无头服务上的 DNS 查找不会返回任何 IP 地址

Question

我正在使用minikube和VirtualBox在Kubernetes中运行一个集群。

这是我的无头服务

apiVersion: v1
kind: Service
metadata:
labels:
service: test
name: test-group-ping
spec:
clusterIP: None
ports:
- port: 4444
name: ping
protocol: TCP
targetPort: 4444
selector:
service: test
sessionAffinity: None
type: ClusterIP

这就是我部署吊舱的方式

apiVersion: apps/v1
kind: Deployment
metadata:
name: test
labels:
app: test
spec:
replicas: 3
selector:
matchLabels:
app: test
template:
metadata:
labels:
app: test
spec:
containers:
- name: test
image: image
env:
- name: KC_PROXY
value: "edge"
- name: PROXY_ADDRESS_FORWARDING
value: "true"
ports:
- containerPort: 8080
- containerPort: 4444
- containerPort: 8888
readinessProbe:
httpGet:
path: "/test"
port: 8080
initialDelaySeconds: 600
periodSeconds: 30

我有另一个用于吊舱的负载均衡器

当我使用kubectl get services时，我得到test-group-ping作为无头服务

test-group-ping   ClusterIP      None             <none>          4444/TCP     8h

kubectl describe service test-group-ping
Name:              test-group-ping
Namespace:         default
Labels:            service=test
Annotations:       <none>
Selector:          service=test
Type:              ClusterIP
IP Family Policy:  SingleStack
IP Families:       IPv4
IP:                None
IPs:               None
Port:              ping  4444/TCP
TargetPort:        4444/TCP
Endpoints:         <none>
Session Affinity:  None
Events:            <none>

我需要这个无头服务的DNS查询

我尝试了test-group-ping.default.svc.cluster.local，但当我尝试对此进行DNS查找时，它不会返回pod 的任何IP地址

% dig +search test-group-ping.default.svc.cluster.local

; <<>> DiG 9.10.6 <<>> +search test-group-ping.default.svc.cluster.local
;; global options: +cmd
;; Got answer:
;; WARNING: .local is reserved for Multicast DNS
;; You are currently testing what happens when an mDNS query is leaked to DNS
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 8544
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;test-group-ping.default.svc.cluster.local. IN A
;; AUTHORITY SECTION:
.           10800   IN  SOA a.root-servers.net. nstld.verisign-grs.com. 2022032100 1800 900 604800 86400
;; Query time: 140 msec
;; SERVER: 2600:1702:8c0:e100::1#53(2600:1702:8c0:e100::1)
;; WHEN: Mon Mar 21 10:33:50 CDT 2022
;; MSG SIZE  rcvd: 151
;; Query time: 140 msec
;; SERVER: 2600:1702:8c0:e100::1#53(2600:1702:8c0:e100::1)
;; WHEN: Mon Mar 21 10:33:50 CDT 2022
;; MSG SIZE  rcvd: 151

Answer 1

您的服务选择器service: test与Pod标签app: test不匹配。