kubeadmin 快速部署k8s集群

安装要求

在开始之前，部署Kubernetes集群机器需要满足以下几个条件：

• 一台或多台机器，操作系统 CentOS7.x-86_x64
• 硬件配置：2GB或更多RAM，2个CPU或更多CPU，硬盘30GB或更多
• 集群中所有机器之间网络互通
• 可以访问外网，需要拉取镜像
• 禁止swap分区

学习目标

1. 在所有节点上安装Docker和kubeadm
2. 部署Kubernetes Master
3. 部署容器网络插件
4. 部署 Kubernetes Node，将节点加入Kubernetes集群中
5. 部署Dashboard Web页面，可视化查看Kubernetes资源

准备环境

关闭防火墙：
$ systemctl stop firewalld
$ systemctl disable firewalld
$ iptables -F

关闭selinux：
$ sed -i "s/^SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config
$ sed -i "s/^SELINUX=permissive/SELINUX=disabled/g" /etc/selinux/config
$ setenforce 0
$ cat /etc/selinux/config

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing - SELinux security policy is enforced.
#     permissive - SELinux prints warnings instead of enforcing.
#     disabled - No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of three two values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected.
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted

关闭swap：
$ swapoff -a $ 临时
$ vim /etc/fstab $ 永久
$ sed -i 's/.*swap.*/#&/' /etc/fstab
cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Mon Mar  4 17:23:04 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root /                       xfs     defaults        0 0
UUID=3dd5660e-0905-4f1e-9fa3-9ce664d6eb94 /boot                   xfs     defaults        0 0
/dev/mapper/centos-home /home                   xfs     defaults        0 0
#/dev/mapper/centos-swap swap                    swap    defaults        0 0


将桥接的IPv4流量传递到iptables的链：
$ cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
$ sysctl --system
修改文件句柄限制
echo "* soft nofile 65536" >> /etc/security/limits.conf
echo "* hard nofile 65536" >> /etc/security/limits.conf
echo "* soft nproc 65536"  >> /etc/security/limits.conf
echo "* hard nproc 65536"  >> /etc/security/limits.conf
echo "* soft  memlock  unlimited"  >> /etc/security/limits.conf
echo "* hard memlock  unlimited"  >> /etc/security/limits.conf

所有节点安装Docker/kubeadm/kubelet

Kubernetes默认CRI（容器运行时）为Docker，因此先安装Docker。

安装Docker

$ wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
$ yum -y install docker-ce-18.06.1.ce-3.el7
$ systemctl enable docker && systemctl start docker
$ docker --version
Docker version 18.06.1-ce, build e68fc7a

添加阿里云YUM软件源

$ cat > /etc/yum.repos.d/kubernetes.repo << EOF
[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

导入gpgkey文件
$ wget https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
$ rpm --import yum-key.gpg
$ wget https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
$ rpm --import rpm-package-key.gpg

安装kubeadm，kubelet和kubectl

由于版本更新频繁，这里指定版本号部署：

$ yum install -y kubelet-1.13.3 kubeadm-1.13.3 kubectl-1.13.3 kubernetes-cni-0.6.0
$ systemctl enable kubelet

部署Kubernetes Master

由于默认拉取镜像地址k8s.gcr.io国内无法访问，这里指定阿里云镜像仓库地址。

$ kubeadm init \
--apiserver-advertise-address=10.0.52.13 \
--image-repository registry.aliyuncs.com/google_containers \
--kubernetes-version v1.13.3 \
--service-cidr=10.1.0.0/16 \
--pod-network-cidr=10.244.0.0/16

使用kubectl工具：

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

安装Pod网络插件（CNI）

$ kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/a70459be0084506e4ec919aa1c114638878db11b/Documentation/kube-flannel.yml

确保能够访问到quay.io这个registery。

加入Kubernetes Node

向集群添加新节点，执行在kubeadm init输出的kubeadm join命令：

kubeadm join 10.0.52.13:6443 --token nqg5gl.zr84xb63z2ve7dbn --discovery-token-ca-cert-hash sha256:3e43b9c41dd74ba0f46c260d0e0b6663993cf4563c3852384916d76338d6202e

在master执行

$ kubectl get nodes

测试kubernetes集群

在Kubernetes集群中创建一个pod，验证是否正常运行：

$ kubectl create deployment nginx --image=nginx
$ kubectl expose deployment nginx --port=80 --type=NodePort
$ kubectl get pod,svc

访问地址：http://NodeIP:Port

部署 Dashboard

kubectl apply -f kubernetes-dashboard.yaml

kubectl apply -f admin-dashboard.yaml

访问地址：http://NodeIP:30001

选择令牌,令牌获取如下:

kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}')

首页如下: