使用kubeadm部署Kubernetes集群

一、环境架构与部署准备

　　1.集群节点架构与各节点所需安装的服务如下图：

　　2.安装环境与软件版本：

　　Master：

所需软件：docker-ce 17.03、kubelet1.11.1、kubeadm1.11.1、kubectl1.11.1

所需镜像：

　　mirrorgooglecontainers/kube-proxy-amd64:v1.11.1、mirrorgooglecontainers/kube-scheduler-amd64:v1.11.1、mirrorgooglecontainers/kube-controller-manager-amd64:v1.11.1、mirrorgooglecontainers/kube-apiserver-amd64:v1.11.1、coredns/coredns:1.1.3、mirrorgooglecontainers/etcd-amd64:3.2.18、mirrorgooglecontainers/pause:3.1、registry.cn-hangzhou.aliyuncs.com/readygood/flannel:v0.10.0-amd64

　　Node：

所需软件：docker-ce 17.03、kubelet1.11.1、kubeadm1.11.1

所需镜像：mirrorgooglecontainers/kube-proxy-amd64:v1.11.1、mirrorgooglecontainers/pause:3.1、registry.cn-hangzhou.aliyuncs.com/readygood/flannel:v0.10.0-amd64

二、部署Master

　　1.关闭Firewall和SELinux

由于kubeadm在初始化时会自动生成ipv4规则，所以尽量在部署前关闭防火墙。

　　2.配置阿里云的Kubernetes镜像和Docker-ce镜像并安装

K8s yum源配置：

[k8s]
name=k8s
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
gpgchecke=
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
enabled=

Docker-ce源配置：

wget -o /etc/yum.repos.d/ https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

修改Docker镜像默认拉取源：

mkdir -p /etc/docker
vim /etc/docker/daemon.json
{
"registry-mirrors": ["https://registry.docker-cn.com"]
}

安装注意指定版本：

yum install -y --setopt=obsoletes=    docker-ce-17.03..ce-.el7.centos.x86_64    docker-ce-selinux-17.03..ce-.el7.centos.noarch
yum install kubelet-1.11. kubeadm-1.11. kubectl-1.11.1 -y

　　3.设置内核转发规则，即要求iptables对bridge的数据进行处理，默认为0.

echo  > /proc/sys/net/bridge/bridge-nf-call-iptables

　　4.关闭或者忽略swap，部署Kubernetes集群时尽量不要使用swap分区，Kubernetes会提示是否要关闭或者忽略，忽略方式如下：

vim /etc/sysconfig/kubelet
KUBELET_EXTRA_ARGS="--fail-swap-on=false"

　　5.初始化Kubernetes

kubeadm init --kubernetes-version=1.11. --pod-network-cidr=10.244.0.0/ --service-cidr=10.96.0.0/ --ignore-preflight-errors=Swap

　　如果在初始化中出现错误可以使用 kubeadm reset 重置初始化，如果出现" [kubelet-check] It seems like the kubelet isn't running or healthy. "的错误，建议检查swap设置。

　　初始化完成会出现如下提示，按提示完成操作初始化便完成，最后一段数字一定要保留下来，这是加入集群必须要的认证信息：

Your Kubernetes master has initialized successfully!

To start using your cluster, you need to run the following 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 options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/

You can now join any number of machines by running the following on each node
as root:
    kubeadm join 192.168.29.111: --token 4qswp9.rxgwhn0vqp4c9npl --discovery-token-ca-cert-hash sha256:2d9bc0bd6b1eb12dcb8695f17191b243ecf3ed169d4aafaacc5c5c1272a85f07

　　6.关于运行Kubernetes所需镜像下载的问题：

由于某些原因无法正常下载官方镜像，但Kubeadm只支持认证官方的镜像标签，所以必须在dockerhub上下载镜像后修改标签才能使用，可使用dockerhub或者阿里云镜像，然后修改标签名：

mirrorgooglecontainers/kube-proxy-amd64
mirrorgooglecontainers/kube-apiserver-amd64
mirrorgooglecontainers/kube-scheduler-amd64
mirrorgooglecontainers/kube-controller-manager-amd64
coredns/coredns
mirrorgooglecontainers/etcd-amd64
mirrorgooglecontainers/pause

k8s.gcr.io/kube-proxy-amd64                v1.11.1             d5c25579d0ff         weeks ago         .8MB
k8s.gcr.io/kube-scheduler-amd64            v1.11.1             272b3a60cd68         weeks ago         .8MB
k8s.gcr.io/kube-controller-manager-amd64   v1.11.1             52096ee87d0e         weeks ago         155MB
k8s.gcr.io/kube-apiserver-amd64            v1.11.1             816332bd9d11         weeks ago         187MB
k8s.gcr.io/coredns                         1.1.               b3b94275d97c         months ago        .6MB
k8s.gcr.io/etcd-amd64                      3.2.              b8df3b177be2         months ago        219MB
quay.io/coreos/flannel                     v0.10.0-amd64       f0fad859c909         months ago        .6MB
k8s.gcr.io/pause                           3.1                 da86e6ba6ca1         months ago        742kB

　　7.关于flannel的安装

在确定已经下载镜像 quay.io/coreos/flannel 后（能访问谷歌请忽略），运行下面的命令。

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

三、Nodes部署

　　1.安装node所需组件

　　和master一样，需要安装docker、kubeadm、kubelet，并设置开机自启，步骤参考master，这里不赘述了。下载好Node所需镜像，并重命名为k8s.gcr.io/：

mirrorgooglecontainers/kube-proxy-amd64               v1.11.1             d5c25579d0ff         months ago        97.8 MB
registry.cn-hangzhou.aliyuncs.com/readygood/flannel   v0.10.0-amd64       50e7aa4dbbf8         months ago        44.6 MB
registry.cn-hangzhou.aliyuncs.com/readygood/pause     3.1                 da86e6ba6ca1         months ago        kB

　　docker镜像下载完成后初始化flannel服务：

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

　　2.初始化node节点

kubeadm join 192.168.29.111: --token 4qswp9.rxgwhn0vqp4c9npl --discovery-token-ca-cert-hash sha256:2d9bc0bd6b1eb12dcb8695f17191b243ecf3ed169d4aafaacc5c5c1272a85f07 --ignore-preflight-errors=Swap

　　如果不关闭swap同样需要配置swap设置以及修改iptables对bridge的数据进行处理设置：

vim /etc/sysconfig/kubelet
KUBELET_EXTRA_ARGS="--fail-swap-on=false"
echo 1 > /proc/sys/net/bridge/bridge-nf-call-iptables

　　出现如下提示即初始化完成：

This node has joined the cluster:
* Certificate signing request was sent to master and a response
  was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the master to see this node join the cluster.

　　查看集群状态：

]# kubectl get pods -n kube-system -o wide
NAME                             READY     STATUS    RESTARTS   AGE       IP               NODE
coredns-78fcdf6894-kpt2k         /       Running             18h       10.244.0.5       master
coredns-78fcdf6894-nzdkz         /       Running             18h       10.244.0.4       master
etcd-master                      /       Running             16h       192.168.29.111   master
kube-apiserver-master            /       Running             16h       192.168.29.111   master
kube-controller-manager-master   /       Running             16h       192.168.29.111   master
kube-flannel-ds-amd64-5gnd8      /       Running             16h       192.168.29.111   master
kube-flannel-ds-amd64-7rtb8      /       Running             2h        192.168.29.112   node1
kube-flannel-ds-amd64-qqjdv      /       Running             2h        192.168.29.113   node2
kube-proxy-kfsfj                 /       Running             2h        192.168.29.113   node2
kube-proxy-lnk67                 /       Running             2h        192.168.29.112   node1
kube-proxy-v8d2q                 /       Running             18h       192.168.29.111   master
kube-scheduler-master            /       Running             16h       192.168.29.111   master

]# kubectl get nodes -o wide
NAME      STATUS    ROLES     AGE       VERSION   INTERNAL-IP      EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION          CONTAINER-RUNTIME
master    Ready     master    18h       v1.11.1   192.168.29.111   <none>        CentOS Linux  (Core)   3.10.-.el7.x86_64   docker://17.3.2
node1     Ready     <none>    2h        v1.11.1   192.168.29.112   <none>        CentOS Linux  (Core)   3.10.-.el7.x86_64   docker://17.3.2
node2     Ready     <none>    2h        v1.11.1   192.168.29.113   <none>        CentOS Linux  (Core)   3.10.-.el7.x86_64   docker://17.3.2

　　还需要特别注意的是，各Node之间的主机名不要相同，一定要修改，不然Kubeadm会识别为同一Node而无法加入。

Node2和Node3的部署和Node1相同，可以完全按照Node1的方法来部署。