k8s系列 - coredns增加解析

k8s中coredns可以为全集群提供dns解析功能， 所以如果我们要手动增加dns解析， 只需在coredns中增加dns解析对即可

1. 编辑coredns
kubectl edit cm/coredns -n kube-system

2. 内容如下

# Please edit the object below. Lines beginning with a '#' will be ignored,
# and an empty file will abort the edit. If an error occurs while saving this file will be
# reopened with the relevant failures.
#
apiVersion: v1
data:
  Corefile: |
    .:53 {
        errors
        health {
           lameduck 5s
        }
        ready
        kubernetes cluster.local in-addr.arpa ip6.arpa {
           pods insecure
           fallthrough in-addr.arpa ip6.arpa
           ttl 30
        }
        prometheus :9153
        forward . /etc/resolv.conf {
           max_concurrent 1000
        }
        cache 30
        loop
        reload
        loadbalance
    }
kind: ConfigMap
metadata:
  creationTimestamp: "2021-07-15T12:08:07Z"
  name: coredns
  namespace: kube-system
  resourceVersion: "245"
  uid: 0b992b6b-9498-4d83-8f80-073ef0861cf3

3. 增加 dns解析

hosts {
            192.168.100.100  <dns_path>
            fallthrough
        }
# 注意 hosts 增加与 prometheus 对其