CentOS 8.1安装Kubernetes 1.18.2

前提：

1、操作系统Centos 8
2、通过阿里云相关镜像源安装

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以下均为root用户下操作

操作步骤：

1、修改主机名

hostnamectl set-hostname hanyu

2、关闭防火墙

systemctl stop firewalld.service
systemctl disable firewalld.service

3、安装docker

安装必要的工具

yum install -y yum-utils device-mapper-persistent-data lvm2

配置官方docker源或者aliyun docker源

yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
或者
yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

查询docker版本（否则yum install默认安装最新的版本）

yum list docker-ce --showduplicates | sort -r

安装指定版本docker

yum -y install docker-ce-18.09.3-3.el7

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解决方法：
wget https://download.docker.com/linux/centos/7/x86_64/edge/Packages/containerd.io-1.2.6-3.3.el7.x86_64.rpm
yum install -y containerd.io-1.2.6-3.3.el7.x86_64.rpm

启动docker

systemctl enable docker && systemctl start docker

查询docker服务状态

systemctl status docker

查看docker版本

docker version

4、安装kubelet、kubeadm 和 kubectl

配置kubernetes.repo的源，由于官方源国内无法访问，这里使用阿里云yum源

[root@hanyu1 ~]# cat < /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

在所有节点上安装指定版本 kubelet、kubeadm 和 kubectl

yum list kubectl --showduplicates | sort -r
yum list kubeadm --showduplicates | sort -r
yum list kubelet --showduplicates | sort -r
yum install -y kubectl-1.18.2.-0 kubeadm-1.18.2-0 kubelet-1.18.2-0

启动kubelet服务

systemctl enable kubelet && systemctl start kubelet

5、关闭swap分区

swapoff -a

6、初始化master节点

kubeadm init --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.18.2 --pod-network-cidr=10.244.0.0/16 --token-ttl 0 --ignore-preflight-errors=Swap

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按照kubeadm init成功后打印提示，继续操作：

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

kubectl get nodes查询到节点处于NotReady状态，是因为网络插件还未就位，也就是这里要求运行的

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/

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如果要暂时忽略让节点Ready，将如下文件的--network-plugin=cni字段去掉, (该文件是在kubeadm init或者kubeadm join过程中生成的), 修改完后重启kubelet即可(systemctl restart kubelet)

[root@hanyu ~]# cat /var/lib/kubelet/kubeadm-flags.env
KUBELET_KUBEADM_ARGS="--cgroup-driver=cgroupfs --network-plugin=cni --pod-infra-container-image=registry.aliyuncs.com/google_containers/pause:3.2"

此处安装flannel后，node ready

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7、join node节点

[root@hanyu2 ~]# kubeadm join 10.0.104.125:6443 --token 9o697n.syq87aguxtdmcn76 --discovery-token-ca-cert-hash sha256:294e07d4f7f09e4c99ef96a8563546e002672b8535ee7bc339e423d5cf38aa4c
[preflight] Running pre-flight checks
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.16" ConfigMap in the kube-system namespace
[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] Activating the kubelet service
[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.

查询所有node及pod状态

kubectl get node -o wid
kubectl get pod --all-namespaces -o wide

增加kubectl命令自动补全功能

source <(kubectl completion bash)

默认master节点不会调度pod，去掉此限制

kubectl taint node hostname node-role.kubernetes.io/master:NoSchedule-