Kubeadm搭建K8s集群

准备

准备三台服务器。云服务器或者本地vagrant+VirtualBOX创建虚拟机都行。

三个节点安装’docker’,‘kubeadm’, ‘kubelet’ and ‘kubectl’

vi etc/yum.repos.d/kubernetes.repo
添加如下内容
[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

安装
yum install -y kubectl kubelet kubeadm
开机启动
systemctl enable kubelet
启动
systemctl start kubelet

[[email protected] ~]$ which kubeadm
/usr/bin/kubeadm
[[email protected] ~]$ which kubelet
/usr/bin/kubelet
[[email protected] ~]$ which kubectl
/usr/bin/kubectl
[[email protected] ~]$ sudo docker version
Client:
 Version:         1.13.1
 API version:     1.26
 Package version: docker-1.13.1-63.git94f4240.el7.centos.x86_64
 Go version:      go1.9.4
 Git commit:      94f4240/1.13.1
 Built:           Fri May 18 15:44:33 2018
 OS/Arch:         linux/amd64

Server:
 Version:         1.13.1
 API version:     1.26 (minimum version 1.12)
 Package version: docker-1.13.1-63.git94f4240.el7.centos.x86_64
 Go version:      go1.9.4
 Git commit:      94f4240/1.13.1
 Built:           Fri May 18 15:44:33 2018
 OS/Arch:         linux/amd64
 Experimental:    false
[[email protected] ~]$

---

初始化 master node

[[email protected] ~]$ sudo kubeadm init --pod-network-cidr 172.100.0.0/16 --apiserver-advertise-address 192.168.205.120
看到下面信息就表示成功了
......
Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 192.168.205.120:6443 --token snipoh.vxfykjsi7e7rbtna \
    --discovery-token-ca-cert-hash sha256:e202fbfa3eed1e1d6c646dd568285947d67e99b51e824c99aeb6f45080d284c1
[[email protected] ~]$

然后在master节点上运行

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

检查pod

[[email protected] ~]$ kubectl get pod --all-namespaces
NAMESPACE     NAME                                 READY   STATUS    RESTARTS   AGE
kube-system   coredns-5c98db65d4-f4kjf             0/1     Pending   0          58m
kube-system   coredns-5c98db65d4-xqpwd             0/1     Pending   0          58m
kube-system   etcd-k8s-master                      1/1     Running   0          57m
kube-system   kube-apiserver-k8s-master            1/1     Running   0          57m
kube-system   kube-controller-manager-k8s-master   1/1     Running   0          57m
kube-system   kube-proxy-9l9vr                     1/1     Running   0          58m
kube-system   kube-scheduler-k8s-master            1/1     Running   0          57m
[[email protected] ~]$

安装网络插件

kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"

检查pod

[[email protected] ~]$ kubectl get pod --all-namespaces
NAMESPACE     NAME                                 READY   STATUS    RESTARTS   AGE
kube-system   coredns-5c98db65d4-gpsvq             1/1     Running   0          7h31m
kube-system   coredns-5c98db65d4-st4pf             1/1     Running   0          7h31m
kube-system   etcd-k8s-master                      1/1     Running   0          7h30m
kube-system   kube-apiserver-k8s-master            1/1     Running   0          7h30m
kube-system   kube-controller-manager-k8s-master   1/1     Running   0          7h30m
kube-system   kube-proxy-kx5mv                     1/1     Running   0          7h31m
kube-system   kube-scheduler-k8s-master            1/1     Running   0          7h30m
kube-system   weave-net-57dtf                      2/2     Running   0          59s
[[email protected] ~]$

添加worker节点

[[email protected] ~]$ sudo kubeadm join 192.168.205.120:6443 --token tte278.145ozal6u6e26ypm --discovery-token-ca-cert-hash sha256:cbb168e0665fe1b14e96a87c2da5dc1eeda04c70932ac1913d989753703277bb
[preflight] Running pre-flight checks
	......
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.

[[email protected] ~]$ kubectl get nodes
NAME         STATUS   ROLES    AGE     VERSION
k8s-master   Ready    master   25m     v1.15.3
k8s-node1    Ready    <none>   11m     v1.15.3
k8s-node2    Ready    <none>   5m39s   v1.15.3

[[email protected] ~]$ kubectl get pod --all-namespaces
NAMESPACE     NAME                                 READY   STATUS    RESTARTS   AGE
kube-system   coredns-5c98db65d4-72252             1/1     Running   0          25m
kube-system   coredns-5c98db65d4-x7xf5             1/1     Running   0          25m
kube-system   etcd-k8s-master                      1/1     Running   0          24m
kube-system   kube-apiserver-k8s-master            1/1     Running   0          24m

参考：https://blog.tekspace.io/setup-kubernetes-cluster-on-centos-7/