coredns crashloopbackoff in kubernetes

Question

I have setup kubernetes in ubuntu 16.04. I am using kube version 1.13.1 and using weave for networking. I have initialized the cluster usi

Answer 1

I had the same problem in ubuntu 16.04. My /etc/resolv.conf pointed to loopback address too. I first tried as S Andrew to change the resolv.conf file manually but although without any luck.

In my case, I have resolved this issue disabling dnsmasq. In /etc/NetworkManager/NetworkManager.conf, comment on the following line in the [main] section:

[main]
#dns=dnsmasq

Dnsmasq makes it simple to specify the nameserver to use for a given domain but sets automatically a loopback address and this makes coredns to crash.

After this the /etc/resolv.conf file pointed to my DNS Servers supplied by my ISP.

Answer 2

I have resolved this issue. In my case I had below contents of /etc/resolv.conf

nameserver     127.0.1.1

I first used the below command to get the correct IP as the device was in client's network.

nmcli device show <interfacename> | grep IP4.DNS

After this I updated the file /etc/resolvconf/resolv.conf.d/head with below contents

nameserver    192.168.66.21

and then run the below command to regenerate the resolv.conf

sudo resolvconf -u

After this I had below contents in /etc/resolv.conf:

nameserver    192.168.66.21
nameserver    127.0.1.1

I then deleted the coredns pods and everything worked fine. Thanks.