K8s coreDNS插件K8s_external在我的K8s集群中似乎不起作用

Question

我在k8s集群中启用了k8s_external，但它似乎不起作用。

核心文件更新如下：

kubernetes cluster.local
k8s_external bcmt01.nokia.com

然后我删除了coredns pod，让更新后的corefile生效。然后我创建一个服务如下：

kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE 
kubernetes ClusterIP 10.254.0.1 443/TCP 7d20h 
ncs-1-dsx-1 LoadBalancer 10.254.203.4 135.111.190.183 22389:30944/TCP,8989:32634/TCP 48m 
ncs-1-dsx-3 LoadBalancer 10.254.203.3 135.111.190.180 22389:30387/TCP,8989:30697/TCP 2d20h
------------------------------------------------------------------------

当我尝试curl ncs-1-dsx-1.default.svc.cluster.local:22389时，它有效，curl 135.111.190.183:22389有效，但curl ncs-1-dsx-1.default.svc.bcmt01.nokia.com:22389无效。我错过了还是错了？你能帮忙吗？

Answer 1

k8s_external插件的工作方式跳过了svc位。请尝试使用ncs-1-dsx-1.default.bcmt01.nokia.com，或者在区域中包含svc.。

Answer 2

我曾经运行以下命令。dig命令似乎成功了，但ping&curl失败，如下：

[root@bcmt-01-control-01 coredns]# kubectl -n kube-system get svc|grep dns
kube-dns                    ClusterIP   10.254.0.10      <none>  53/UDP,53/TCP,9153/TCP   8d

[root@bcmt-01-control-01 coredns]# dig @10.254.0.10 ncs-1-dsx-1.default.bcmt01.nokia.com +short
135.111.190.183

[root@bcmt-01-control-01 coredns]# curl ncs-1-dsx-1.default.bcmt01.nokia.com:22389
curl: (6) Could not resolve host: ncs-1-dsx-1.default.bcmt01.nokia.com; Unknown error

[root@bcmt-01-control-01 coredns]# curl 135.111.190.183:22389
0▒0x▒)
The client sent a request to the Directory Server that could not be properly decoded as an ASN.1 element:  com.unboundid.asn1.ASN1Exception: Unable to decode the provided ASN.1 element ASN1Element(type=47, valueLength=69, valueBytes='54202f20485454502f312e310d0a557365722d4167656e743a206375726c2f372e32392e300d0a486f73743a203133352e3131312e3139302e3138333a32323338390d0a41') as a sequence because the decoded length of an embedded element exceeds the number of bytes remaining..  Data from client: [readBytes=47 45 54 20 2F 20 48 54 54 50 2F 31 2E 31 0D 0A 55 73 65 72 2D 41 67 65 6E 74 3A 20 63 75 72 6C 2F 37 2E 32 39 2E 30 0D 0A 48 6F 73 74 3A 20 31 33 35 2E 31 31 31 2E 31 39 30 2E 31 38 33 3A 32 32 33 38 39 0D 0A 41 unreadBytes=63 63 65 70 74 3A 20 2A 2F 2A 0D 0A 0D 0A]▒1.3.6.1.4.1.1466.20036