手把手教你用 kubeadm 安装 k8s v1.20

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kubeadmin 安装 k8s v1.20

一、环境准备

kubernetes.jpg

PS:本次实验采用单 mster 节点,两个 worker 节点组成 kubernetes 集群,版本是 v1.20.9。由于是笔记本自建虚拟机,所以配置相对低一些,有条件的同学可以适当调高配置

操作系统 角色 硬盘 CPU & MEM
Centos 7.9 master 40GB 4 核 8G
Centos 7.9 node01 40GB 2 核 4G
Centos 7.9 node02 40GB 2 核 4G

二、安装容器运行时---Docker

2.1、添加阿里镜像源

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

2.2、安装 docker

yum install -y docker-ce-20.10.7 docker-ce-cli-20.10.7 containerd.io-1.4.6

2.3、启动

systemctl enable docker --now

2.4、配置加速

这里额外添加了 docker 的生产环境核心配置 cgroup

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

三、安装 kubernetes

3.1、基础环境

所有机器执行以下操作

#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

3.2、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

kubelet 现在每隔几秒就会重启,因为它陷入了一个等待 kubeadm 指令的死循环

3.3、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

3.4、配置 hosts 解析

echo -e "192.168.1.10 master \n192.168.1.11 node01\n192.168.1.12 node02" >> /etc/hosts

3.5、master 节点初始化集群

注意:
1. 所有网络范围不重叠
2. advertise-address 等于 master 的 IP
3. plane-endpoint 等于填写在 hosts 文件中的 master

kubeadm init \ --apiserver-advertise-address=192.168.1.10 \ --control-plane-endpoint=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=10.168.0.0/16

初始化成功
提示信息保存一下,以后加入主节点或 worker 节点使用

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 4qw94d.i5fa5tgtztd5o5nu \ --discovery-token-ca-cert-hash sha256:ec7c8b230762c533c055493a4e4c210e7a5587a8b153cf38da7d5e2bbeb621c6 \ --control-plane Then you can join any number of worker nodes by running the following on each as root: kubeadm join master:6443 --token 4qw94d.i5fa5tgtztd5o5nu \ --discovery-token-ca-cert-hash sha256:ec7c8b230762c533c055493a4e4c210e7a5587a8b153cf38da7d5e2bbeb621c6

3.6、执行初始化命令

仅在 master 节点执行如下命令

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

3.7、加入剩余两个 worker 节点

两个 worker 节点分别执行如下命令(在上面有)

kubeadm join master:6443 --token 4qw94d.i5fa5tgtztd5o5nu \ > --discovery-token-ca-cert-hash sha256:ec7c8b230762c533c055493a4e4c210e7a5587a8b153cf38da7d5e2bbeb621c6 [preflight] Running pre-flight checks [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 20.10.7. Latest validated version: 19.03 [preflight] Reading configuration from the cluster... [preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml' [kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml" [kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env" [kubelet-start] Starting the kubelet [kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap... This node has joined the cluster: * Certificate signing request was sent to apiserver and a response was received. * The Kubelet was informed of the new secure connection details. Run 'kubectl get nodes' on the control-plane to see this node join the cluster.

3.8、验证

可以看到我们的集群已经搭建完成,但是节点都是 Notready,是因为 k8s 各节点通信通过第三方的网络插件,所以接下来我们需要安装第三方网络插件

[root@master ~]# kubectl get node NAME STATUS ROLES AGE VERSION master NotReady control-plane,master 7m51s v1.20.9 node01 NotReady <none> 2m3s v1.20.9 node02 NotReady <none> 2m v1.20.9

四、安装 calico 网络组件

4.1、下载 calico 的配置文件

yum isntall -y wget && wget https://docs.projectcalico.org/manifests/calico.yaml --no-check-certificate

4.2、修改配置文件

注意:
calico 默认的 CALICO_IPV4POOL_CIDR 是 192.168.0.0/16,在上面 3.5、master 节点初始化集群步骤中,为避免网段重复。所以更改了 CIDR 的值,所以在 calico 的配置文件中,要修改成相同的值,并取消注释
如下图:
在这里插入图片描述

4.3、通过命令安装 calico 网络插件

kubectl create -f calico.yaml ##等待4-5分钟 kubectl get pod -n kube-system NAME READY STATUS RESTARTS AGE calico-kube-controllers-659bd7879c-jndd7 1/1 Running 0 8m20s calico-node-f7jbc 1/1 Running 0 8m20s calico-node-x64f6 1/1 Running 0 8m20s calico-node-zcxl2 1/1 Running 0 8m20s coredns-5897cd56c4-js7h4 1/1 Running 0 37m coredns-5897cd56c4-t46w8 1/1 Running 0 37m etcd-master 1/1 Running 0 37m kube-apiserver-master 1/1 Running 0 37m kube-controller-manager-master 1/1 Running 0 37m kube-proxy-4tmqd 1/1 Running 0 31m kube-proxy-d5sxh 1/1 Running 0 37m kube-proxy-hh6fv 1/1 Running 0 31m kube-scheduler-master 1/1 Running 0 37m

当我们看到都是 Running 的时候,就代表我们 calico 网络插件安装成功了,
此时我们去看一下 node 的状态,发现已经全部 ready 了,至此 kubernetes 安装成功

[root@master ~]# kubectl get node NAME STATUS ROLES AGE VERSION master Ready control-plane,master 39m v1.20.9 node01 Ready <none> 33m v1.20.9 node02 Ready <none> 33m v1.20.9
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