Kubernetes first bomb - nanny level installation tutorial

This article has participated in the "Newcomer Creation Ceremony" activity, and started the road of Nuggets creation together

kubernetes, or K8s for short, is an abbreviation that replaces the 8-character "ubernete" with 8. It is an open source, used to manage containerized applications on multiple hosts in the cloud platform. The goal of Kubernetes is to make the deployment of containerized applications simple and efficient (powerful). Kubernetes provides application deployment, planning, update, and maintenance. a mechanism.

1. Machine preparation

The node diagram is as follows:

Target

• kubernetes version: 1.23.0
• Service can be deployed

Need to prepare 3 hosts, I am using 3 virtual machines, the configuration is as follows:

IP	Role	configure
192.168.67.101	k8s-master	2 core CPU, 2G memory
192.168.67.102	k8s-node1	1G memory
192.168.67.103	k8s-node2	1G memory

2. Environmental preparation

1. Modify hostname

# 方案1：
hostnamectl set-hostname <hostname>
# 例如
hostnamectl set-hostname k8s-master
hostnamectl set-hostname k8s-node1
hostnamectl set-hostname k8s-node2
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All machines below can be operated in batches

2. turn off firewall

# 临时关闭防火墙
systemctl stop firewalld
# 关闭开机自启动
systemctl disable firewalld
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3. close selinux

sed -i 's/enforcing/disabled/' /etc/selinux/config # 永久
setenforce 0 # 临时
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4. close swap

swapoff -a # 临时
sed -ri 's/.*swap.*/#&/' /etc/fstab #这样永久关闭
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5. add hosts

cat >> /etc/hosts << EOF
192.168.67.101 k8smaster
192.168.67.102 k8snode1
192.168.67.103 k8snode2
EOF
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6. Chain to pass bridged IPv4 traffic to iptables:

cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
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7. Change to Alibaba Cloud Mirror Source

#备份原来的镜像源
cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
#下载
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
# 重新建立缓存
yum makecache
# 查看仓库
yum repolist
# 安装必备软件（可选）
yum -y install lrzsz
yum -y install vim 
yum install -y wget
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8. time synchronization

yum install ntpdate -y
ntpdate time.windows.com
# 上面是windows的服务器，下方是中国服务器
ntpdate  cn.ntp.org.cn
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3. Install Docker/kubeadm/kubelet on all nodes

Kubernetes default CRI (container runtime) is Docker, so install Docker first.

Batch operation for all machines

1. Install 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-18.06.1.ce-3.el7
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2. Add Alibaba Cloud YUM software source, pay attention to the need to modify the cgroup of the docker container, kubelet recommends systemd

mkdir -p /etc/docker
tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://u4dk6b2s.mirror.aliyuncs.com"],
   "exec-opts": ["native.cgroupdriver=systemd"]
}
EOF
systemctl daemon-reload && systemctl restart docker
systemctl enable docker
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3. Add yum source for K8S

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
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4. Install kubeadm, kubelet and kubectl

yum install -y kubelet-1.23.0 kubeadm-1.23.0 kubectl-1.23.0
# 设置开机自启动
systemctl enable kubelet
#查看版本
kubelet --version
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4. Deploy the Master node

Execute at 192.168.67.101 ( Master ), note --apiserver-advertise-addressthat it needs to be the IP address of the master, the version number is 1.23.0, and other fields are ignored

kubeadm init \
--apiserver-advertise-address=192.168.67.101 \
--image-repository registry.aliyuncs.com/google_containers \
--kubernetes-version v1.23.0 \
--service-cidr=10.96.0.0/12 \
--pod-network-cidr=10.244.0.0/16
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After the installation is complete, you are prompted to execute the following statement, and you can execute it

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
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After the installation is complete, there are also the following command outputs that need to be executed, which are executed on the k8s-node1 node and k8s-node2 node respectively

kubeadm join 192.168.67.101:6443 --token qb4uwe.imwr6pkqy19vnjs1 \
	--discovery-token-ca-cert-hash sha256:caf1193372e07c2df962843cb8a87a62be7c3ee8cc2aa1fe5fbbc03bee8130c5 
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If the time is too long, the key may expire, or the log has not been flushed, you can use the following command to get the key

kubeadm token create --print-join-command
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Get node on master

[root@k8smaster ~]# kubectl get nodes
NAME        STATUS     ROLES                  AGE   VERSION
k8smaster   NotReady   control-plane,master   34m   v1.23.0
k8snode1    NotReady   <none>                 25s   v1.23.0
k8snode2    NotReady   <none>                 13s   v1.23.0
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Five, install the Pod network plug-in

Execute the following statement on the master node to download the network plug-in

# 不能访问github可以使用这个
kubectl apply -f https://rs.amoqi.cn/kube-flannel.yml
# github能访问使用这个
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
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You can use the following statement to monitor the mirror operation

kubectl get pods -w
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You can view the status of the node, it may take a while

[root@k8smaster ~]# kubectl get nodes
NAME        STATUS   ROLES                  AGE   VERSION
k8smaster   Ready    control-plane,master   55m   v1.23.0
k8snode1    Ready    <none>                 21m   v1.23.0
k8snode2    Ready    <none>                 21m   v1.23.0
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6. Service Test

Create a pod in the Kubernetes cluster and verify that it is running:

# 创建nginx容器
kubectl create deployment nginx --image=nginx
# 暴露nginx端口
kubectl expose deployment nginx --port=80 --type=NodePort
# 查看pod以及服务
[root@k8smaster ~]# kubectl get pod,svc
NAME                         READY   STATUS    RESTARTS   AGE
pod/nginx-85b98978db-lq8tn   1/1     Running   0          66s

NAME                 TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP        68m
service/nginx        NodePort    10.111.144.73   <none>        80:32076/TCP   5s
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