10分钟搭建一个Kubernetes集群平台

官方提供3种方式部署Kubernetes

minikube

Minikube是一个工具，可以在本地快速运行一个单点的Kubernetes，尝试Kubernetes或日常开发的用户使用。不能用于生产环境。

官方文档：https://kubernetes.io/docs/setup/minikube/

kubeadm

kubeadm可帮助你快速部署一套kubernetes集群。kubeadm设计目的为新用户开始尝试kubernetes提供一种简单的方法。目前是Beta版。

官方文档：https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm/
https://kubernetes.io/docs/setup/independent/install-kubeadm/

二进制包

从官方下载发行版的二进制包，手动部署每个组件，组成Kubernetes集群。目前企业生产环境中主要使用该方式。
下载地址：https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.11.md#v1113

1. 安装要求

操作系统
Ubuntu 16.04+，Debian 9，CentOS 7，RHEL 7，Fedora 25/26 (best-effort)
内存2GB + ，2核CPU +
集群节点之间可以通信
每个节点唯一主机名，MAC地址和product_uuid

检查MAC地址：使用ip link或者ifconfig -a

检查product_uuid：cat /sys/class/dmi/id/product_uuid
禁止swap分区。这样才能使kubelet正常工作

2. 准备环境

关闭防火墙：
# systemctl stop firewalld
# systemctl disable firewalld

关闭selinux：
# sed -i 's/enforcing/disabled/' /etc/selinux/config 
# setenforce 0

关闭swap：
# swapoff -a  # 临时
# vim /etc/fstab  # 永久

添加主机名与IP对应关系：
# cat /etc/hosts
192.168.0.11 k8s-master
192.168.0.12 k8s-node1
192.168.0.13 k8s-node2

同步时间：
# yum install ntpdate -y
# ntpdate  ntp.api.bz

3. 安装Docker

Docker与Kubernetes关系图：

image

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

# yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

# yum install docker-ce-17.03.3.ce -y   #目前kubeadm最大支持docker-ce-17.03，所以要指定该版本安装

# systemctl enable docker && systemctl start docker

如果提示container-selinux依赖问题，先安装ce-17.03匹配版本：
# yum localinstall https://download.docker.com/linux/centos/7/x86_64/stable/Packages/docker-ce-selinux-17.03.3.ce-1.el7.noarch.rpm

4. 安装kubeadm，kubelet和kubectl

kubeadm：引导集群的命令
kubelet：集群中运行任务的代理程序
kubectl：命令行管理工具

4.1 添加阿里云YUM软件源

# 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=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

4.2 安装kubeadm，kubelet和kubectl

# yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes
# systemctl enable kubelet && systemctl start kubelet

注意：使用Docker时，kubeadm会自动检查kubelet的cgroup驱动程序，并/var/lib/kubelet/kubeadm-flags.env在运行时将其设置在文件中。如果使用的其他CRI，则必须在/etc/default/kubelet中cgroup-driver值修改为cgroupfs：

# cat /var/lib/kubelet/kubeadm-flags.env
KUBELET_KUBEADM_ARGS=--cgroup-driver=cgroupfs --cni-bin-dir=/opt/cni/bin --cni-conf-dir=/etc/cni/net.d --network-plugin=cni
# systemctl daemon-reload
# systemctl restart kubelet

5. 使用kubeadm创建单个Master集群

5.1 默认下载镜像地址在国外无法访问，先从准备好所需镜像

保存到脚本之间运行：

K8S_VERSION=v1.11.2
ETCD_VERSION=3.2.18
DASHBOARD_VERSION=v1.8.3
FLANNEL_VERSION=v0.10.0-amd64
DNS_VERSION=1.1.3
PAUSE_VERSION=3.1
# 基本组件
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver-amd64:$K8S_VERSION
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager-amd64:$K8S_VERSION
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler-amd64:$K8S_VERSION
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy-amd64:$K8S_VERSION
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/etcd-amd64:$ETCD_VERSION
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/pause:$PAUSE_VERSION
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:$DNS_VERSION
# 网络组件
docker pull quay.io/coreos/flannel:$FLANNEL_VERSION
# 修改tag
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver-amd64:$K8S_VERSION k8s.gcr.io/kube-apiserver-amd64:$K8S_VERSION
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager-amd64:$K8S_VERSION k8s.gcr.io/kube-controller-manager-amd64:$K8S_VERSION
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler-amd64:$K8S_VERSION k8s.gcr.io/kube-scheduler-amd64:$K8S_VERSION
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy-amd64:$K8S_VERSION k8s.gcr.io/kube-proxy-amd64:$K8S_VERSION
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/etcd-amd64:$ETCD_VERSION k8s.gcr.io/etcd-amd64:$ETCD_VERSION
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/pause:$PAUSE_VERSION k8s.gcr.io/pause:$PAUSE_VERSION
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:$DNS_VERSION k8s.gcr.io/coredns:$DNS_VERSION

5.2 初始化Master

# kubeadm init --kubernetes-version=1.11.2 --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=192.168.0.11

...

Your Kubernetes master has initialized successfully!

To start using your cluster, you need to run (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

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the addon options listed at:
  http://kubernetes.io/docs/admin/addons/

You can now join any number of machines by running the following on each node
as root:

  kubeadm join --token <token> <master-ip>:<master-port> --discovery-token-ca-cert-hash sha256:<hash>

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

5.3 安装Pod网络 - 插件

# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.yml

5.4 加入工作节点

在Node节点切换到root账号执行：

# kubeadm join 192.168.0.11:6443 --token 6hk68y.0rdz1wdjyh85ntkr --discovery-token-ca-cert-hash sha256:d1d3f59ae37fbd632707cbeb9b095d0d0b19af535078091993c4bc4d9d2a7782

6. kubernetes dashboard

先将yaml文件下载下来，修改里面镜像地址和Service NodePort类型。

# wget https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/recommended/kubernetes-dashboard.yaml

修改镜像地址：

# registry.cn-hangzhou.aliyuncs.com/google_containers/kubernetes-dashboard-amd64:v1.10.0

修改Service：

kind: Service
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kube-system
spec:
  type: NodePort
  ports:
    - port: 443
      targetPort: 8443
      nodePort: 30001
  selector:
    k8s-app: kubernetes-dashboard

# kubectl apply -f kubernetes-dashboard.yaml

创建一个管理员角色：

apiVersion: v1
kind: ServiceAccount
metadata:
  name: dashboard-admin
  namespace: kube-system
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: dashboard-admin
subjects:
  - kind: ServiceAccount
    name: dashboard-admin
    namespace: kube-system
roleRef:
  kind: ClusterRole
  name: cluster-admin
  apiGroup: rbac.authorization.k8s.io

# kubectl apply -f k8s-admin.yaml

使用上述创建账号的token登录Kubernetes Dashboard：

# kubectl get secret -n kube-system
# kubectl describe secret dashboard-admin-token-bwdjj  -n kube-system
...
token:      eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.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.0hQU5Di_P1OX1DcnW2AYzjDAED66EOrqhF5iupv39wvB8wE-aLRSQyp0twX2M8u1KMZ67n6LxbH17VwEQkMDRVXs7ZlUCyAAD6kHDz3k-f7PAzH5vcuyO4veQ9ooVjk3DKjrP4zXQChHllBB1wmD_oyLjoWxK3Z5MBTlVGzSixVwuQNpFPbuS6Z7iLGwUOgjI0cGZ9Tt6cXzcK81KfAEpDIP_CtFV_Jw4s98EgBex9mZh6vq1dcxr03qfuK--udd_8GWZctu_p_P15hZZLoKEm5GCbs6JGvKL2aao_DEHfLp3XYEnApojI91vU4qAqdkvMZ2qWQNGYv4KNi2yPOOJQ