1. The basic cluster deployment pod of inquiry k8s
The following diagram, we can see the container coredns and dnsutils are deployed successfully, but because of name resolution problems, leading to coredns and dnsutils container constantly reboot (check heath reasons, can not request succeeds, it is kubelet restart the pod)
Command is as follows:
root >> kubectl get all --all-namespaces -o wide
root >> kubectl describe pod coredns-57bbd778b9-kxl7b -n kube-system
root >> kubectl logs coredns-57bbd778b9-kxl7b -n kube-system
2. Modify the VM file before DNS resolution,
As shown below: cat /etc/resolv.conf is in 192.168.3.1 DNS name card set I VM physical machines, this is a virtual incorrect DNS address, actually I IP router.
docker exec -it fda365569efa / bin / bash, showing access to the interior dnsutils-ds-55fpd k8s container.
10.3.0.2, this is ClusterIP I k8s defined in the cluster and create CoreDNS container, if the deployment is successful, domain name service or access outside the network, you can do it through address resolution.
Question: below, inside the container, can not resolve the external address and the internal address cluster.local www.baidu.com normal. Here is a description of the physical machine VM nameserver configuration error.
3. Modify the VM after DNS resolution files,
NIC # modify the configuration file on the VM eno01 machine, as shown alternatively correct DNS address.
# Here we use Google's DNS domain name and local address 8.8.8.8 K8S cluster CoreDNS of CluterIP address 10.3.0.2.
root >> vi /etc/sysconfig/network-scripts/ifcfg-eno01
# Then remember to save, and then restart the VM machine, we re-examine CoreDNS resolution is normal, as follows:
root >> cat /etc/sysconfig/network-scripts/ifcfg-eno01
root >> cat /etc/resolv.conf
root >> ping -c 1 www.baidu.com
root >> ping -c 1 10.3.0.2
root >> ping -c 1 kubernetes
root >> nslookup www.baidu.com
root >> nslookup kubernetes
root >> nslookup kube-dns.kube-system.svc
root >> nslookup kube-dns.kube-system.svc.cluster.local
root >> nslookup cluster.local
#### docker dns resolve internal inspection
root >> docker ps | grep dns
dnsutils root >>