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

学习目标

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

准备环境

环境说明:

系统	主机名	IP地址
centos8	master	192.168.71.134
centos8	node1	192.168.71.136
centos8	node2	192.168.71.138

准备工作
以下操做三台主机都要做

// 关闭防火墙和selinux
[root@localhost ~]# systemctl disable --now firewalld

[root@localhost ~]# cat /etc/selinux/config 

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing - SELinux security policy is enforced.
#     permissive - SELinux prints warnings instead of enforcing.
#     disabled - No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of these three values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected. 
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted

// 修改主机名
[root@master ~]# hostname
master.example.com

// 关闭swap分区
[root@master ~]# vim /etc/fstab
#/dev/mapper/cs-swap     none                    swap    defaults        0 0  //注释此行

// 时间同步
[root@master ~]# yum -y install chrony
cento7上添加 server time1.aliyun.com iburst
[root@master ~]# vim /etc/chrony.conf 
  2 # Please consider joining the pool (http://www.pool.ntp.org/join.html).
  3 pool time1.aliyun.com iburst  //添加此行内容
[root@master ~]# systemctl enable --now chronyd 

master端：
// 在master上添加hosts

[root@master ~]# cat /etc/hosts 
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.71.134 master master.example.com
192.168.71.136 node1 node1.example.com
192.168.71.138 node2 node2.example.com

// 将桥接的IPv4流量传递到iptables的链

[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  //使其生效

// 做免密登录

[root@master ~]# ssh-keygen -t  rsa
[root@master ~]# ssh-copy-id master
[root@master ~]# ssh-copy-id node1
[root@master ~]# ssh-copy-id node2

所有节点安装Docker/kubeadm/kubelet

安装docker

Kubernetes默认CRI（容器运行时）为Docker，因此先安装Docker。
都要安装docker
[root@master ~]# yum -y install yum-utils
[root@master yum.repos.d]# yum-config-manager --add-repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
[root@master ~]# sed -i 's+download.docker.com+mirrors.aliyun.com/docker-ce+' /etc/yum.repos.d/docker-ce.repo

[root@master ~]# yum -y install docker-ce-3:19.03.15-3.el8
[root@master ~]# systemctl enable --now docker.service

[root@master ~]# cat > /etc/docker/daemon.json << EOF
> {
>   "registry-mirrors": ["这里时阿里云的镜像加速地址"],
>   "exec-opts": ["native.cgroupdriver=systemd"],
>   "log-driver": "json-file",
>   "log-opts": {
>     "max-size": "100m"
>   },
> "storage-driver": "overlay2"
> }
> EOF

[root@master ~]# systemctl daemon-reload 
[root@master ~]# systemctl restart docker.service

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

安装kubeadm，kubelet和kubectl

指定版本号部署：

[root@master ~]# yum install -y kubelet-1.20.0 kubeadm-1.20.0 kubectl-1.20.0

[root@master ~]# systemctl enable kubelet  //设置开机自启
[root@master ~]# reboot

部署Kubernetes Master

在Master端执行

[root@master ~]# kubeadm init --apiserver-advertise-address 192.168.71.134 --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
[init] Using Kubernetes version: v1.20.0
[preflight] Running pre-flight checks
	[WARNING FileExisting-tc]: tc not found in system path
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local master.example.com] and IPs [10.96.0.1 192.168.71.134]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [localhost master.example.com] and IPs [192.168.71.134 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [localhost master.example.com] and IPs [192.168.71.134 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Starting the kubelet
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[apiclient] All control plane components are healthy after 16.503304 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.20" in namespace kube-system with the configuration for the kubelets in the cluster
[upload-certs] Skipping phase. Please see --upload-certs
[mark-control-plane] Marking the node master.example.com as control-plane by adding the labels "node-role.kubernetes.io/master=''" and "node-role.kubernetes.io/control-plane='' (deprecated)"
[mark-control-plane] Marking the node master.example.com as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: apjjye.qn44n10fexo5jpjw
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to get nodes
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy

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  //设置环境变量

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:
// 保存以下内容
kubeadm join 192.168.71.134:6443 --token apjjye.qn44n10fexo5jpjw \
    --discovery-token-ca-cert-hash sha256:aa4d039a0212dcfb9644b949358a6a333c24745770a5f9873c6428ccf8b45f24

// 因为每台主机生成的内容不同。
[root@master ~]# cat k8s 
kubeadm join 192.168.71.134:6443 --token apjjye.qn44n10fexo5jpjw \
    --discovery-token-ca-cert-hash sha256:aa4d039a0212dcfb9644b949358a6a333c24745770a5f9873c6428ccf8b45f24

// 查看镜像
[root@master ~]# docker images 
REPOSITORY                                                        TAG        IMAGE ID       CREATED         SIZE
registry.aliyuncs.com/google_containers/kube-proxy                v1.20.0    10cc881966cf   12 months ago   118MB
registry.aliyuncs.com/google_containers/kube-apiserver            v1.20.0    ca9843d3b545   12 months ago   122MB
registry.aliyuncs.com/google_containers/kube-controller-manager   v1.20.0    b9fa1895dcaa   12 months ago   116MB
registry.aliyuncs.com/google_containers/kube-scheduler            v1.20.0    3138b6e3d471   12 months ago   46.4MB
registry.aliyuncs.com/google_containers/etcd                      3.4.13-0   0369cf4303ff   15 months ago   253MB
registry.aliyuncs.com/google_containers/coredns                   1.7.0      bfe3a36ebd25   18 months ago   45.2MB
registry.aliyuncs.com/google_containers/pause                     3.2        80d28bedfe5d   22 months ago   683kB

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

[root@master ~]# source /etc/profile.d/k8s.sh //使其快速生效
[root@master ~]# echo $KUBECONFIG   //检查是否生效
/etc/kubernetes/admin.conf

安装Pod网络插件（CNI）

[root@master ~]# kubectl edit cm kube-proxy -n kube-system
// 修改mode：“ipvs”
[root@master ~]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Docum
entation/kube-flannel.yml

加入Kubernetes Node

在node节点上执行
向集群添加新节点，执行在kubeadm init输出的kubeadm join命令：

// 这里执行的就是我们刚才保存的k8s文件里面的内容

[root@node1 ~]# kubeadm join 192.168.71.134:6443 --token apjjye.qn44n10fexo5jpjw \
>     --discovery-token-ca-cert-hash sha256:aa4d039a0212dcfb9644b949358a6a333c24745770a5f9873c6428ccf8b45f24
[preflight] Running pre-flight checks
	[WARNING FileExisting-tc]: tc not found in system path
	[WARNING Hostname]: hostname "node1.example.com" could not be reached
	[WARNING Hostname]: hostname "node1.example.com": lookup node1.example.com on 192.168.71.2:53: no such host
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the control-plane to see this node join the cluster.

// 在node2上执行
[root@node2 ~]# kubeadm join 192.168.71.134:6443 --token apjjye.qn44n10fexo5jpjw \
>     --discovery-token-ca-cert-hash sha256:aa4d039a0212dcfb9644b949358a6a333c24745770a5f9873c6428ccf8b45f24
[preflight] Running pre-flight checks
	[WARNING FileExisting-tc]: tc not found in system path
	[WARNING Hostname]: hostname "node2.example.com" could not be reached
	[WARNING Hostname]: hostname "node2.example.com": lookup node2.example.com on 192.168.71.2:53: no such host
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the control-plane to see this node join the cluster.

测试kubernetes集群

// 查看节点的状态
[root@master ~]# kubectl get nodes
NAME                 STATUS   ROLES                  AGE     VERSION
master.example.com   Ready    control-plane,master   75m     v1.20.0
node1.example.com    Ready    <none>                 4m42s   v1.20.0
node2.example.com    Ready    <none>                 103s    v1.20.0

[root@master ~]# kubectl create deployment nginx --image=nginx  //运行一个nginx的pod
deployment.apps/nginx created
[root@master ~]# kubectl expose deployment nginx --port=80 --type=NodePort  //映射80端口
service/nginx exposed

[root@master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1     <none>        443/TCP        77m
nginx        NodePort    10.99.74.11   <none>        80:31173/TCP   32s

[root@master ~]# curl 10.99.74.11
<!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>