更新kubedns文档

pull/275/head v184-r1
jmgao 2017-12-08 17:43:51 +08:00
parent 2d26c016ba
commit 8251c7335c
5 changed files with 255 additions and 6 deletions

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@ -1,7 +1,7 @@
# 在deploy节点生成CA相关证书以供整个集群使用
- hosts: deploy
roles:
- ca
- deploy
# 集群节点的公共配置任务
- hosts:

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@ -162,7 +162,7 @@ spec:
### 验证calico网络
执行calico安装 `ansible-playbook 05.calico.yml` 成功后可以验证如下:需要等待一会儿
执行calico安装 `ansible-playbook 05.calico.yml` 成功后可以验证如下:(需要等待calico/node:v2.6.2 镜像下载完成有时候即便上一步已经配置了docker国内加速还是可能比较慢建议确认以下容器运行起来以后再执行后续步骤)
``` bash
docker ps

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@ -6,7 +6,58 @@ kubedns 是 k8s 集群首先需要部署的,集群中的其他 pods 使用它
### 安装
kubectl create -f /etc/ansible/manifests/kubedns/[kubedns.yaml](../../manifests/kubedns/kubedns.yaml)
**kubectl create -f /etc/ansible/manifests/kubedns/[kubedns.yaml](../../manifests/kubedns/kubedns.yaml)**
+ 注意deploy中使用的 serviceAccount `kube-dns`,该预定义的 ClusterRoleBinding system:kube-dns 将 kube-system 命名空间的 kube-dns ServiceAccount 与 system:kube-dns ClusterRole 绑定, 因此POD 具有访问 kube-apiserver DNS 相关 API 的权限;
+ 集群 pod默认继承 node的dns 解析,修改 kubelet服务启动参数 --resolv-conf="",可以更改这个特性,详见 kubelet 启动参数
### 验证 kubedns
新建一个测试nginx服务
`kubectl run nginx --image=nginx --expose --port=80`
确认nginx服务
``` bash
kubectl get pod|grep nginx
nginx-7cbc4b4d9c-fl46v 1/1 Running 0 1m
kubectl get svc|grep nginx
nginx ClusterIP 10.68.33.167 <none> 80/TCP 1m
```
测试pod busybox
``` bash
kubectl run busybox --rm -it --image=busybox /bin/sh
If you don't see a command prompt, try pressing enter.
/ # cat /etc/resolv.conf
nameserver 10.68.0.2
search default.svc.cluster.local. svc.cluster.local. cluster.local.
options ndots:5
# 测试集群内部服务解析
/ # nslookup nginx
Server: 10.68.0.2
Address 1: 10.68.0.2 kube-dns.kube-system.svc.cluster.local
Name: nginx
Address 1: 10.68.33.167 nginx.default.svc.cluster.local
/ # nslookup kubernetes
Server: 10.68.0.2
Address 1: 10.68.0.2 kube-dns.kube-system.svc.cluster.local
Name: kubernetes
Address 1: 10.68.0.1 kubernetes.default.svc.cluster.local
# 测试外部域名的解析默认集成node的dns解析
/ # nslookup www.baidu.com
Server: 10.68.0.2
Address 1: 10.68.0.2 kube-dns.kube-system.svc.cluster.local
Name: www.baidu.com
Address 1: 180.97.33.108
Address 2: 180.97.33.107
/ #
```

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@ -0,0 +1,198 @@
---
apiVersion: v1
kind: ConfigMap
metadata:
name: kube-dns
namespace: kube-system
labels:
addonmanager.kubernetes.io/mode: EnsureExists
---
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: 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: 10.68.0.2
ports:
- name: dns
port: 53
protocol: UDP
- name: dns-tcp
port: 53
protocol: TCP
---
apiVersion: extensions/v1beta1
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: gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.5
image: mirrorgooglecontainers/k8s-dns-kube-dns-amd64:1.14.5
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: gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.5
image: mirrorgooglecontainers/k8s-dns-dnsmasq-nanny-amd64:1.14.5
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
- --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: gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.5
image: mirrorgooglecontainers/k8s-dns-sidecar-amd64:1.14.5
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,A
- --probe=dnsmasq,127.0.0.1:53,kubernetes.default.svc.cluster.local.,5,A
ports:
- containerPort: 10054
name: metrics
protocol: TCP
resources:
requests:
memory: 20Mi
cpu: 10m
dnsPolicy: Default # Don't use cluster DNS.
serviceAccountName: kube-dns

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@ -1,6 +1,6 @@
### 说明
+ 本目录为k8s集群的插件 kube-dns的配置目录,初始时本目录为空
+ 本目录为k8s集群的插件 kube-dns的配置目录
+ 因kubedns.yaml文件中参数(CLUSTER_DNS_SVC_IP, CLUSTER_DNS_DOMAIN)根据hosts文件设置而定需要使用ansible template模块替换参数后生成
+ 运行 `ansible-playbook 01.prepare.yml`该目录下生成kubedns.yaml 文件
+ kubedns.yaml [模板文件](../../roles/deploy/template/kubedns.yaml.j2)
+ 运行 `ansible-playbook 01.prepare.yml`会重新生成该目录下的kubedns.yaml 文件
+ kubedns.yaml [模板文件](../../roles/deploy/templates/kubedns.yaml.j2)