一、kube-dns
目前常用的dns组件有kube-dns和coredns两个，用于解析k8s集群中service name所对应得到IP地址。
DNS全称：service名.namespace名.svc.zzhz.local
#创建pod测试查看DNS地址和名称(域名无法ping通，是DNS没有设置)
kubectl run net-test1 --image=alpine --replicas=4 sleep 360000
[root@localhost7G ~]# docker exec -it k8s_net-test1_net-test1-5fcc69db59-v7zqg_ sh
/ # cat /etc/resolv.conf
nameserver 10.10.0.2
search default.svc.zzhz.local. svc.zzhz.local. zzhz.local. localdomain
options ndots:5
/ # ping 223.6.6.6
PING 223.6.6.6 (223.6.6.6): 56 data bytes
64 bytes from 223.6.6.6: seq=0 ttl=127 time=5.307 ms
64 bytes from 223.6.6.6: seq=1 ttl=127 time=7.684 ms
64 bytes from 223.6.6.6: seq=2 ttl=127 time=6.144 ms
/ # ping www.qq.com
ping: bad address 'www.qq.com'
kube-dns组件名称
kube-dns： 提供service name域名的解析
dns-dnsmasq：提供DNS缓存，降低kubedns负载，提高性能
dns-sidecar：定期检查kubedns和dnsmasq的健康状态
#镜像制作
docker load -i k8s-dns-dnsmasq-nanny-amd64_1.14.13.tar.gz
docker load -i k8s-dns-kube-dns-amd64_1.14.13.tar.gz
docker load -i k8s-dns-sidecar-amd64_1.14.13.tar.gz
docker tag 333fb0833870 harbor.zzhz.com/baseimage/k8s-dns-sidecar-amd64:1.14.13
docker tag 82f954458b31 harbor.zzhz.com/baseimage/k8s-dns-kube-dns-amd64:1.14.13
docker tag 7b15476a7228 harbor.zzhz.com/baseimage/k8s-dns-dnsmasq-nanny-amd64:1.14.13
docker push harbor.zzhz.com/baseimage/k8s-dns-sidecar-amd64:1.14.13
docker push harbor.zzhz.com/baseimage/k8s-dns-dnsmasq-nanny-amd64:1.14.13
docker push harbor.zzhz.com/baseimage/k8s-dns-kube-dns-amd64:1.14.13
#查看配置文件
[root@localhost7C k8s]# cat kube-dns.yaml
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: 10.10.0.2 # 测试创建一个容器，查看DNS文件定义的，
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: ''
seccomp.security.alpha.kubernetes.io/pod: 'docker/default'
spec:
priorityClassName: system-cluster-critical
securityContext:
supplementalGroups: [ 65534 ]
fsGroup: 65534
tolerations:
- key: "CriticalAddonsOnly"
operator: "Exists"
volumes:
- name: kube-dns-config
configMap:
name: kube-dns
optional: true
containers:
- name: kubedns
image: harbor.zzhz.com/baseimage/k8s-dns-kube-dns-amd64:1.14.13 #
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: 512Mi #硬件资源设置
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=zzhz.local. #二进制安装里的域名名称
- --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: harbor.zzhz.com/baseimages/k8s-dns-dnsmasq-nanny-amd64:1.14.13 #
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
- --dns-loop-detect
- --log-facility=-
- --server=/zzhz.local/127.0.0.1#10053 #zzhz.local 的域交给127.0.0.1 的100053端口去解析
#- --server=/zjol.com/6.6.6.6#10053 #zjol.com 的域交给6.6.6.6 的100053端口去解析
- --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: harbor.zzhz.com/baseimages/k8s-dns-sidecar-amd64:1.14.13 #
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.zzhz.local,5,SRV #
- --probe=dnsmasq,127.0.0.1:53,kubernetes.default.svc.zzhz.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
#部署
kubectl apply -f kube-dns.yaml
#测试
[root@localhost7G ~]# docker exec -it k8s_net-test1_net-test1-5fcc69db59-v7zqg_ sh
/ # ping www.qq.com
PING www.qq.com (101.91.42.232): 56 data bytes
64 bytes from 101.91.42.232: seq=0 ttl=127 time=12.003 ms
64 bytes from 101.91.42.232: seq=1 ttl=127 time=12.686 ms
64 bytes from 101.91.42.232: seq=2 ttl=127 time=12.697 ms
---------------------------------------------------------------
二、coredns
apiVersion: v1
kind: ServiceAccount
metadata:
name: coredns
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
kubernetes.io/bootstrapping: rbac-defaults
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
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
data: #设置名称和Forward
Corefile: |
.:53 {
errors
health {
lameduck 5s
}
ready
#DNS名称
kubernetes zzhz.local in-addr.arpa ip6.arpa {
fallthrough in-addr.arpa ip6.arpa
}
prometheus :9153
#解析不了的转发
forward . 223.6.6.6
#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/name: "CoreDNS"
spec:
# replicas: not specified here:
# 1. Default is 1.
# 2. 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
spec:
priorityClassName: system-cluster-critical
serviceAccountName: coredns
tolerations:
- key: "CriticalAddonsOnly"
operator: "Exists"
nodeSelector:
kubernetes.io/os: linux
affinity:
podAntiAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
- labelSelector:
matchExpressions:
- key: k8s-app
operator: In
values: ["kube-dns"]
topologyKey: kubernetes.io/hostname
containers:
- name: coredns
image: coredns/coredns:1.6.7 #镜像地址
imagePullPolicy: IfNotPresent
resources:
limits:
memory: 700Mi #资源限制
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
securityContext:
allowPrivilegeEscalation: false
capabilities:
add:
- NET_BIND_SERVICE
drop:
- all
readOnlyRootFilesystem: true
livenessProbe:
httpGet:
path: /health
port: 8080
scheme: HTTP
initialDelaySeconds: 60
timeoutSeconds: 5
successThreshold: 1
failureThreshold: 5
readinessProbe:
httpGet:
path: /ready
port: 8181
scheme: HTTP
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"
kubernetes.io/name: "CoreDNS"
spec:
selector:
k8s-app: kube-dns
clusterIP: 10.10.0.2 #DNS IP
ports:
- name: dns
port: 53
protocol: UDP
- name: dns-tcp
port: 53
protocol: TCP
- name: metrics
port: 9153
protocol: TCP
标签：k8s,dns,kubernetes,DNS,io,kube,name From： https://www.cnblogs.com/Yuanbangchen/p/17219145.html