对于刚接触到k8s的同学来说可能有熟悉过其基本概念,但是总在安装集群这里卡壳,我写这篇文章的目的是快速的构建一个试验可用的k8s单主集群,并不针对生产; 文章中尽可能详细的向同学们描述安装的过程; 该集群构建在阿里云ECS中,不具备条件的同学可使用虚拟机; 步骤及设置规则基本相同; 特殊之处会有详细的说明;

环境说明

所有节点系统层面准备工作

# 开启路由转发功能及网桥设置
$ vim /etc/sysctl.conf
net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
$ sysctl -p

# 加载内核lvs相关内核模块
$ cat >/etc/sysconfig/modules/ipvs.modules<<EOF
#!/bin/bash
modprobe br_netfilter
modprobe ip_vs
modprobe ip_vs_rr
modprobe ip_vs_wrr
modprobe ip_vs_sh
modprobe nf_conntrack_ipv4
EOF
$ chmod +x /etc/sysconfig/modules/ipvs.modules
$ source /etc/sysconfig/modules/ipvs.modules

所有节点安装docker及kubeadm相关软件

# step 1: 安装必要的一些系统工具
$ yum install -y yum-utils device-mapper-persistent-data lvm2

# Step 2: 添加软件源信息
$ yum-config-manager --add-repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

# Step 3: 更新并安装Docker-CE
$ yum makecache fast
$ yum -y install docker-ce

# Step 4: 开启Docker服务
$ service docker start
$ chkconfig docker on

# Step 5: 开启docker镜像加速
$ tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://aoewjvel.mirror.aliyuncs.com"],
  "exec-opts": ["native.cgroupdriver=systemd"]
}
EOF
$ systemctl daemon-reload && systemctl restart docker

# Step 6: 安装kubeadm工具
$ 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
EOF
$ yum install -y kubelet kubeadm kubectl
$ systemctl enable kubelet && systemctl start kubelet

注意: 根据官方说明, 在未初始化之前kubelet是无限重启的状态,只有初始化后才会真的存活于启动状态; 所以kubelet未启动先不用管!

Master节点: 使用kubeadm初始化

$ kubeadm config print init-defaults >> kubeinit.yml
$ vim kubeinit.yml
localAPIEndpoint:
  advertiseAddress: 172.26.61.54    # 本地IP地址
  bindPort: 6443
......
......
imageRepository: registry.aliyuncs.com/google_containers    # 修改为国内镜像
kind: ClusterConfiguration
kubernetesVersion: v1.17.0      # 可调整安装的版本
networking:
  dnsDomain: cluster.local
  serviceSubnet: 10.96.0.0/12
  podSubnet: 10.244.0.0/16      # 增加pod的节点ip范围
......
......

# 根据配置文件下载所需镜像
$ kubeadm config images pull --config=kubeinit/kubeinit.yml

# 使用配置文件进行初始化(要注意保留token字段值, 待会node加入节点要用到)
$ kubeadm init --config=kubeinit/kubeinit.yml

# 根据初始化后的输出进行的设置
$ mkdir -p $HOME/.kube
$ cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
$ chown $(id -u):$(id -g) $HOME/.kube/config

# 安装flannel网络插件(加载的时间可能会较长,耐心等待即可)
$ kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

# 最后查看所有组件的运行状态
$ kubectl get nodes --all-namespaces
NAMESPACE     NAME                                 READY   STATUS    RESTARTS   AGE
kube-system   coredns-9d85f5447-4g25h              1/1     Running   0          41m
kube-system   coredns-9d85f5447-5xggq              1/1     Running   0          41m
kube-system   etcd-kubemaster                      1/1     Running   0          42m
kube-system   kube-apiserver-kubemaster            1/1     Running   0          42m
kube-system   kube-controller-manager-kubemaster   1/1     Running   0          42m
kube-system   kube-flannel-ds-amd64-7bqgb          1/1     Running   0          39m
kube-system   kube-flannel-ds-amd64-b2ps4          1/1     Running   0          17m
kube-system   kube-proxy-946mp                     1/1     Running   0          17m
kube-system   kube-proxy-b7mmc                     1/1     Running   0          41m
kube-system   kube-scheduler-kubemaster            1/1     Running   0          42m

Node节点: 加入集群 kubeadm join

$ vim joinmaster.yml:

apiVersion: kubeadm.k8s.io/v1beta1
kind: JoinConfiguration
discovery:
  bootstraToken:
    apiServerEndpoint: 172.26.61.54:6443
    token: abcdef.0123456789abcdef    #这就是刚刚保存的token
    unsafeSkipCAVerification: true
  tlsBootstrapToken: abcdef.0123456789abcdef

$ kubeadm join --config=joinmaster.yml

最后查看集群的运行状态

$ kubectl get nodes
NAME         STATUS   ROLES    AGE   VERSION
kubemaster   Ready    master   16h   v1.17.3
kubenode     Ready    <none>   16h   v1.17.3

至此集群的安装已经完毕! 下面我们来配置dashboard!

Master节点: 配置Dashboard

# 使用 wget下载dashboard的配置文件到本地更改如下字段
$ wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0-rc5/aio/deploy/recommended.yaml

$ vim recommended.yaml
kind: Service
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kubernetes-dashboard
spec:
  type: NodePort          # 使用nodePort方式把pod的端口映射到节点上
  ports:
    - port: 443
      targetPort: 8443
      nodePort: 30443     # 节点端口
  selector:
    k8s-app: kubernetes-dashboard

# 构建dashboard
$ kubectl apply -f recommended.yaml

# 查看dashboard启动情况
$ kubectl get pods --all-namespaces
......
kubernetes-dashboard   dashboard-metrics-scraper-7b8b58dc8b-n6x77   1/1     Running   0          90s
kubernetes-dashboard   kubernetes-dashboard-866f987876-zr9zf        1/1     Running   0          90s

注意: 确定dashboard为Running状态后,使用火狐浏览器访问时会拒绝连接, 原因是不安全, 我们点击继续访问即可

生成访问用户

$ vim dashboard_config.yml

apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin-user
  namespace: kube-system


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

$ kubectl apply -f dashboard_config.yml

# 获取用户的token用于登录
$ kubectl -n kube-system describe secret admin-user-token-n8w8l
# 将输出的token复制到浏览器中即可访问dashboard了