168.18.1:53: i/o timeout
    pablo@pablo-VirtualBox:~$ kubectl -n kube-system logs coredns-f9fd979d6-sbmlw
    .:53
    [INFO] plugin/reload: Running configuration MD5 = 823e90b886243896bc5fc311d1fe380f
    CoreDNS-1.7.0
    linux/amd64, go1.14.4, f59c03d
    [ERROR] plugin/errors: 2 7925864582003874829.5346898514191063070. HINFO: read udp 192.168.54.39:49955->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 7925864582003874829.5346898514191063070. HINFO: read udp 192.168.54.39:47710->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 7925864582003874829.5346898514191063070. HINFO: read udp 192.168.54.39:36716->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 7925864582003874829.5346898514191063070. HINFO: read udp 192.168.54.39:60608->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 7925864582003874829.5346898514191063070. HINFO: read udp 192.168.54.39:39340->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 7925864582003874829.5346898514191063070. HINFO: read udp 192.168.54.39:57446->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 7925864582003874829.5346898514191063070. HINFO: read udp 192.168.54.39:42763->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 security.ubuntu.com. A: read udp 192.168.54.39:53249->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.54.39:42660->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.54.39:32993->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 security.ubuntu.com. A: read udp 192.168.54.39:54913->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 security.ubuntu.com. A: read udp 192.168.54.39:35481->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.54.39:59322->192.168.18.1:53: i/o timeout
    [ERROR] plugin/errors: 2 archive.ubuntu.com. A: read udp 192.168.54.39:48382->192.168.18.1:53: i/o timeout

    As you can see I am working with virtual machines, so far, I haven´t had DNS issues.

    Any information will be appreciated

    Pablo A.

  • RonaldHeirbaut
    RonaldHeirbaut Posts: 9

    I had the same issue running on debian 10. I installed the resolvconf package and changed the DNS on the masternode from my local DNS (192.168.1.1) to external DNS (1.1.1.1). And of course a static IP configured on the node. That solved it for me.

  • paristiz
    paristiz Posts: 12

    Hi, thank you for your answers. I had already checked the pods out and they were always running. Finally, I followed the RonaldHeirbaut recommendation and downloaded the resolvconf package on the masternode and after that, my pod was able to download the dig and other tools needed for the practice.

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