一、概述
一般情况下，在k8smaster节点上集群管理工具kubectl是连接的本地http8080端口和apiserver进行通讯的,当然也可以通过https端口进行通讯前提是要生成证书。所以说kubectl不一定部署在master上，只要能和apiserver进行通讯，那么你可以将kubectl部署在任何一台你想连接到集群的主机上，以下将介绍基于证书的kubectl部署方式，以下基于kubernets1.13部署。
二、生成ca证书
如果已经有了ca证书那就不需要在生成了，只需要利用该证书生成admin证书即可。
安装生成证书工具
wget https://pkg.cfssl.org/R1.2/cfssl_linux-amd64
wget https://pkg.cfssl.org/R1.2/cfssljson_linux-amd64
wget https://pkg.cfssl.org/R1.2/cfssl-certinfo_linux-amd64
chmod +x cfssl_linux-amd64 cfssljson_linux-amd64 cfssl-certinfo_linux-amd64 mv cfssl_linux-amd64 /usr/local/bin/cfssl
mv cfssljson_linux-amd64 /usr/local/bin/cfssljson
mv cfssl-certinfo_linux-amd64 /usr/bin/cfssl-certinfo
生成ca配置
cat > ca-config.json <<EOF
{
"signing": {
"default": {
"expiry": "87600h"
},
"profiles": {
"kubernetes": {
"expiry": "87600h",
"usages": [
"signing",
"key encipherment",
"server auth",
"client auth"
]
}
}
}
}
EOF
生成csr配置
cat > ca-csr.json <<EOF
{
"CN": "kubernetes",
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "CN",
"L": "Beijing",
"ST": "Beijing",
"O": "k8s",
"OU": "System"
}
]
}
EOF
生成ca证书
cfssl gencert -initca ca-csr.json | cfssljson -bare ca -
三、生成admin证书
证书配置
cat > admin-csr.json <<EOF
{
"CN": "admin",
"hosts": [],
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "CN",
"L": "BeiJing",
"ST": "BeiJing",
"O": "system:masters",
"OU": "System"
}
]
}
EOF
生成证书
[root@master master]# cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=kubernetes admin-csr.json | cfssljson -bare admin
2019/01/09 15:25:20 [INFO] generate received request
2019/01/09 15:25:20 [INFO] received CSR
2019/01/09 15:25:20 [INFO] generating key: rsa-2048
2019/01/09 15:25:20 [INFO] encoded CSR
2019/01/09 15:25:20 [INFO] signed certificate with serial number 496018729932380195936891977997946670147442472383
2019/01/09 15:25:20 [WARNING] This certificate lacks a "hosts" field. This makes it unsuitable for
websites. For more information see the Baseline Requirements for the Issuance and Management
of Publicly-Trusted Certificates, v.1.1.6, from the CA/Browser Forum (https://cabforum.org);
specifically, section 10.2.3 ("Information Requirements").
查看证书
[root@master master]# ls admin*
admin.csr admin-csr.json admin-key.pem admin.pem
四、配置kubectl
拷贝证书以及相关kubectl到目标机器
scp /opt/kubernetes/bin/kubectl 10.1.210.32:/usr/bin #拷贝命令
scp admin* ca.pem 10.1.210.32:/opt/kubernetes/kubectl/ssl # 拷贝证书
配置kubectl配置文件
#进入证书目录
cd /opt/kubernetes/kubectl/ssl #生成kubectl配置文件
kubectl config set-cluster kubernetes --server=https://10.1.210.33:6443 --certificate-authority=ca.pem #设置用户项中cluster-admin用户证书认证字段
kubectl config set-credentials cluster-admin --certificate-authority=ca.pem --client-key=admin-key.pem --client-certificate=admin.pem #设置默认上下文
kubectl config set-context default --cluster=kubernetes --user=cluster-admin #设置当前环境的default
kubectl config use-context default
查看配置文件
[root@node1 ssl]# cat /root/.kube/config
apiVersion: v1
clusters:
- cluster:
certificate-authority: /opt/kubernetes/kubectl/ssl/ca.pem
server: https://10.1.210.33:6443
name: kubernetes
contexts:
- context:
cluster: kubernetes
user: cluster-admin
name: default
current-context: default
kind: Config
preferences: {}
users:
- name: cluster-admin
user:
client-certificate: /opt/kubernetes/kubectl/ssl/admin.pem
client-key: /opt/kubernetes/kubectl/ssl/admin-key.pem
五、管理集群