k8s集群1.20.9

一.k8s安装

搭建K8S集群，准备三台2核4G的虚拟机(内存至少2G以上)，操作系统选择用centos 7以上版本

主机	说明
192.168.33.35	k8s-master
192.168.33.190	k8s-node1

1、安装Docker

sudo yum remove docker*

sudo yum install -y yum-utils

#配置docker的yum地址
sudo yum-config-manager \
--add-repo \
http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo


#安装指定版本
sudo yum install -y docker-ce-20.10.7 docker-ce-cli-20.10.7 containerd.io-1.4.6

#启动&开机启动docker
systemctl enable docker --now

# docker镜像加速器配置
sudo mkdir -p /etc/docker
sudo tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://jbw52uwf.mirror.aliyuncs.com"],
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2"
}
EOF
sudo systemctl daemon-reload
sudo systemctl restart docker

2、安装Kubernetes

2.1 基本环境

所有机器执行以下操作

每个机器使用内网ip互通

#1. 关闭防火墙并设置开机不启动
systemctl stop firewalld
systemctl disable firewalld

# 2、关闭 selinux
# 将 SELinux 设置为 permissive 模式（相当于将其禁用）
sudo setenforce 0
sudo sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

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

systemctl reboot  #重启生效
free -m  #查看下swap交换区是否都为0，如果都为0则swap关闭成功

#4、给三台机器分别设置主机名
hostnamectl set-hostname k8s-master
hostnamectl set-hostname k8s-node1
第一台：k8s-master
第二台：k8s-node1


#5、添加hosts，执行如下命令，ip需要修改成你自己机器的ip
cat >> /etc/hosts << EOF
192.168.33.35 k8s-master
192.168.33.190 k8s-node1
EOF


#6、允许 iptables 检查桥接流量
cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
br_netfilter
EOF

cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sudo sysctl --system  

#7、设置时间同步
yum install ntpdate -y
ntpdate time.windows.com

2.2 安装kubelet、kubeadm、kubectl

#8、配置k8s的yum源地址
cat <<EOF | sudo tee /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
   http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

#9、如果之前安装过k8s，先卸载旧版本
yum remove -y kubelet kubeadm kubectl

#10、查看可以安装的版本
yum list kubelet --showduplicates | sort -r

#11、安装 kubelet，kubeadm，kubectl指定版本，我们使用kubeadm方式安装k8s集群
sudo yum install -y kubelet-1.20.9 kubeadm-1.20.9 kubectl-1.20.9

#12、开机启动kubelet
sudo systemctl enable --now kubelet

2.3 初始化master节点

2.3.1 下载各个机器需要的镜像

sudo tee ./images.sh <<-'EOF'
#!/bin/bash
images=(
kube-apiserver:v1.20.9
kube-proxy:v1.20.9
kube-controller-manager:v1.20.9
kube-scheduler:v1.20.9
coredns:1.7.0
etcd:3.4.13-0
pause:3.2
)
for imageName in ${images[@]} ; do
docker pull registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images/$imageName
done
EOF
   
chmod +x ./images.sh && ./images.sh

2.3.2 初始化主节点

# 在k8s-master机器上执行初始化操作(里面的第一个ip地址就是k8s-master机器的ip，改成你自己机器的，后面两个ip网段不用动)
#所有网络范围不重叠
kubeadm init \
--apiserver-advertise-address=192.168.33.35 \
--control-plane-endpoint=k8s-master \
--image-repository registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images \
--kubernetes-version v1.20.9 \
--service-cidr=10.96.0.0/16 \
--pod-network-cidr=10.244.0.0/16


# 可以查看kubelet日志
journalctl -xefu kubelet  



#如果初始化失败，重置kubeadm
kubeadm reset

rm -rf /etc/cni/net.d  $HOME/.kube/config
#清理 iptables 规则
iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -t mangle -F
iptables -t mangle -X
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT

2.3.3 根据提示继续

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/

You can now join any number of control-plane nodes by copying certificate authorities
and service account keys on each node and then running the following as root:

  kubeadm join k8s-master:6443 --token 50rexj.yb0ys92ynnxxbo2s \
    --discovery-token-ca-cert-hash sha256:10fd9d2a9f4e2d7dff502aa3fb31a80f0372666efc92defde3707b499ba000e9 \
    --control-plane 

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

kubeadm join k8s-master:6443 --token 50rexj.yb0ys92ynnxxbo2s \
    --discovery-token-ca-cert-hash sha256:10fd9d2a9f4e2d7dff502aa3fb31a80f0372666efc92defde3707b499ba000e9

设置.kube/config

# 配置使用 kubectl 命令工具
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

export KUBECONFIG=/etc/kubernetes/admin.conf
echo $KUBECONFIG

安装Calico网络插件

curl https://docs.projectcalico.org/archive/v3.20/manifests/calico.yaml -O

kubectl apply -f calico.yaml

如果配置多网卡，出现下面的错误：calico/node is not ready: BIRD is not ready: BGP not established with xxx

修改calico.yaml的内容,指定网卡，添加下面两行：

- name: IP_AUTODETECTION_METHOD
  value: "interface=ens33"

2.3.4 加入node节点

可以通过下面的命令重新生成令牌

kubeadm token create --print-join-command

# 将node节点加入进master节点的集群里
kubeadm join k8s-master:6443 --token 50rexj.yb0ys92ynnxxbo2s \
    --discovery-token-ca-cert-hash sha256:10fd9d2a9f4e2d7dff502aa3fb31a80f0372666efc92defde3707b499ba000e9

# node节点执行kubectl命令kubectl get nodes出现下面的错误：
The connection to the server localhost:8080 was refused - did you specify the right host or port?
# 解决方案： 在node节点配置KUBECONFIG环境变量即可
echo "export KUBECONFIG=/etc/kubernetes/kubelet.conf" >> /etc/profile
source /etc/profile

2.3.5 验证集群节点状态

[root@192 kubernetes]# kubectl get nodes
NAME         STATUS   ROLES                  AGE   VERSION
k8s-master   Ready    control-plane,master   44m   v1.20.9
k8s-node1    Ready    <none>                 10m   v1.20.9

修改节点角色 ：kubectl label node k8s-node1  node-role.kubernetes.io/worker=worker