k8s二进制部署 - coredns安装

coredns的资源清单文件
rabc.yaml

apiVersion: v1
kind: ServiceAccount
metadata:
name: coredns
namespace: kube-system
labels:
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
kubernetes.io/bootstrapping: rbac-defaults
addonmanager.kubernetes.io/mode: Reconcile
name: system:coredns
rules:
- apiGroups:
- ""
resources:
- endpoints
- services
- pods
- namespaces
verbs:
- list
- watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
annotations:
rbac.authorization.kubernetes.io/autoupdate: "true"
labels:
kubernetes.io/bootstrapping: rbac-defaults
addonmanager.kubernetes.io/mode: EnsureExists
name: system:coredns
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: system:coredns
subjects:
- kind: ServiceAccount
name: coredns
namespace: kube-system

configmap.yaml

apiVersion: v1
kind: ConfigMap
metadata:
name: coredns
namespace: kube-system
data:
Corefile: |
.:53 {
errors
log
health
ready
kubernetes cluster.local 192.168.0.0/16
forward . 10.4.7.11
cache 30
loop
reload
loadbalance
}

deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
name: coredns
namespace: kube-system
labels:
k8s-app: coredns
kubernetes.io/name: "CoreDNS"
spec:
replicas: 1
selector:
matchLabels:
k8s-app: coredns
template:
metadata:
labels:
k8s-app: coredns
spec:
priorityClassName: system-cluster-critical
serviceAccountName: coredns
containers:
- name: coredns
image: harbor.od.com/public/coredns:v1.6.1
args:
- -conf
- /etc/coredns/Corefile
volumeMounts:
- name: config-volume
mountPath: /etc/coredns
ports:
- containerPort: 53
name: dns
protocol: UDP
- containerPort: 53
name: dns-tcp
protocol: TCP
- containerPort: 9153
name: metrics
protocol: TCP
livenessProbe:
httpGet:
path: /health
port: 8080
scheme: HTTP
initialDelaySeconds: 60
timeoutSeconds: 5
successThreshold: 1
failureThreshold: 5
dnsPolicy: Default
volumes:
- name: config-volume
configMap:
name: coredns
items:
- key: Corefile
path: Corefile

service.yaml

apiVersion: v1
kind: Service
metadata:
name: coredns
namespace: kube-system
labels:
k8s-app: coredns
kubernetes.io/cluster-service: "true"
kubernetes.io/name: "CoreDNS"
spec:
selector:
k8s-app: coredns
clusterIP: 192.168.0.2
ports:
- name: dns
port: 53
protocol: UDP
- name: dns-tcp
port: 53
- name: metrics
port: 9153
protocol: TCP

交付coredns到k8s

[root@hdss7-21 ~]# kubectl apply -f http://k8s-yaml.od.com/coredns/coredns_1.6.1/rbac.yaml
[root@hdss7-21 ~]# kubectl apply -f http://k8s-yaml.od.com/coredns/coredns_1.6.1/configmap.yaml
[root@hdss7-21 ~]# kubectl apply -f http://k8s-yaml.od.com/coredns/coredns_1.6.1/deployment.yaml
[root@hdss7-21 ~]# kubectl apply -f http://k8s-yaml.od.com/coredns/coredns_1.6.1/service.yaml
[root@hdss7-21 ~]# kubectl get all -n kube-system -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
pod/coredns-6b6c4f9648-4vtcl 1/1 Running 0 38s 172.7.21.3 hdss7-21.host.com <none> <none>
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service/coredns ClusterIP 192.168.0.2 <none> 53/UDP,53/TCP,9153/TCP 29s k8s-app=coredns
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
deployment.apps/coredns 1/1 1 1 39s coredns harbor.od.com/public/coredns:v1.6.1 k8s-app=coredns
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
replicaset.apps/coredns-6b6c4f9648 1 1 1 39s coredns harbor.od.com/public/coredns:v1.6.1 k8s-app=coredns,pod-template-hash=6b6c4f9648

测试dns

# 创建service
[root@hdss7-21 ~]# kubectl create deployment nginx-web --image=harbor.od.com/public/nginx:src_1.14.2
[root@hdss7-21 ~]# kubectl expose deployment nginx-web --port=80 --target-port=80
[root@hdss7-21 ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 192.168.0.1 <none> 443/TCP 8d
nginx-web ClusterIP 192.168.164.230 <none> 80/TCP 8s
# 测试DNS，集群外必须使用FQDN(Fully Qualified Domain Name)，全域名
[root@hdss7-21 ~]# dig -t A nginx-web.default.svc.cluster.local @192.168.0.2 +short # 内网解析OK
192.168.164.230
[root@hdss7-21 ~]# dig -t A www.baidu.com @192.168.0.2 +short # 外网解析OK
www.a.shifen.com.
180.101.49.11
180.101.49.12