(1). 获取kube-dns.yml文件
https://github.com/kubernetes/kubernetes/tree/release-1.9/cluster/addons/dns
建议提前拉取镜像
apiVersion: v1
kind: Service
metadata:
name: kube-dns
namespace: kube-system
labels:
k8s-app: kube-dns
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
kubernetes.io/name: "KubeDNS"
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
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: kube-dns
namespace: kube-system
labels:
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
---
apiVersion: v1
kind: ConfigMap
metadata:
name: kube-dns
namespace: kube-system
labels:
addonmanager.kubernetes.io/mode: EnsureExists
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: kube-dns
namespace: kube-system
labels:
k8s-app: kube-dns
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
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:
rollingUpdate:
maxSurge: 10%
maxUnavailable: 0
selector:
matchLabels:
k8s-app: kube-dns
template:
metadata:
labels:
k8s-app: kube-dns
annotations:
scheduler.alpha.kubernetes.io/critical-pod: ''
spec:
tolerations:
- key: "CriticalAddonsOnly"
operator: "Exists"
volumes:
- name: kube-dns-config
configMap:
name: kube-dns
optional: true
containers:
- name: kubedns
image: sapcc/k8s-dns-kube-dns-amd64:1.14.10
resources:
# TODO: Set memory limits when we've profiled the container for large
# clusters, then set request = limit to keep this container in
# guaranteed class. Currently, this container falls into the
# "burstable" category so the kubelet doesn't backoff from restarting it.
limits:
memory: 170Mi
requests:
cpu: 100m
memory: 70Mi
livenessProbe:
httpGet:
path: /healthcheck/kubedns
port: 10054
scheme: HTTP
initialDelaySeconds: 60
timeoutSeconds: 5
successThreshold: 1
failureThreshold: 5
readinessProbe:
httpGet:
path: /readiness
port: 8081
scheme: HTTP
# we poll on pod startup for the Kubernetes master service and
# only setup the /readiness HTTP server once that's available.
initialDelaySeconds: 3
timeoutSeconds: 5
args:
- --domain=cluster.local.
- --dns-port=10053
- --config-dir=/kube-dns-config
- --v=2
env:
- name: PROMETHEUS_PORT
value: "10055"
ports:
- containerPort: 10053
name: dns-local
protocol: UDP
- containerPort: 10053
name: dns-tcp-local
protocol: TCP
- containerPort: 10055
name: metrics
protocol: TCP
volumeMounts:
- name: kube-dns-config
mountPath: /kube-dns-config
- name: dnsmasq
image: sapcc/k8s-dns-dnsmasq-nanny-amd64:1.14.10
livenessProbe:
httpGet:
path: /healthcheck/dnsmasq
port: 10054
scheme: HTTP
initialDelaySeconds: 60
timeoutSeconds: 5
successThreshold: 1
failureThreshold: 5
args:
- -v=2
- -logtostderr
- -configDir=/etc/k8s/dns/dnsmasq-nanny
- -restartDnsmasq=true
- --
- -k
- --cache-size=1000
- --no-negcache
- --log-facility=-
- --server=/cluster.local/127.0.0.1#10053
- --server=/in-addr.arpa/127.0.0.1#10053
- --server=/ip6.arpa/127.0.0.1#10053
ports:
- containerPort: 53
name: dns
protocol: UDP
- containerPort: 53
name: dns-tcp
protocol: TCP
# see: https://github.com/kubernetes/kubernetes/issues/29055 for details
resources:
requests:
cpu: 150m
memory: 20Mi
volumeMounts:
- name: kube-dns-config
mountPath: /etc/k8s/dns/dnsmasq-nanny
- name: sidecar
image: sapcc/k8s-dns-sidecar-amd64:1.14.10
livenessProbe:
httpGet:
path: /metrics
port: 10054
scheme: HTTP
initialDelaySeconds: 60
timeoutSeconds: 5
successThreshold: 1
failureThreshold: 5
args:
- --v=2
- --logtostderr
- --probe=kubedns,127.0.0.1:10053,kubernetes.default.svc.cluster.local,5,SRV
- --probe=dnsmasq,127.0.0.1:53,kubernetes.default.svc.cluster.local,5,SRV
ports:
- containerPort: 10054
name: metrics
protocol: TCP
resources:
requests:
memory: 20Mi
cpu: 10m
dnsPolicy: Default # Don't use cluster DNS.
serviceAccountName: kube-dns
(2). 部署kube-dns
[root@master ~]# kubectl apply -f kube-dns.yml
(3). 创建Deploy(busybox.yml)
apiVersion: apps/v1
kind: Deployment
metadata:
name: busybox-deployment
spec:
replicas: 1
selector:
matchLabels:
app: busybox
template:
metadata:
labels:
app: busybox
spec:
containers:
- name: busybox
image: busybox
command: ["/bin/sh","-ce","tail -f /dev/null"]
(4). 部署busybox
[root@master ~]# kubectl apply -f busybox.yml
(5). 验证
# 1. 查看:pod/service
[root@master ~]# kubectl get pods,svc -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
pod/busybox-deployment-74c549f577-rwl2w 1/1 Running 0 39m 172.20.28.2 10.211.55.102 <none> <none>
pod/nginx-6799fc88d8-mx7t6 1/1 Running 0 5m54s 172.20.97.2 10.211.55.101 <none> <none>
pod/nginx-6799fc88d8-n4t5j 1/1 Running 0 25m 172.20.28.4 10.211.55.102 <none> <none>
pod/nginx-6799fc88d8-shrn8 1/1 Running 0 5m54s 172.20.97.3 10.211.55.101 <none> <none>
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
service/kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 21h <none>
service/nginx NodePort 10.0.0.142 <none> 80:36826/TCP 25m app=nginx
# 2. 进入(busybox-deployment-74c549f577-rwl2w)容器.
# 测试:ping nginx
[root@master ~]# kubectl exec -it busybox-deployment-74c549f577-rwl2w -- sh
# ********************************************************
# 尝试ping nginx域名
# 只能解析service(name),居然不能解析pod(name),意味着,在Pod内部要使用内部域名,就必须得要用上:Service组件.
# ********************************************************
/ # ping nginx
PING nginx (10.0.0.142): 56 data bytes
64 bytes from 10.0.0.142: seq=0 ttl=64 time=0.052 ms
# 查询路由信息
/ # nslookup nginx
Server: 10.0.0.2
Address: 10.0.0.2:53
Non-authoritative answer:
# nginx对应的域名信息
Name: nginx.default.svc.cluster.local
Address: 10.0.0.142
