kubernetes v1.11 二进制部署篇章目录

• kubernetes v1.11 二进制部署
  • （一）环境介绍
  • （二）Openssl自签TLS证书
  • （三）master组件部署
  • （四）node组件部署

前言

在经过上一篇章Calico集成kubernetes的CNI网络部署全过程、启用CA自签名之后，kubernetes每台node节点的状态已经是ready状态了，那么下一步就是需要解决kubernetes集群中pod的域名解析问题。

 

为什么要解决这个问题呢？

因为kuberntes中的所有pod都是基于service域名解析后，再负载均衡分发到service后端的各个pod服务中，那么如果没有DNS解析，则无法查到各个服务对应的service服务，以下举个例子。

1.首先上传一个基于centos的工具镜像

[root@server81 registry]# docker push 172.16.5.181:5000/networkbox
The push refers to repository [172.16.5.181:5000/networkbox]
6793eb3b0692: Pushed 
4b398ee02e06: Pushed 
b91100adb338: Pushed 
5f70bf18a086: Pushed 
479d1ea9f888: Pushed 
latest: digest: sha256:0159b2282815ecd59809dcca4d74cffd5b75a9ca5deec8a220080c254cc43ff2 size: 1987
[root@server81 registry]# 

2.创建pod以及svc

[root@server81 test_yaml]# vim networkbox.yaml apiVersion: extensions/v1beta1
kind: Deployment
metadata:name: networkboxlabels:app: networkbox
spec:replicas: 10template:metadata:labels:app: networkboxspec:terminationGracePeriodSeconds: 60containers:- name: networkboximage: 172.16.5.181:5000/networkbox
---
apiVersion: v1
kind: Service
metadata:name: networkboxlabels:name: networkbox
spec:ports:- port: 8008selector:name: networkbox
[root@server81 test_yaml]# vim networkbox.yaml 
[root@server81 test_yaml]# 
[root@server81 test_yaml]# kubectl apply -f networkbox.yaml 
deployment.extensions/networkbox configured
service/networkbox unchanged
[root@server81 test_yaml]# 
[root@server81 test_yaml]# kubectl get pod -o wide
NAME                          READY     STATUS        RESTARTS   AGE       IP           NODE
networkbox-85bd85cd54-7hsgp   1/1       Terminating   0          1m        10.1.0.196   172.16.5.181
networkbox-85bd85cd54-7sr5f   1/1       Terminating   0          1m        10.1.0.65    172.16.5.87
networkbox-85bd85cd54-9j8cg   1/1       Running       0          1m        10.1.0.194   172.16.5.181
networkbox-85bd85cd54-btcvz   1/1       Terminating   0          1m        10.1.0.198   172.16.5.181
networkbox-85bd85cd54-btmwm   1/1       Terminating   0          1m        10.1.0.200   172.16.5.181
networkbox-85bd85cd54-dfngz   1/1       Terminating   0          1m        10.1.0.197   172.16.5.181
networkbox-85bd85cd54-gp525   1/1       Terminating   0          1m        10.1.0.66    172.16.5.87
networkbox-85bd85cd54-llrw6   1/1       Running       0          1m        10.1.0.193   172.16.5.181
networkbox-85bd85cd54-psh4r   1/1       Running       0          1m        10.1.0.195   172.16.5.181
networkbox-85bd85cd54-zsg8m   1/1       Terminating   0          1m        10.1.0.199   172.16.5.181
[root@server81 test_yaml]# 
[root@server81 test_yaml]# kubectl get svc
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)    AGE
kubernetes   ClusterIP   10.0.6.1     <none>        443/TCP    1h
networkbox   ClusterIP   10.0.6.138   <none>        8008/TCP   1m
[root@server81 test_yaml]# 

3.进入networkbox的容器内，ping service域名，确认是否返回IP地址

[root@server81 test_yaml]# kubectl get svc
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)    AGE
kubernetes   ClusterIP   10.0.6.1     <none>        443/TCP    1h
networkbox   ClusterIP   10.0.6.138   <none>        8008/TCP   1m
[root@server81 test_yaml]# 
[root@server81 test_yaml]# kubectl exec -it networkbox-85bd85cd54-9j8cg bash
[root@networkbox-85bd85cd54-9j8cg /]# 
[root@networkbox-85bd85cd54-9j8cg /]# ping networkbox
ping: unknown host networkbox
[root@networkbox-85bd85cd54-9j8cg /]# 
[root@networkbox-85bd85cd54-9j8cg /]# ping kubernetes
ping: unknown host kubernetes
[root@networkbox-85bd85cd54-9j8cg /]# 

可以看出在容器内由于没有kubernetes的DNS服务解析，容器是找不到service的IP地址，那么也就找不到后面的服务了，所以CoreDNS的解析服务是必须要安装好的。

CoreDNS在kubernetes中的部署

1.查看CoreDNS的官网

点击这里访问CoreDNS的官网。

在CoreDns官网可以查看相关版本以及功能介绍，还可以进入CoreDns的github。

2.查看CoreDNS的github

点击这里访问CoreDNS的github地址。

选择进入deployment，查看如何进行部署的。

3.进入github的deployment

进入deployment页面。

选择进入kubernetes的部署yaml文件

4.查看CoreDNS在kubernetes部署的github脚本文件

进入CoreDNS的kubernetes部署文件页面。

查看kuberntes部署CoreDNS的文件

找到了这里，通过github的介绍说明，基本就可以知道上面的四个文件就是部署所需要的文件，以及如何进行部署的。下面我将文件下载下来，修改一下之后进行部署。

5.下载部署文件

从上面github中，将文件都下载到服务器中。

下载coredns.yaml.sed

apiVersion: v1
kind: ServiceAccount
metadata:name: corednsnamespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:labels:kubernetes.io/bootstrapping: rbac-defaultsname: system:coredns
rules:
- apiGroups:- ""resources:- endpoints- services- pods- namespacesverbs:- list- watch
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:annotations:rbac.authorization.kubernetes.io/autoupdate: "true"labels:kubernetes.io/bootstrapping: rbac-defaultsname: system:coredns
roleRef:apiGroup: rbac.authorization.k8s.iokind: ClusterRolename: system:coredns
subjects:
- kind: ServiceAccountname: corednsnamespace: kube-system
---
apiVersion: v1
kind: ConfigMap
metadata:name: corednsnamespace: kube-system
data:Corefile: |.:53 {errorshealthkubernetes CLUSTER_DOMAIN REVERSE_CIDRS {pods insecureupstreamfallthrough in-addr.arpa ip6.arpa}FEDERATIONSprometheus :9153proxy . UPSTREAMNAMESERVERcache 30loopreloadloadbalance}STUBDOMAINS
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:name: corednsnamespace: kube-systemlabels:k8s-app: kube-dnskubernetes.io/name: "CoreDNS"
spec:replicas: 2strategy:type: RollingUpdaterollingUpdate:maxUnavailable: 1selector:matchLabels:k8s-app: kube-dnstemplate:metadata:labels:k8s-app: kube-dnsspec:serviceAccountName: corednstolerations:- key: node-role.kubernetes.io/mastereffect: NoSchedule- key: "CriticalAddonsOnly"operator: "Exists"containers:- name: corednsimage: coredns/coredns:1.2.2imagePullPolicy: IfNotPresentresources:limits:memory: 170Mirequests:cpu: 100mmemory: 70Miargs: [ "-conf", "/etc/coredns/Corefile" ]volumeMounts:- name: config-volumemountPath: /etc/corednsreadOnly: trueports:- containerPort: 53name: dnsprotocol: UDP- containerPort: 53name: dns-tcpprotocol: TCP- containerPort: 9153name: metricsprotocol: TCPsecurityContext:allowPrivilegeEscalation: falsecapabilities:add:- NET_BIND_SERVICEdrop:- allreadOnlyRootFilesystem: truelivenessProbe:httpGet:path: /healthport: 8080scheme: HTTPinitialDelaySeconds: 60timeoutSeconds: 5successThreshold: 1failureThreshold: 5dnsPolicy: Defaultvolumes:- name: config-volumeconfigMap:name: corednsitems:- key: Corefilepath: Corefile
---
apiVersion: v1
kind: Service
metadata:name: kube-dnsnamespace: kube-systemannotations:prometheus.io/port: "9153"prometheus.io/scrape: "true"labels:k8s-app: kube-dnskubernetes.io/cluster-service: "true"kubernetes.io/name: "CoreDNS"
spec:selector:k8s-app: kube-dnsclusterIP: CLUSTER_DNS_IPports:- name: dnsport: 53protocol: UDP- name: dns-tcpport: 53protocol: TCP

下载deploy.sh部署配置脚本。

#!/bin/bash# Deploys CoreDNS to a cluster currently running Kube-DNS.show_help () {
cat << USAGE
usage: $0 [ -r REVERSE-CIDR ] [ -i DNS-IP ] [ -d CLUSTER-DOMAIN ] [ -t YAML-TEMPLATE ] [ -k KUBECONFIG ]-r : Define a reverse zone for the given CIDR. You may specifcy this option morethan once to add multiple reverse zones. If no reverse CIDRs are defined,then the default is to handle all reverse zones (i.e. in-addr.arpa and ip6.arpa)-i : Specify the cluster DNS IP address. If not specificed, the IP address ofthe existing "kube-dns" service is used, if present.-s : Skips the translation of kube-dns configmap to the corresponding CoreDNS Corefile configuration.
USAGE
exit 0
}# Simple Defaults
CLUSTER_DOMAIN=cluster.local
YAML_TEMPLATE=`pwd`/coredns.yaml.sed
STUBDOMAINS=""
UPSTREAM=\\/etc\\/resolv\.conf
FEDERATIONS=""# Translates the kube-dns ConfigMap to equivalent CoreDNS Configuration.
function translate-kube-dns-configmap {kube-dns-federation-to-corednskube-dns-upstreamnameserver-to-corednskube-dns-stubdomains-to-coredns
}function kube-dns-federation-to-coredns {fed=$(kubectl -n kube-system get configmap kube-dns  -ojsonpath='{.data.federations}' 2> /dev/null | jq . | tr -d '":,')if [[ ! -z ${fed} ]]; thenFEDERATIONS=$(sed -e '1s/^/federation /' -e 's/^/        /' -e '1i\\' <<< "${fed}") # add federation to the stanzafi
}function kube-dns-upstreamnameserver-to-coredns {up=$(kubectl -n kube-system get configmap kube-dns  -ojsonpath='{.data.upstreamNameservers}' 2> /dev/null | tr -d '[",]')if [[ ! -z ${up} ]]; thenUPSTREAM=${up}fi
}function kube-dns-stubdomains-to-coredns {STUBDOMAIN_TEMPLATE='SD_DOMAIN:53 {errorscache 30loopproxy . SD_DESTINATION}'function dequote {str=${1#\"} # delete leading quotestr=${str%\"} # delete trailing quoteecho ${str}}function parse_stub_domains() {sd=$1# get keys - each key is a domainsd_keys=$(echo -n $sd | jq keys[])# For each domain ...for dom in $sd_keys; dodst=$(echo -n $sd | jq '.['$dom'][0]') # get the destinationdom=$(dequote $dom)dst=$(dequote $dst)sd_stanza=${STUBDOMAIN_TEMPLATE/SD_DOMAIN/$dom} # replace SD_DOMAINsd_stanza=${sd_stanza/SD_DESTINATION/$dst} # replace SD_DESTINATIONecho "$sd_stanza"done
}sd=$(kubectl -n kube-system get configmap kube-dns  -ojsonpath='{.data.stubDomains}' 2> /dev/null)STUBDOMAINS=$(parse_stub_domains "$sd")
}# Get Opts
while getopts "hsr:i:d:t:k:" opt; docase "$opt" inh)  show_help;;s)  SKIP=1;;r)  REVERSE_CIDRS="$REVERSE_CIDRS $OPTARG";;i)  CLUSTER_DNS_IP=$OPTARG;;d)  CLUSTER_DOMAIN=$OPTARG;;t)  YAML_TEMPLATE=$OPTARG;;k)  KUBECONFIG=$OPTARG;;esac
done# Set kubeconfig flag if config specified
if [[ ! -z $KUBECONFIG ]]; thenif [[ -f $KUBECONFIG ]]; thenKUBECONFIG="--kubeconfig $KUBECONFIG"elseKUBECONFIG=""fi
fi
# Conditional Defaults
if [[ -z $REVERSE_CIDRS ]]; thenREVERSE_CIDRS="in-addr.arpa ip6.arpa"
fi
if [[ -z $CLUSTER_DNS_IP ]]; then# Default IP to kube-dns IPCLUSTER_DNS_IP=$(kubectl get service --namespace kube-system kube-dns -o jsonpath="{.spec.clusterIP}" $KUBECONFIG)if [ $? -ne 0 ]; then>&2 echo "Error! The IP address for DNS service couldn't be determined automatically. Please specify the DNS-IP with the '-i' option."exit 2fi
fiif [[ "${SKIP}" -ne 1 ]] ; thentranslate-kube-dns-configmap
fiorig=$'\n'
replace=$'\\\n'
sed -e "s/CLUSTER_DNS_IP/$CLUSTER_DNS_IP/g" \-e "s/CLUSTER_DOMAIN/$CLUSTER_DOMAIN/g" \-e "s?REVERSE_CIDRS?$REVERSE_CIDRS?g" \-e "s@STUBDOMAINS@${STUBDOMAINS//$orig/$replace}@g" \-e "s@FEDERATIONS@${FEDERATIONS//$orig/$replace}@g" \-e "s/UPSTREAMNAMESERVER/$UPSTREAM/g" \"${YAML_TEMPLATE}"

6.配置文件并部署服务

首先第一步要知道集群使用的DNS的IP地址

从kubelet配置中可以得知集群配置的clusterIP地址是10.0.6.200

查看delpoy脚本，确定执行过程

总结需要修改下面几个配置：

sed 
-e s/CLUSTER_DNS_IP/$CLUSTER_DNS_IP/g 
-e s/CLUSTER_DOMAIN/$CLUSTER_DOMAIN/g 
-e "s?REVERSE_CIDRS?$REVERSE_CIDRS?g" 
$YAML_TEMPLATE其中REVERSE_CIDRS就是上游的IP地址。
in-addr.arpa ip6.arpa

查看配置在模板yaml文件的位置

编写自定义配置脚本

代码如下：

[root@server81 install_CoreDNS]# vim set_coredns_param.sh #!/bin/bash
basedir=$(cd `dirname $0`;pwd)REVERSE_CIDRS="10.0.6.0/24" ## 配置 kubernetes svc 网段
CLUSTER_DNS_IP="10.0.6.200" ## 配置 kubernetes DNS IP
CLUSTER_DOMAIN="cluster.local" ## 配置 kubernetes 的域名
YAML_TEMPLATE=$basedir/coredns.yaml.sed ## coredns 的模板yaml文件## function
function create_coredns_yaml(){
local TEMPLATE=$basedir/coredns.yaml.simple
local YAML=$basedir/coredns.yaml
cat $YAML_TEMPLATE > $TEMPLATEsed -e s/CLUSTER_DNS_IP/$CLUSTER_DNS_IP/g -e s/CLUSTER_DOMAIN/$CLUSTER_DOMAIN/g -e "s?REVERSE_CIDRS?$REVERSE_CIDRS?g"  $TEMPLATE > $YAML}create_coredns_yaml

执行配置脚本，生成部署coreDNS.yaml文件

下载镜像，并推送至本地的私有仓库

image: coredns/coredns:1.2.0

这里就不说明如何推送镜像到仓库的步骤了。

修改coredns.yaml文件中的镜像地址

执行部署

查看部署服务是否正常

服务已经正常运行，那么下面进入容器内ping一下域名，确认是否解析成功了。

再次进入容器内ping域名，确认是否解析成功