centos7.9安装k8s

说明：

本文档仅供学习参考使用

1.基础准备

1.1实验配置信息

具体配置信息根据需求设置

系统版本	主机名	配置	ip
centos7.9	master	2C+4G+30G	192.168.10.110
centos7.9	node1	2C+4G+30G	192.168.10.111
centos7.9	node2	2C+4G+30G	192.168.10.112

1.2 系统初始化设置

1.2.1 固定ip配置

[root@master ~]# vi /etc/sysconfig/network-scripts/ifcfg-ens33

1.2.2 设置主机名

#注意所有节点都设置，不能重名
[root@node2 ~]# hostnamectl set-hostname master

1.2.3 常用工具安装

yum install -y wget vim net-toos chrony

1.2.4 各节点时间同步设置

systemctl enable chronyd
systemctl restart chronyd 
systemctl status chronyd
chronyc sources -v

timedatectl set-timezone Asia/Shanghai
timedatectl status

date

1.2.5 禁用selinux

# 将 SELinux 设置为 permissive 模式（相当于将其禁用）

sudo setenforce 0
vim /etc/selinux/config
#永久关闭需将/etc/selinux/config 中的SELINUX的值改为disabled

1.2.6 关闭防火墙

systemctl stop firewalld
systemctl disable firewalld
systemctl status firewalld

1.2.7 关闭swap

swapoff -a  
sed -ri 's/.*swap.*/#&/' /etc/fstab
free

1.2.8 配置master的ssh免密登录

为了保险三台服务器都配上

echo "192.168.10.50  k8smaster" >> /etc/hosts
echo "192.168.10.51  node1" >> /etc/hosts
echo "192.168.10.52  node2" >> /etc/hosts

仅master节点操作

ssh-keygen -t rsa

ssh-copy-id node1

ssh-copy-id node2

1.2.9 配置iptables桥接功能及路由转发

sysctl -a |grep bridge  #过滤bridge不存在就用下面命令加载br_netfilter
modprobe br_netfilter

cat >> /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-iptables = 1
net.bridge.bridge-nf-call-ip6tables = 1
EOF

sysctl -p /etc/sysctl.d/k8s.conf

各节点开启转发

echo "net.ipv4.ip_forward = 1" >> /etc/sysctl.confsysctl -p

1.3 docker安装

1.3.1移除以前docker相关包

sudo yum remove docker \
                  docker-client \
                  docker-client-latest \
                  docker-common \
                  docker-latest \
                  docker-latest-logrotate \
                  docker-logrotate \
                  docker-engine

1.3.2 配置yum源

sudo yum install -y yum-utils
sudo yum-config-manager \
--add-repo \
http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

1.3.3 安装docker

sudo yum install -y yum-utils  device-mapper-persistent-data  lvm2
yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
sudo yum install -y docker-ce-19.03.13 docker-ce-cli-19.03.13 containerd.io-1.4.6
systemctl enable docker --now
docker version
ls
cd ~

1.3.4 配置加速

sudo mkdir -p /etc/docker
sudo tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://82m9ar63.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.k8s安装

2.1 k8s三大件安装

#（kubelet、kubeadm、kubectl）
#安装源信息写入文件

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=1
repo_gpgcheck=1
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
   http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
exclude=kubelet kubeadm kubectl
EOF



#下载三大件并安装


sudo yum install -y kubelet-1.20.9 kubeadm-1.20.9 kubectl-1.20.9 --disableexcludes=kubernetes

sudo systemctl enable --now kubelet

#查看状态，将停启循环
systemctl status kubelet

2.2 相关镜像获取

相关镜像信息写入文件并根据文件下载镜像

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 主节点初始化

#主节点初始化（注意自己的ip地址设置）#注意所有网络范围不重叠

kubeadm init \
--apiserver-advertise-address=192.168.10.50 \
--control-plane-endpoint=k8smaster \
--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=192.168.0.0/16

初始化成功

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 master:6443 --token hz33gv.8w7u29ncc0wwvcmv \
    --discovery-token-ca-cert-hash sha256:b41766710bdfd85da296d48c4f4b3fc3352d38de2b2f23b34d363d2ade9b14e3 \
    --control-plane 

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

kubeadm join master:6443 --token hz33gv.8w7u29ncc0wwvcmv \
    --discovery-token-ca-cert-hash sha256:b41766710bdfd85da296d48c4f4b3fc3352d38de2b2f23b34d363d2ade9b14e3 

执行启动kubectl命令

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

查看nodes节点与pod情况

kubectl get nodes
kubectl get pods -A

2.4 master节点加入

kubeadm join master:6443 --token hz33gv.8w7u29ncc0wwvcmv \
    --discovery-token-ca-cert-hash sha256:b41766710bdfd85da296d48c4f4b3fc3352d38de2b2f23b34d363d2ade9b14e3 \
    --control-plane

2.5 worker节点加入

#使用初始化成功后的提示信息在work节点上执行，注意只有两个小时的有效时间，
kubeadm join master:6443 --token hz33gv.8w7u29ncc0wwvcmv \
    --discovery-token-ca-cert-hash sha256:b41766710bdfd85da296d48c4f4b3fc3352d38de2b2f23b34d363d2ade9b14e3 
#如果过期了使用以下命令重新获取
kubeadm token create --print-join-command

#查看各个节点状态，都为NotReady是正常的，需要安装网络插件后才变为ready
[root@master ~]# kubectl get node
NAME     STATUS     ROLES                  AGE     VERSION
master   NotReady   control-plane,master   5h51m   v1.20.9
node1    NotReady   <none>                 15m     v1.20.9
node2    NotReady   <none>                 5h41m   v1.20.9

2.6 安装网络插件

网络插件有徐许多，如colico , kube-flannel.yml 等

#下载

curl https://docs.projectcalico.org/v3.18/manifests/calico.yaml -O
#
#安装

kubectl apply -f calico.yaml

#查看pod状态是否都启动为running状态

kubectl get pods -A 

#查看nodes状态是否为ready

kubectl get nodes

#如果还有异常，状态都为running，但ready为0的就重启下服务器
reboot

至此k8s安装成功

k8s常用命令

#命名空间的操作
kubectl get namespace

kubectl create ns test

kubectl delete ns test



#通过文件创建命名空间
#vim test.yml
apiVersion: v1
kind: Namespace
metadata:
  name: test1


#执行文件创建命名空间
kubectl apply -f test.yml

kubectl delete -f test.yml

kubectl run nginx --image=nginx:latest -n test1

kubectl get pod -n test1

kubectl describe pod nginx -n test1

kubectl logs -f nginx -n test1

#deployment相关
kubectl get deploy
kubectl get deploy -n test
#新增
kubectl create  deployment deploy-nginx --image=daocloud.io/library/nginx:1.9.1
#删除
kubectl delete deployment deploy-nginx
#对外暴露端口
kubectl expose deployment nginx-deployment --port=8888 --target-port=80 -n test1

kubectl get service -n test1

kubectl delete service nginx-deployment -n test1

kubectl expose deployment nginx-deployment --port=8888 --target-port=80 -n test1 --type=NodePort