Kubernetes1.91（K8s）安装部署过程（七）--coredns安装

为了是集群内的服务能使用dns进行服务解析，集群内需要使用dns服务器，可以按照kube官方dns，即kubedns或者其他的dns，比如coredns，

本例中按照的为coredns，按照简单，编辑文件执行create部署即可，使用现成的镜像安装。

在/etc/kubernetes/yamlfile新增配置文件coredns.yaml,当然这个文件你随意放置，我只是归类而已，安装节点为master节点，node无需安装

1、预先下载corends的镜像

docker pull registry.docker-cn.com/coredns/coredns:0.9.10

2、新增配置文件coredns.yaml配置文件内容：

注意配置文件中红色指定的image在本地仓库一定要存在，按照第一步下载下来接口，且名称要对应上

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
---
apiVersion: v1
kind: ConfigMap
metadata:
name: coredns
namespace: kube-system
labels:
addonmanager.kubernetes.io/mode: EnsureExists
data:
Corefile: |
.:53 {
errors
log stdout
health
kubernetes cluster.local 10.254.0.0/16
prometheus
proxy . /etc/resolv.conf
cache 30
}
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: coredns
namespace: kube-system
labels:
k8s-app: coredns
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
kubernetes.io/name: "CoreDNS"
spec:
replicas: 1
selector:
matchLabels:
k8s-app: coredns
template:
metadata:
labels:
k8s-app: coredns
spec:
serviceAccountName: coredns
tolerations:
- key: node-role.kubernetes.io/master
effect: NoSchedule
- key: "CriticalAddonsOnly"
operator: "Exists"
containers:
- name: coredns
image: registry.docker-cn.com/coredns/coredns:0.9.10
imagePullPolicy: IfNotPresent
resources:
limits:
memory: 170Mi
requests:
cpu: 100m
memory: 70Mi
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
---
apiVersion: v1
kind: Service
metadata:
name: coredns
namespace: kube-system
labels:
k8s-app: coredns
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
kubernetes.io/name: "CoreDNS"
spec:
selector:
k8s-app: coredns
clusterIP: 10.254.0.2
ports:
- name: dns
port: 53
protocol: UDP
- name: dns-tcp
port: 53
protocol: TCP
- name: metrics
port: 9153
protocol: TCP

3、部署coredns

kubectl create -f coredns.yaml

执行完成后开始添加服务及启动，可以通过kubectl cluster-info查看



以及

kubectl get services coredns -n kube-system