使用 kubeadm 搭建Kubernetes 1.18单节点集群实战（基于Oracle Linux 8.1）

# 使用 kubeadm 搭建Kubernetes 1.19.0单节点集群实战（基于CentOS Linux release 8.2.2004 (Core)）：https://blog.csdn.net/engchina/article/details/108302306

# 搭建Kubernetes 1.19.0单节点集群实战录屏视频请访问：https://www.bilibili.com/video/bv1Pf4y1X7js

 

详细步骤：

 

1，把IP地址改为192.168.56.118，然后修改hosts

 

sudo su -

 

vi /etc/hosts

 

追加enp0s8的ip和hostname，例如

 

192.168.56.118 k8s118-master

 

hostnamectl set-hostname k8s118-master

 

2，创建install-k8s.sh

 

export PUBLIC_IP=YOUR_PUBLIC_IP # or DNS_NAME of YOUR_PUBLIC_IP

 

vi install-public-k8s.sh

 

#!/bin/bash

echo "Start"

dnf config-manager --set-enabled ol8_u1_baseos_base
dnf config-manager --set-enabled ol8_addons
dnf remove podman -y

export IP_ADDR=$(ip addr show enp0s8 | grep -Po 'inet \K[\d.]+')
echo $IP_ADDR

sudo su - << FOE

# Stop firewall and selinux
sudo systemctl disable --now firewalld
sudo /usr/sbin/setenforce 0
sudo sed -i 's/SELINUX=enforcing/SELINUX=permissive/g' /etc/selinux/config

# Ignore Swap Error while installing kubernetes cluster with Swap
cat<<EOF > /etc/sysconfig/kubelet
KUBELET_EXTRA_ARGS=--fail-swap-on=false
EOF

# Install neccessary system tools
sudo yum install -y dnf-utils

# Open ipvs
cat <<EOF >/etc/sysconfig/modules/ipvs.modules
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
EOF

sudo chmod 755 /etc/sysconfig/modules/ipvs.modules
sudo bash /etc/sysconfig/modules/ipvs.modules
sudo lsmod | grep -e ip_vs -e nf_conntrack_ipv4
sudo dnf install ipset ipvsadm -y

# Config iptables
echo "br_netfilter" > /etc/modules-load.d/br_netfilter.conf
cat<<EOF > /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF

sudo modprobe br_netfilter
sudo sysctl --system

# Add Docker Repo
sudo dnf config-manager --add-repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
# Install Docker-CE
sudo dnf makecache timer
sudo dnf -y install https://download.docker.com/linux/centos/7/x86_64/stable/Packages/containerd.io-1.2.6-3.3.el7.x86_64.rpm
sudo dnf -y install docker-ce
#sudo dnf -y install --nobest docker-ce
# Enable Docker
sudo systemctl enable --now docker
# Config Docker
if [ ! -d "/etc/docker" ]; then
  mkdir /etc/docker
fi

cat<<EOF > /etc/docker/daemon.json
{
   "exec-opts": ["native.cgroupdriver=systemd"],
   "log-driver": "json-file",
   "log-opts": {
     "max-size": "100m"
   },
   "storage-driver": "overlay2",
   "storage-opts": [
     "overlay2.override_kernel_check=true"
   ],
   "registry-mirrors": ["https://docker.mirrors.ustc.edu.cn"]
}
EOF

sudo systemctl daemon-reload
sudo systemctl restart docker

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

sudo dnf install -y kubeadm kubectl kubelet
sudo systemctl enable kubelet

cat <<EOF > kubeadm-config.yaml
apiVersion: kubeadm.k8s.io/v1beta2
kind: InitConfiguration
localAPIEndpoint:
  advertiseAddress: $IP_ADDR
  bindPort: 6443
---
apiServer:
  timeoutForControlPlane: 4m0s
  certSANs:
  - ${PUBLIC_IP}
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns:
  type: CoreDNS
etcd:
  local:
    dataDir: /var/lib/etcd
    serverCertSANs:
    - $PUBLIC_IP
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
kubernetesVersion: v1.18.0
networking:
  dnsDomain: cluster.local
  serviceSubnet: 10.1.0.0/16
  podSubnet: 10.244.0.0/16
---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
mode: ipvs
EOF

# Create Kubernetes Cluster
#kubeadm init --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=$IP_ADDR --kubernetes-version stable-1.18 --ignore-preflight-errors=Swap --image-repository registry.aliyuncs.com/google_containers --config kubeadm-config.yaml
kubeadm init --config kubeadm-config.yaml --ignore-preflight-errors=Swap

FOE

sleep 10s

# Add User to docker group
sudo usermod -a -G docker $(id -nu)

# Create .kube folder
if [ -f $HOME/.kube/config ]; then
  rm -rf $HOME/.kube/config
fi

if [ ! -d $HOME/.kube ]; then
  mkdir $HOME/.kube
fi

# Copy Kubernetes config file
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

# Apply network plugin
result=1
while [ $result -ne 0 ]
do
#https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
        curl https://docs.projectcalico.org/v3.10/manifests/calico.yaml -O
        sed -i -e "s?192.168.0.0/16?10.244.0.0/16?g" calico.yaml
        kubectl apply -f calico.yaml
        result=$?
        sleep 20s
done

# Taint master node
kubectl taint nodes --all node-role.kubernetes.io/master-

echo "Complete"

 

3，执行install-public-k8s.sh

 

chmod +x install-public-k8s.sh
./install-public-k8s.sh

 

4，查看nodes

 

kubectl get nodes

 

结果

 

NAME            STATUS   ROLES    AGE    VERSION
k8s118-master   Ready    master   6m8s   v1.18.0

 

5，查看所用pods

 

kubectl get pods -A

 

结果

 

NAMESPACE     NAME                                      READY   STATUS    RESTARTS   AGE
kube-system   calico-kube-controllers-dc4469c7f-gqmlg   1/1     Running   0          6m16s
kube-system   calico-node-gqsnq                         1/1     Running   0          6m16s
kube-system   coredns-7ff77c879f-d2zfv                  1/1     Running   0          6m16s
kube-system   coredns-7ff77c879f-fksml                  1/1     Running   0          6m16s
kube-system   etcd-k8s118-master                        1/1     Running   0          6m29s
kube-system   kube-apiserver-k8s118-master              1/1     Running   0          6m29s
kube-system   kube-controller-manager-k8s118-master     1/1     Running   0          6m29s
kube-system   kube-proxy-zt6mf                          1/1     Running   0          6m16s
kube-system   kube-scheduler-k8s118-master              1/1     Running   0          6m29s

 

6，发布一个nginx deployment，进行检证。

 

发布

 

kubectl create deployment nginx --image=nginx

 

查看deployments

 

kubectl get deployments

 

查看deployments的结果

 

NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   1/1     1            1           17s

 

查看pods

 

kubectl get pods -o wide

 

查看pods的结果

 

NAME                    READY   STATUS    RESTARTS   AGE   IP             NODE            NOMINATED NODE   READINESS GATES
nginx-f89759699-49zrf   1/1     Running   0          34s   10.244.76.68   k8s118-master   <none>           <none>

 

用curl访问nginx应用（IP是查看pods的结果的IP值）

 

curl 10.244.0.4

 

curl的结果

 

<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    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>

 

7，为了操作方便，在~/.bashrc中加入如下内容

 

source <(kubectl completion bash)
alias k=kubectl
complete -F __start_kubectl k

 

然后执行

 

source ~/.bashrc

 

这样就可以用k代替kubectl命令了。

 

恭喜，kubernetes 1.18.0正常安装完成。