1 Kubernetes快速部署

kubeadm是官方社区推出的一个用于快速部署kubernetes集群的工具
这个工具能通过两条指令完成一个kubernetes集群的部署

# 创建一个 Master 节点
$ kubeadm init

# 将一个 Node 节点加入到当前集群中
$ kubeadm join <Master节点的IP和端口>

1.1 Kubernetes安装要求

在开始之前，部署Kubernetes集群机器需要满足以下几个条件
至少3台机器，操作系统 CentOS7+

• 硬件配置：2GB或更多RAM，2个CPU或更多CPU，硬盘20GB或更多
• 集群中所有机器之间网络互通
• 可以访问外网，需要拉取镜像
• 禁止swap分区

1.2 安装步骤

• 在所有节点上安装Docker和kubeadm
• 部署Kubernetes Master
• 部署容器网络插件
• 部署 Kubernetes Node，将节点加入Kubernetes集群中
• 部署Dashboard Web页面，可视化查看Kubernetes资源

1.3 准备环境

主机	IP
master	192.168.25.146
node1	192.168.25.147
node2	192.168.25.148

部署

//修改主机名
[root@localhost ~]# hostnamectl set-hostname master.example.com
[root@localhost ~]# bash
[root@master ~]# hostname
master.example.com

[root@node ~]# hostnamectl set-hostname node1.example.com
[root@node ~]# bash
[root@node1 ~]# hostname
node1.example.com

[root@localhost ~]# hostnamectl set-hostname node2.example.com
[root@localhost ~]# bash
[root@node2 ~]# hostname
node2.example.com

#需在三台主机上操作步骤
//关闭防火墙和selinux
[root@master ~]# systemctl disable --now firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@master ~]# sed -i 's/enforcing/disabled/' /etc/selinux/config

//关闭swap分区
# vim /etc/fstab
注释掉swap分区

//添加hosts
[root@master ~]# cat >> /etc/hosts << EOF
192.168.25.146 master master.example.com
192.168.25.147 node1 node1.example.com
192.168.25.148 node2 node2.example.com
EOF

//将桥接的IPv4流量传递到iptables的链(在master上做)
[root@master ~]# cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF

[root@master ~]# sysctl --system     # 生效

//配置时间同步
[root@master ~]# yum -y install chrony
[root@master ~]# vi /etc/chrony.conf 
pool time1.aliyun.com iburst

[root@master ~]# systemctl enable --now chronyd

[root@master ~]# for i in master node1 node2 ;do ssh $i 'date' ;done
2021年 12月 18日 星期六 04:59:41 EST
2021年 12月 18日 星期六 04:59:42 EST
2021年 12月 18日 星期六 04:59:42 EST


//免密认证(只需要在master上做)
[root@master ~]# ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:3DYIG2AYzaeUUWN8asgfqScnXoRyn+tYGOexy92qhD4 root@master.example.com
The key's randomart image is:
+---[RSA 3072]----+
|  .=+=+          |
|  ..=oo..        |
|   o =o+         |
|  . * *= o       |
|   o.*+oS +      |
|    +*Bo . .     |
|   .o*=.         |
|   .E=.o .       |
|    oo=.o..      |
+----[SHA256]-----+

[root@master ~]# ssh-copy-id master
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@master's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'master'"
and check to make sure that only the key(s) you wanted were added.

[root@master ~]# ssh-copy-id node1
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@node1's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'node1'"
and check to make sure that only the key(s) you wanted were added.

[root@master ~]# ssh-copy-id node2
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@node2's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'node2'"
and check to make sure that only the key(s) you wanted were added.

// 重启三台主机，使上面的一些配置生效
[root@master ~]# reboot

1.4 所有节点安装Docker/kubeadm/kubelet

Kubernetes默认CRI（容器运行时）为Docker，因此先安装Docker。

1.4.1 安装Docker

[root@master ~]# wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
[root@master ~]# yum -y install docker-ce
[root@master ~]# systemctl enable --now docker

[root@master ~]# systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disab>
   Active: active (running) since Sat 2021-12-18 05:10:41 EST; 9s ago
     Docs: https://docs.docker.com
 Main PID: 7143 (dockerd)
    Tasks: 9
   Memory: 36.3M
   CGroup: /system.slice/docker.service
           └─7143 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

12月 18 05:10:40 master.example.com dockerd[7143]: time="2021-12-18T05:10:40.840348434-0>
12月 18 05:10:40 master.example.com dockerd[7143]: time="2021-12-18T05:10:40.865784971-0>
12月 18 05:10:40 master.example.com dockerd[7143]: time="2021-12-18T05:10:40.865832834-0>
12月 18 05:10:40 master.example.com dockerd[7143]: time="2021-12-18T05:10:40.866033860-0>
12月 18 05:10:41 master.example.com dockerd[7143]: time="2021-12-18T05:10:41.040791665-0>
12月 18 05:10:41 master.example.com dockerd[7143]: time="2021-12-18T05:10:41.093668762-0>
12月 18 05:10:41 master.example.com dockerd[7143]: time="2021-12-18T05:10:41.109693941-0>
lines 1-17

[root@master ~]# docker --version
Docker version 20.10.12, build e91ed57


[root@master ~]# cat > /etc/docker/daemon.json << EOF
{
  "registry-mirrors": ["https://xj3hc284.mirror.aliyuncs.com"],
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2"
}
EOF

1.4.2 添加kubernetes阿里云YUM软件源

[root@master ~]# 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

1.4.3 安装kubeadm，kubelet和kubectl

由于版本更新频繁，这里指定版本号部署

[root@node2 ~]# yum install -y kubelet-1.20.0 kubeadm-1.20.0 kubectl-1.20.0
[root@master ~]# systemctl enable kubelet
Created symlink /etc/systemd/system/multi-user.target.wants/kubelet.service → /usr/lib/systemd/system/kubelet.service.

1.5 部署Kubernetes Master

在192.168.25.146（Master）执行

[root@master ~]# kubeadm init \
--apiserver-advertise-address=192.168.25.146 \
--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


 // 记录下面的这些东西到一个文件中，后面会用到
 kubeadm join 192.168.25.146:6443 --token 481ink.zzl4pouej6vq82bs \
    --discovery-token-ca-cert-hash sha256:94dc5e83208b662f4a9f7f133a1da3ed6052ead72922de5aee750ab498d44031 

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

[root@master ~]# echo ‘export KUBECONFIG=/etc/kubernetes/admin.conf' > /etc/profile.d/k8s.sh
[root@master ~]# source /etc/profile.d/k8s.sh

1.6 安装Pod网络插件（CNI）

//使用这条命令直接安装
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

//我这里是把文件下载下来安装
[root@master ~]# ls
anaconda-ks.cfg  kube-flannel.yml

[root@master ~]# kubectl apply -f /root/kube-flannel.yml 
podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created

确保能够访问到quay.io这个registery

1.7 加入Kubernetes Node

在192.168.25.147、192.168.25.148上（Node）执行，执行刚刚保存的命令
向集群添加新节点，执行在kubeadm init输出的kubeadm join命令

[root@node1 ~]#  kubeadm join 192.168.25.146:6443 --token 481ink.zzl4pouej6vq82bs     --discovery-token-ca-cert-hash sha256:94dc5e83208b662f4a9f7f133a1da3ed6052ead72922de5aee750ab498d44031 

[root@node2 ~]#  kubeadm join 192.168.25.146:6443 --token 481ink.zzl4pouej6vq82bs     --discovery-token-ca-cert-hash sha256:94dc5e83208b662f4a9f7f133a1da3ed6052ead72922de5aee750ab498d44031 

2 测试kubernetes集群

在Kubernetes集群中创建一个pod，验证是否正常运行

[root@master ~]# kubectl get nodes
NAME                 STATUS   ROLES                  AGE     VERSION
master.example.com   Ready    control-plane,master   15m     v1.20.0
node1.example.com    Ready    <none>                 5m58s   v1.20.0
node2.example.com    Ready    <none>                 5m53s   v1.20.0

[root@master ~]# kubectl create deployment nginx --image=nginx
deployment.apps/nginx created
[root@master ~]# kubectl expose deployment nginx --port=80 --type=NodePort
service/nginx exposed

[root@master ~]# kubectl get pod,svc
NAME                         READY   STATUS    RESTARTS   AGE
pod/nginx-6799fc88d8-sk9zs   1/1     Running   0          4m56s

NAME                 TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1      <none>        443/TCP        21m
service/nginx        NodePort    10.110.176.8   <none>        80:32279/TCP   4m36s

//访问在pod中运行的容器
[root@master ~]# curl 10.110.176.8
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

在浏览器上访问