#云原生征文# 单Master集群安装（k8s） 原创

1. 服务器要求：

• 建议最小硬件配置：2核CPU、2G内存、20G硬盘

• 服务器最好可以访问外网，会有从网上拉取镜像需求，如果服务器不能上网，需要提前下载对应镜像并导入节点

1.1 软件环境：

软件	版本
操作系统	CentOS7.9_x64 （mini）
Docker	19-ce
Kubernetes	1.20

1.2 服务器规划：

角色	IP
k8s-master1	192.168.137.81
k8s-node1	192.168.137.82
k8s-node2	192.168.137.83

1.3 架构图：

2. 操作系统初始化配置

# 关闭防火墙
systemctl stop firewalld
systemctl disable firewalld

# 关闭selinux
sed -i '/^SELINUX/s/enforcing/disabled/' /etc/selinux/config  # 永久
setenforce 0  # 临时

# 关闭swap
swapoff -a  # 临时
sed -ri 's/.*swap.*/#&/' /etc/fstab    # 永久

# 根据规划设置主机名
hostnamectl set-hostname <hostname>

# 在master添加hosts
cat >> /etc/hosts << EOF
192.168.137.81 k8s-master1
192.168.137.82 k8s-node1
192.168.137.83 k8s-node2
EOF

# 将桥接的IPv4流量传递到iptables的链
cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system  # 生效

# 时间同步
yum install ntpdate -y
ntpdate time.windows.com

3. 安装Docker/kubeadm/kubelet [所有节点]

这里使用Docker作为容器引擎，也可以换成别的，例如containerd

3.1 安装Docker

wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
yum -y install docker-ce
systemctl enable docker && systemctl start docker

3.2 配置镜像下载加速器

sudo mkdir -p /etc/docker
sudo tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://v27k018o.mirror.aliyuncs.com"]
}
EOF
sudo systemctl daemon-reload
sudo systemctl restart docker

3.3 添加阿里云YUM软件源

cat > /etc/yum.repos.d/kubernetes.repo << EOF
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

3.4 安装kubeadm，kubelet，kubectl

指定需安装版本号进行部署

yum install -y kubelet-1.20.0 kubeadm-1.20.0 kubectl-1.20.0
systemctl enable kubelet

4. 部署Kubernetes Master

在192.168.137.81（Master）执行

kubeadm init \
  --apiserver-advertise-address=192.168.137.81 \
  --image-repository registry.aliyuncs.com/google_containers \
  --kubernetes-version v1.20.0 \
  --service-cidr=10.96.0.0/12 \
  --pod-network-cidr=10.244.0.0/16 \
  --ignore-preflight-errors=all

• --apiserver-advertise-address 集群通告地址

• --image-repository 由于默认拉取镜像地址k8s.gcr.io国内无法访问，这里指定阿里云镜像仓库地址

• --kubernetes-version K8s版本，与上面安装的一致

• --service-cidr 集群内部虚拟网络，Pod统一访问入口

• --pod-network-cidr Pod网络，，与下面部署的CNI网络组件yaml中保持一致

或者使用配置文件引导：

# cat kubeadm.conf
apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
kubernetesVersion: v1.20.0
imageRepository: registry.aliyuncs.com/google_containers 
networking:
  podSubnet: 10.244.0.0/16 
  serviceSubnet: 10.96.0.0/12 

# kubeadm init --config kubeadm.conf --ignore-preflight-errors=all

初始化完成后，最后会输出一个join命令，先记住，下面用。

Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

Alternatively, if you are the root user, you can run:

  export KUBECONFIG=/etc/kubernetes/admin.conf

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 192.168.137.81:6443 --token tix7ff.pnjcwvl6awyaeh8i \
    --discovery-token-ca-cert-hash sha256:617842ea5040ce5e7f971d387b58693cbfa79261763b68c589fe8d124f1a5154

拷贝kubectl使用的连接k8s认证文件到默认路径：

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

查看工作节点：

[root@k8s-master ~]# kubectl get nodes
NAME          STATUS     ROLES                  AGE   VERSION
k8s-master1   NotReady   control-plane,master   95s   v1.20.0

注：由于网络插件还没有部署，还没有准备就绪 NotReady
参考资料：
https://kubernetes.io/zh/docs/reference/setup-tools/kubeadm/kubeadm-init/#config-file
https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/#initializing-your-control-plane-node

5. 加入Kubernetes Node节点

在192.168.137.82/83 (Node) 执行
向集群添加新节点，执行在kubeadm init输出的kubeadm join命令：

kubeadm join 192.168.137.81:6443 --token tix7ff.pnjcwvl6awyaeh8i \
    --discovery-token-ca-cert-hash sha256:617842ea5040ce5e7f971d387b58693cbfa79261763b68c589fe8d124f1a5154

默认token有效期为24小时，当过期之后，该token就不可用了。这时就需要重新创建token，可以直接使用命令快捷生成：

kubeadm token create --print-join-command

参考资料：https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-join/

6. 部署容器网络（CNI）

Calico是一个纯三层的数据中心网络方案，是目前Kubernetes主流的网络方案。
下载YAML：

wget https://docs.projectcalico.org/manifests/calico.yaml

下载完后还需要修改里面定义Pod网络（CALICO_IPV4POOL_CIDR），与前面kubeadm init的 --pod-network-cidr指定的一样。

修改完后文件后，部署：

kubectl apply -f calico.yaml
kubectl get pods -n kube-system

等Calico Pod都Running，节点也会准备就绪：
参考资料：https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/#pod-network

[root@k8s-master ~]# kubectl get pods -n kube-system
NAME                                       READY   STATUS    RESTARTS   AGE
calico-kube-controllers-5f6cfd688c-4hfmv   1/1     Running   0          2m37s
calico-node-8swrp                          1/1     Running   0          2m37s
calico-node-nv96p                          1/1     Running   0          2m37s
calico-node-s2vl6                          1/1     Running   0          2m37s
coredns-7f89b7bc75-7nzm8                   0/1     Running   0          22m
coredns-7f89b7bc75-9c46c                   0/1     Running   0          22m
etcd-k8s-master1                           1/1     Running   0          22m
kube-apiserver-k8s-master1                 1/1     Running   0          22m
kube-controller-manager-k8s-master1        1/1     Running   0          22m
kube-proxy-clc6k                           1/1     Running   0          18m
kube-proxy-dvlvr                           1/1     Running   0          22m
kube-proxy-jr6hm                           1/1     Running   0          18m
kube-scheduler-k8s-master1                 1/1     Running   0          22m
[root@k8s-master ~]# kubectl get nodes
NAME          STATUS   ROLES                  AGE   VERSION
k8s-master1   Ready    control-plane,master   23m   v1.20.0
k8s-node1     Ready    <none>                 18m   v1.20.0
k8s-node2     Ready    <none>                 18m   v1.20.0

7. 测试kubernetes集群

在Kubernetes集群中创建一个pod，验证是否正常运行：

kubectl create deployment nginx --image=nginx
kubectl expose deployment nginx --port=80 --type=NodePort
kubectl get pod,svc

[root@k8s-master ~]# kubectl get pod,svc
NAME                         READY   STATUS    RESTARTS   AGE
pod/nginx-6799fc88d8-nkzk6   1/1     Running   0          6m51s

NAME                 TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP        32m
service/nginx        NodePort    10.108.121.252   <none>        80:30167/TCP   6m2s

访问地址：http://NodeIP:Port

8. 部署Dashboard

Dashboard是官方提供的一个UI，可用于基本管理K8s资源。

wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.3/aio/deploy/recommended.yaml

默认Dashboard只能集群内部访问，修改Service为NodePort类型，暴露到外部：

# vi recommended.yaml
...
kind: Service
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kubernetes-dashboard
spec:
  ports:
    - port: 443
      targetPort: 8443
      nodePort: 30001
  selector:
    k8s-app: kubernetes-dashboard
  type: NodePort
...

# kubectl apply -f recommended.yaml
# kubectl get pods -n kubernetes-dashboard

访问地址：https://NodeIP:30001

创建service account并绑定默认cluster-admin管理员集群角色：

# 创建用户
$ kubectl create serviceaccount dashboard-admin -n kube-system
# 用户授权
$ kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin --serviceaccount=kube-system:dashboard-admin
# 获取用户Token
$ kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}')

使用输出的token登录Dashboard。

[root@k8s-master ~]# kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}')
Name:         dashboard-admin-token-cgmld
Namespace:    kube-system
Labels:       <none>
Annotations:  kubernetes.io/service-account.name: dashboard-admin
              kubernetes.io/service-account.uid: 3208e176-5115-4425-bb67-d45863bc05f7

Type:  kubernetes.io/service-account-token

Data
====
ca.crt:     1066 bytes
namespace:  11 bytes
token:      eyJhbGciOiJSUzI1NiIsImtpZCI6IlBnN2lzMk8zYndPX3ZONnc0cnFnRjhsVnczOTVlNGxXSDl4c1Z0OGtmNDAifQ.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.DY9SLeakUzVUqUHLJjLuaBtv0EOj6l-zsCfmzKTtsiTkaX39bGpLInToKuSpbXHYAmkpCvoZH22ghmOds3LFgvQBCIt6M83rrL83aPzhDjAKtPtPkz9vJGR7K5LnfrB9AX5dVhiU_AkaVIBIFcqTxVlFpl6W1EzTc0uJDM7K8Gr2XnPvRfUMe8WaEWR7tVxMEEhPhP2waEYmcc5uFz5unI_g6lTMYRJnhZCjfqh7lS9NA_8WgmoQnQjxW4cYAsqrdCzbroTEMCslH_pCj-PZNxf7mKVXZwklYL78t8klU_AytuhdaV88iRR3HEuBMYLbfJjy6RLkyt_ORweaXb8npg

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