Kubernetes结构图

kubeadm安装k8s

master & node

硬件配置

每个节点都要2核4G。

Linux配置

#各个机器设置自己的域名
hostnamectl set-hostname xxxx
# 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
#关闭swap
swapoff -a  
sed -ri 's/.*swap.*/#&/' /etc/fstab
#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

安装Docker

# 卸载已存在的docker
sudo yum remove docker \
                  docker-client \
                  docker-client-latest \
                  docker-common \
                  docker-latest \
                  docker-latest-logrotate \
                  docker-logrotate \
                  docker-engine
# 安装yum工具
yum install -y yum-utils
# 配置docker repo的国内地址
yum-config-manager \
    --add-repo \
    https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
# 刷新yum索引
yum makecache fast
# 安装docker相关的 docker-ce 社区版（ee是企业版，要收费）
yum install docker-ce docker-ce-cli containerd.io
# 启动docker
systemctl enable docker
systemctl start docker
# 使用docker version查看是否按照成功
[root@VM-8-9-centos ~]# docker version
Client: Docker Engine - Community
 Version:           20.10.9
 API version:       1.41
 Go version:        go1.16.8
 Git commit:        c2ea9bc
 Built:             Mon Oct  4 16:08:25 2021
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true
Server: Docker Engine - Community
 Engine:
  Version:          20.10.9
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.16.8
  Git commit:       79ea9d3
  Built:            Mon Oct  4 16:06:48 2021
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.4.11
  GitCommit:        5b46e404f6b9f661a205e28d59c982d3634148f8
 runc:
  Version:          1.0.2
  GitCommit:        v1.0.2-0-g52b36a2
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

下载可能用到的镜像

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

配置master节点域名

挑选一台机子作为master节点，其他机子作为node节点，查看master节点ip地址

将这个地址写入master节点和所有node节点的hosts。

echo "xx.xx.xx.xx  cluster-endpoint" >> /etc/hosts

安装kubelet、kubeadm、kubectl

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
exclude=kubelet kubeadm kubectl
EOF
sudo yum install -y kubelet-1.20.9 kubeadm-1.20.9 kubectl-1.20.9 --disableexcludes=kubernetes
sudo systemctl enable --now kubelet

master

安装控制平面

在master节点安装控制平面。安装的时候需要保证service-cidr、pod-network-cidr、docker0和eth0的网络范围不重叠。

kubeadm init \
--apiserver-advertise-address=`master 节点的IP` \
--control-plane-endpoint=cluster-endpoint \
--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

安装好之后会出现下面一段话。

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 cluster-endpoint:6443 --token hums8f.vyx71prsg74ofce7 \
    --discovery-token-ca-cert-hash sha256:a394d059dd51d68bb007a532a037d0a477131480ae95f75840c461e85e2c6ae3 \
    --control-plane 
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join cluster-endpoint:6443 --token hums8f.vyx71prsg74ofce7 \
    --discovery-token-ca-cert-hash sha256:a394d059dd51d68bb007a532a037d0a477131480ae95f75840c461e85e2c6ae3

按照上面的输出执行就行。

处理配置文件

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

安装网络组件

curl https://docs.projectcalico.org/manifests/calico.yaml -O
kubectl apply -f calico.yaml

node

加入集群

下面的命令是控制平面安装好之后输出的内容中最后一段后，给它拷贝到node节点执行即可。

kubeadm join cluster-endpoint:6443 --token hums8f.vyx71prsg74ofce7 \
    --discovery-token-ca-cert-hash sha256:a394d059dd51d68bb007a532a037d0a477131480ae95f75840c461e85e2c6ae3

获取token

安装控制平面之后输出的令牌，只在一段时间内有效，如果过了时间，node想加入集群，需要执行

[root@k8s-master ~]# kubeadm token create --print-join-command
kubeadm join cluster-endpoint:6443 --token 0d4c8q.tjsk2ge3u95070ll     --discovery-token-ca-cert-hash sha256:5f7659f39b097ed9312bb5b266d629551d93aaaa087c40076b9cba03988f50f9

查看集群状态

查询集群的节点

[root@k8s-master ~]# kubectl get nodes
NAME         STATUS   ROLES                  AGE   VERSION
k8s-master   Ready    control-plane,master   44h   v1.20.9
k8s-node1    Ready    <none>                 44h   v1.20.9
k8s-node2    Ready    <none>                 44h   v1.20.9

集群是否正常运行

[root@k8s-master ~]# kubectl get pods -A
NAMESPACE     NAME                                       READY   STATUS    RESTARTS   AGE
kube-system   calico-kube-controllers-659bd7879c-7r9cg   1/1     Running   2          44h
kube-system   calico-node-c5bcv                          1/1     Running   2          44h
kube-system   calico-node-plbqz                          1/1     Running   2          44h
kube-system   calico-node-v9lrm                          1/1     Running   2          44h
kube-system   coredns-5897cd56c4-lb5zl                   1/1     Running   2          44h
kube-system   coredns-5897cd56c4-x9sc9                   1/1     Running   2          44h
kube-system   etcd-k8s-master                            1/1     Running   2          44h
kube-system   kube-apiserver-k8s-master                  1/1     Running   3          44h
kube-system   kube-controller-manager-k8s-master         1/1     Running   2          44h
kube-system   kube-proxy-58mnj                           1/1     Running   2          44h
kube-system   kube-proxy-9wxjw                           1/1     Running   2          44h
kube-system   kube-proxy-jzv5s                           1/1     Running   2          44h
kube-system   kube-scheduler-k8s-master                  1/1     Running   2          44h

当我们新创建一个集群之后，如果上面获取集群所有pod的命令输出的结果是所有的pod都READY 1/1，就说明这个集群正常运行了。

1、Kubernetes安装