kubeadm安装Kubernetes单节点master集群

环境准备

1. Harbor（docker仓库,不介绍安装过程）
2. k8s-master
3. k8s-node01
4. k8s-node02

安装准备 (master & node)

//安装依赖包  
yum install -y conntrack ntpdate ntp ipvsadm ipset jq libseccomp -y
//设置防火墙为iptables并设置空规则  
systemctl stop firewalld && systemctl disable firewalld
yum install -y iptables-services && systemctl start iptables && systemctl enable iptables && iptables -F && service iptables save
//关闭swap
swapoff -a
sed -i '/swap/d' /etc/fstab
//调整内核参数，对于K8s
cat > /etc/sysctl.d/kubernetes.conf <<EOF
net.bridge.bridge-nf-call-iptables=1
net.bridge.bridge-nf-call-ip6tables=1
net.ipv4.ip_forward=1
vm.swappiness=0
net.netfilter.nf_conntrack_max=2310720
EOF
sysctl -p /etc/sysctl.d/kubernetes.conf

//升级系统内核4.44，提升k8s稳定性（3.x内核也可以，但不建议，对k8s支持不是特别好，有bug）
rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm  
//安装完成后检查/boot/grub2/grub.cfg中对对应内核中是否包含initrd16配置，如没有再次安装
yum --enablerepo=elrepo-kernel install -y kernel-lt
//设置开机从新内核启动（根据具体的安装内核版本号修改）
grub2-set-default "CentOS Linux (4.4.186-1.el7.elrepo.x86_64) 7 (Core)"  
//重启
reboot

kuber_proxy开启的前置条件(master & node)

modprobe br_netfilter
cat > /etc/sysconfig/modules/ipvs.nodules << EOF
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
EOF
chmod 755 /etc/sysconfig/modules/ipvs.nodules
/etc/sysconfig/modules/ipvs.nodules && lsmod|grep -e ip_vs -e nf_conntrack_ipv4

安装docker

yum install -y yum-utils device-mapper-persistent-data lvm2 -y
yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -y
yum update -y
yum install docker-ce -y 
systemctl enable docker
systemctl start docker

安装kubeadm(master & node)

cat > /etc/yum.repos.d/kubernetes.repo << EOF
[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
yum install -y kubeadm-1.15.1 kubectl-1.15.1 kubelet-1.15.1
systemctl enable kubelet.service

安装kubernetes

1. 初始化主节点安装用配置文件

//生成默认初始化配置文件
kubeadm config print init-defaults >kubeadm.yaml
//修改生成的配置文件
advertiseAddress: 192.168.1.2       //主节点IP地址
kubernetesVersion: v1.15.1          //安装的版本
imageRepository: registry.aliyuncs.com/google_containers  //修改安装源为阿里云镜像
networking:
  podSubnet: "10.244.0.0/16"     //增加一行设置pod分配的网段信息
//在最后添加下列信息，将默认的调度方式改为IPVS
---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
featureGates:
  SupportIPVSProxyMode: true
mode: ipvs

2. 下载安装kubernetes images(master & node)

cat > k8s-images.sh << EOF
#!/bin/bash
# download k8s 1.15.1 images
# get image-list by 'kubeadm config images list --kubernetes-version=v1.15.1'

images=(
kube-apiserver:v1.15.1
kube-controller-manager:v1.15.1
kube-scheduler:v1.15.1
kube-proxy:v1.15.1
pause:3.1
etcd:3.3.10
coredns:1.3.1
)

for imageName in ${images[@]};do
	docker pull registry.aliyuncs.com/google_containers/$imageName
done
EOF

sh k8s-images.sh

3. 安装kubernetes

//方法（使用kubeadm生成的配置文件）
kubeadm init --config kubeadm.yaml  --upload-certs |tee kubeadmin-init.log

//安装完成后，根据提示，必须执行以下操作
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config

Flannel网路部署

wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
//kube-flannel中Pod网段必须和kubernetes中配置的Pod网段一致
//kube-flannel默认Pod的网段为10.244.0.0/16
kubectl create -f kube-flannel.yml

查看kubernetes信息

//查看所有kubernetes组件信息
kubectl get pod -n kube-system
//查看k8s master信息
kubectl get node

node节点部署

node安装kubelet/kubeadm

[root@k8s-node01 ~]# cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=0
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
[root@k8s-node01 ~]# yum install kubeadm kubelet -y
[root@k8s-node01 ~]# systemctl enable kubelet

将node节点加入到k8s集群中

 通过使用kubeadm join命令将node节点加入到集群中，具体加入命令可以在k8s master安装完成后的日志末尾查看。记录加入集群的令牌  每个需要加入的节点都需要运行

//如下所示：
kubeadm join 192.168.1.2:6443 --token abcdef.0123456789abcdef 
--discovery-token-ca-cert-hash sha256.........

//node节点执行加入命令
[root@k8s-node01 ~]# kubeadm join 192.168.1.2:6443 --token nag8y9.9vllybijsnn7xrzd 
    --discovery-token-ca-cert-hash sha256:0f8e9cec4c19ca004fd7c9a906691e5295dd5e38e5265e0edcba0b06cc2a7e14

在master上执行验证节点是否加入集群

[root@k8s-master ~]# kubectl get nodes
NAME     STATUS     ROLES    AGE     VERSION
master   Ready      master   72m     v1.15.0
node01   Ready      <none>   5m33s   v1.15.0
node02   NotReady   <none>   14s     v1.15.0