coredns.yaml文件如下所示
# __MACHINE_GENERATED_WARNING__
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
- apiGroups:
- ""
resources:
- nodes
verbs:
- get
---
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
---
apiVersion: v1
kind: ConfigMap
metadata:
name: coredns
namespace: kube-system
labels:
addonmanager.kubernetes.io/mode: EnsureExists
data:
Corefile: |
.:53 {
errors
health
kubernetes cluster.local in-addr.arpa ip6.arpa {
pods insecure
upstream
fallthrough in-addr.arpa ip6.arpa
ttl 30
}
prometheus :9153
forward . /etc/resolv.conf
cache 30
loop
reload
loadbalance
}
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: coredns
namespace: kube-system
labels:
k8s-app: kube-dns
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
kubernetes.io/name: "CoreDNS"
spec:
# replicas: not specified here:
# 1. In order to make Addon Manager do not reconcile this replicas parameter.
# 2. Default is 1.
# 3. Will be tuned in real time if DNS horizontal auto-scaling is turned on.
strategy:
type: RollingUpdate
rollingUpdate:
maxUnavailable: 1
selector:
matchLabels:
k8s-app: kube-dns
template:
metadata:
labels:
k8s-app: kube-dns
annotations:
seccomp.security.alpha.kubernetes.io/pod: 'docker/default'
spec:
priorityClassName: system-cluster-critical
serviceAccountName: coredns
tolerations:
- key: "CriticalAddonsOnly"
operator: "Exists"
nodeSelector:
beta.kubernetes.io/os: linux
containers:
- name: coredns
image: k8s.gcr.io/coredns:1.3.1
imagePullPolicy: IfNotPresent
resources:
limits:
memory: 70Mi
requests:
cpu: 100m
memory: 70Mi
args: [ "-conf", "/etc/coredns/Corefile" ]
volumeMounts:
- name: config-volume
mountPath: /etc/coredns
readOnly: true
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
readinessProbe:
httpGet:
path: /health
port: 8080
scheme: HTTP
securityContext:
allowPrivilegeEscalation: false
capabilities:
add:
- NET_BIND_SERVICE
drop:
- all
readOnlyRootFilesystem: true
dnsPolicy: Default
volumes:
- name: config-volume
configMap:
name: coredns
items:
- key: Corefile
path: Corefile
---
apiVersion: v1
kind: Service
metadata:
name: kube-dns
namespace: kube-system
annotations:
prometheus.io/port: "9153"
prometheus.io/scrape: "true"
labels:
k8s-app: kube-dns
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
kubernetes.io/name: "CoreDNS"
spec:
selector:
k8s-app: kube-dns
clusterIP: 10.0.0.2
ports:
- name: dns
port: 53
protocol: UDP
- name: dns-tcp
port: 53
protocol: TCP
- name: metrics
port: 9153
protocol: TCP
修改以上yaml文件中红色部分修改成自己对于的信息
kubectl apply -f coredns.yaml
执行apply 生成pod（需要替换镜像，不然会拉取失败）
[root@k8s-master yaml]# kubectl get all -n kube-system | grep coredns
pod/coredns-867ccfd476-9ghff 1/1 Running 13 42h
pod/coredns-867ccfd476-p5md4 1/1 Running 15 42h
deployment.apps/coredns 2/2 2 2 44h
replicaset.apps/coredns-867ccfd476 2 2 2 44h
[root@k8s-master yaml]#
创建测试的pod
[root@k8s-master test]# cat my-apache.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: my-apache
spec:
replicas: 2
template:
metadata:
labels:
run: my-apache
spec:
containers:
- name: my-apache
image: httpd:2.4
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: my-apache
labels:
run: my-apache
spec:
type: NodePort
ports:
- port: 80
targetPort: 80
nodePort: 30002
selector:
run: my-apache
生成pod
[root@k8s-master test]# kubectl apply -f my-apache.yaml
查看pod运行状态
[root@k8s-master test]# kubectl get pod
NAME READY STATUS RESTARTS AGE
my-apache-75f574f468-8psfw 1/1 Running 1 24h
my-apache-75f574f468-msrrn 1/1 Running 0 24h
[root@k8s-master test]#
已经全部运行
[root@k8s-master test]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 2d
my-apache NodePort 10.0.0.71 <none> 80:30002/TCP 24h
[root@k8s-master test]# curl 10.0.0.71
<html><body><h1>It works!</h1></body></html>
[root@k8s-master test]#
由此可见dns服务是可用的
