<p>k8s: 1.13.1
corends: 1.2.6</p>

<p>I get "can't resolve" time to time trying to resolve service </p>

<pre><code>[root@k8s-kube-master-vm01 ~]# kubectl exec -it  tiller-deploy-dc85f7fbd-vkqjs -n kube-system nslookup kubernetes-dashboard 
nslookup: can't resolve '(null)': Name does not resolve

Name:      kubernetes-dashboard
Address 1: 10.233.43.194
[root@k8s-kube-master-vm01 ~]# kubectl exec -it  tiller-deploy-dc85f7fbd-vkqjs -n kube-system nslookup kubernetes-dashboard 
nslookup: can't resolve '(null)': Name does not resolve

Name:      kubernetes-dashboard
Address 1: 10.233.43.194
[root@k8s-kube-master-vm01 ~]# kubectl exec -it  tiller-deploy-dc85f7fbd-vkqjs -n kube-system nslookup kubernetes-dashboard 
nslookup: can't resolve '(null)': Name does not resolve

nslookup: can't resolve 'kubernetes-dashboard': Try again
command terminated with exit code 1
</code></pre>

<p>Coredns logs:</p>

<pre><code>[root@k8s-kube-master-vm01 ~]# for p in $(kubectl get pods --namespace=kube-system -l k8s-app=coredns -o name); do kubectl logs --namespace=kube-system $p; done  | grep kubernetes-dashboard
2019-06-18T12:05:22.549Z [INFO] 10.233.124.35:41451 - 32323 "AAAA IN kubernetes-dashboard.kube-system.svc.cluster.local. udp 68 false 512" NOERROR qr,aa,rd,ra 161 0.000192773s
2019-06-18T12:05:22.55Z [INFO] 10.233.124.35:41451 - 32054 "A IN kubernetes-dashboard.kube-system.svc.cluster.local. udp 68 false 512" NOERROR qr,aa,rd,ra 134 0.000112697s
2019-06-18T12:05:25.053Z [INFO] 10.233.124.35:41451 - 32323 "AAAA IN kubernetes-dashboard.kube-system.svc.cluster.local. udp 68 false 512" NOERROR qr,rd,ra 161 0.000115262s
2019-06-18T12:05:25.053Z [INFO] 10.233.124.35:41451 - 32054 "A IN kubernetes-dashboard.kube-system.svc.cluster.local. udp 68 false 512" NOERROR qr,rd,ra 134 0.000037126s
2019-06-18T12:05:10.187Z [INFO] 10.233.124.35:50002 - 59429 "AAAA IN kubernetes-dashboard.kube-system.svc.cluster.local. udp 68 false 512" NOERROR qr,aa,rd,ra 161 0.000160883s
2019-06-18T12:05:10.187Z [INFO] 10.233.124.35:50002 - 59123 "A IN kubernetes-dashboard.kube-system.svc.cluster.local. udp 68 false 512" NOERROR qr,aa,rd,ra 134 0.00006191s
2019-06-18T12:05:16.493Z [INFO] 10.233.124.35:40094 - 37873 "AAAA IN kubernetes-dashboard.kube-system.svc.cluster.local. udp 68 false 512" NOERROR qr,rd,ra 161 0.000113602s
2019-06-18T12:05:16.493Z [INFO] 10.233.124.35:40094 - 37550 "A IN kubernetes-dashboard.kube-system.svc.cluster.local. udp 68 false 512" NOERROR qr,aa,rd,ra 134 0.000154653s
</code></pre>

<p>External addresses are not resolved at all:</p>

<pre><code>[root@k8s-kube-master-vm01 ~]# for p in $(kubectl get pods --namespace=kube-system -l k8s-app=coredns -o name); do kubectl logs --namespace=kube-system $p; done  | grep google.com
2019-06-18T10:18:31.888Z [INFO] 10.233.124.35:45081 - 28149 "AAAA IN google.com.svc.cluster.local. udp 46 false 512" NXDOMAIN qr,aa,rd,ra 139 0.000211934s
2019-06-18T10:18:31.888Z [INFO] 10.233.124.35:45081 - 27872 "A IN google.com.svc.cluster.local. udp 46 false 512" NXDOMAIN qr,aa,rd,ra 139 0.000136701s
2019-06-18T10:18:34.391Z [INFO] 10.233.124.35:45081 - 28149 "AAAA IN google.com.svc.cluster.local. udp 46 false 512" NXDOMAIN qr,rd,ra 139 0.000136248s
2019-06-18T10:18:34.391Z [INFO] 10.233.124.35:45081 - 27872 "A IN google.com.svc.cluster.local. udp 46 false 512" NXDOMAIN qr,rd,ra 139 0.000035216s
2019-06-18T10:20:23.899Z [INFO] 10.233.124.35:57585 - 35314 "AAAA IN google.com.svc.cluster.local. udp 46 false 512" NXDOMAIN qr,aa,rd,ra 139 0.000202737s
2019-06-18T10:20:23.899Z [INFO] 10.233.124.35:57585 - 35055 "A IN google.com.svc.cluster.local. udp 46 false 512" NXDOMAIN qr,aa,rd,ra 139 0.000252218s
2019-06-18T10:20:26.4Z [INFO] 10.233.124.35:57585 - 35314 "AAAA IN google.com.svc.cluster.local. udp 46 false 512" NXDOMAIN qr,rd,ra 139 0.000131456s
2019-06-18T10:20:26.4Z [INFO] 10.233.124.35:57585 - 35055 "A IN google.com.svc.cluster.local. udp 46 false 512" NXDOMAIN qr,rd,ra 139 0.000062335s
2019-06-18T12:11:18.188Z [INFO] 10.233.124.35:50407 - 11706 "AAAA IN google.com.kube-system.svc.cluster.local. udp 58 false 512" NXDOMAIN qr,aa,rd,ra 151 0.000202781s
2019-06-18T12:11:18.188Z [INFO] 10.233.124.35:50407 - 11325 "A IN google.com.kube-system.svc.cluster.local. udp 58 false 512" NXDOMAIN qr,aa,rd,ra 151 0.00015313s
2019-06-18T12:11:20.691Z [INFO] 10.233.124.35:50407 - 11706 "AAAA IN google.com.kube-system.svc.cluster.local. udp 58 false 512" NXDOMAIN qr,rd,ra 151 0.000148718s
2019-06-18T12:11:20.691Z [INFO] 10.233.124.35:50407 - 11325 "A IN google.com.kube-system.svc.cluster.local. udp 58 false 512" NXDOMAIN qr,rd,ra 151 0.000124545s
2019-06-18T12:11:24.528Z [INFO] 10.233.124.35:54579 - 11413 "AAAA IN google.com.kube-system.svc.cluster.local. udp 58 false 512" NXDOMAIN qr,rd,ra 151 0.000074136s
2019-06-18T12:11:24.528Z [INFO] 10.233.124.35:54579 - 11083 "A IN google.com.kube-system.svc.cluster.local. udp 58 false 512" NXDOMAIN qr,rd,ra 151 0.000033644s
2019-06-18T12:11:27.03Z [INFO] 10.233.124.35:54579 - 11413 "AAAA IN google.com.kube-system.svc.cluster.local. udp 58 false 512" NXDOMAIN qr,rd,ra 151 0.000136221s
2019-06-18T12:11:27.03Z [INFO] 10.233.124.35:54579 - 11083 "A IN google.com.kube-system.svc.cluster.local. udp 58 false 512" NXDOMAIN qr,rd,ra 151 0.000190085s
2019-06-18T10:18:31.894Z [INFO] 10.233.124.35:49521 - 63928 "AAAA IN google.com.kube-system.svc.cluster.local. udp 58 false 512" NXDOMAIN qr,aa,rd,ra 151 0.000237032s
2019-06-18T10:18:31.895Z [INFO] 10.233.124.35:49521 - 63636 "A IN google.com.kube-system.svc.cluster.local. udp 58 false 512" NXDOMAIN qr,aa,rd,ra 151 0.000177646s
2019-06-18T10:20:23.905Z [INFO] 10.233.124.35:41078 - 52148 "AAAA IN google.com.kube-system.svc.cluster.local. udp 58 false 512" NXDOMAIN qr,aa,rd,ra 151 0.000218841s
2019-06-18T10:20:23.906Z [INFO] 10.233.124.35:41078 - 51789 "A IN google.com.kube-system.svc.cluster.local. udp 58 false 512" NXDOMAIN qr,aa,rd,ra 151 0.000090002s
</code></pre>

<p>I tried to view /etc/resolv.conf but there are no utilities in the coredns pod:</p>

<pre><code>[root@k8s-kube-master-vm01 ~]# kubectl -n kube-system exec coredns-6fd7dbf94c-czjxj  -it sh
OCI runtime exec failed: exec failed: container_linux.go:348: starting container process caused "exec: \"sh\": executable file not found in $PATH": unknown
command terminated with exit code 126
[root@k8s-kube-master-vm01 ~]# kubectl -n kube-system exec coredns-6fd7dbf94c-czjxj  -it cat /etc/hosts
OCI runtime exec failed: exec failed: container_linux.go:348: starting container process caused "exec: \"cat\": executable file not found in $PATH": unknown
command terminated with exit code 126
[root@k8s-kube-master-vm01 ~]# kubectl -n kube-system exec coredns-6fd7dbf94c-czjxj  -it /bin/cat /etc/hosts
OCI runtime exec failed: exec failed: container_linux.go:348: starting container process caused "exec: \"/bin/cat\": stat /bin/cat: no such file or directory": unknown
command terminated with exit code 126
</code></pre>

Andrey  Belikov
<p>check that you enter the master IP and hostname in /etc/hosts</p>

<pre><code>nano /etc/hosts
master YOUR_IP
</code></pre>

<p>and if does not help you try</p>

<pre><code># systemctl stop kubelet
# systemctl stop docker
# iptables --flush
# iptables -tnat --flush
# systemctl start kubelet
# systemctl start docker
</code></pre>
