centos7使用kubeadm搭建kubernetes集群

一、本地实验环境准备

1. 服务器虚拟机准备

IP	CPU	内存	hostname
192.168.222.129	>=2c	>=2G	master
192.168.222.130	>=2c	>=2G	node1
192.168.222.131	>=2c	>=2G	node2

本实验我这里用的虚拟机是vmware workstation创建的，我的机器配置较低，所以master给了4G 4C，node每个给了4G 4C，大家根据自己的资源情况，按照上面给的建议最低值创建即可。
注意：hostname不能有大写字母，比如Master这样的。

1. 软件版本

   系统：CentOS7.5.1804
   Kubernetes：1.15.3
   docker-ce版本：19.03.1

2. 环境初始化操作

2.1 配置hostname

   ## 192.168.222.129
   hostnamectl set-hostname master
   ##  192.168.222.130
   hostnamectl set-hostname node1
   ## 192.168.222.131
   hostnamectl set-hostname node2

2.2 配置三台虚拟机的/etc/hosts

   echo "192.168.222.129 master" >> /etc/hosts
   echo "192.168.222.130 node1" >> /etc/hosts
   echo "192.168.222.131 node2" >> /etc/hosts

2.3 安装必要软件以及升级所有软件,关闭防火墙、selinux、swap

yum -y install vim-enhanced wget curl net-tools conntrack-tools bind-utils socat ipvsadm ipset
yum -y update


## 停防火墙
systemctl stop firewalld systemctl disable firewalld

## 关闭Selinux
sed -i 's#SELINUX=enforcing#SELINUX=disabled#g'  /etc/sysconfig/selinux
sed -i 's#SELINUX=enforcing#SELINUX=disabled#g'  /etc/selinux/config 

## 关闭不必要服务
systemctl disable auditd
systemctl disable postfix
systemctl disable irqbalance
systemctl disable remote-fs
systemctl disable tuned
systemctl disable rhel-configure
systemctl disable firewalld

## 安装kernel-lt(kernel 4.4.178)

rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
yum -y install https://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm
yum --enablerepo=elrepo-kernel install kernel-lt -y

grub2-set-default 0
grub2-mkconfig -o /etc/grub2.cfg

## 优化内核

cat >>/etc/sysctl.conf <<EOF
net.ipv4.ip_forward = 1
vm.swappiness = 0
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.tcp_max_syn_backlog = 65536
net.core.netdev_max_backlog =  32768
net.core.somaxconn = 32768
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_synack_retries = 2
net.ipv4.tcp_syn_retries = 2
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_max_orphans = 3276800
net.ipv4.ip_local_port_range = 1024  65535
EOF

sysctl -p

## 修改文件打开数

cat >>/etc/security/limits.conf <<EOF
* soft memlock unlimited
* hard memlock unlimited
* soft nofile 65535
* hard nofile 65535
* soft nproc 65535
* hard nproc 65535
EOF

## 系统关闭使用交换内存

echo "swapoff -a">>/etc/rc.local
chmod +x /etc/rc.local
swapoff -a

 
## 注释掉/etc/fstab的swap行
# /dev/mapper/centos-swap swap                    swap    defaults        0 0

## 创建k8s.conf
vim /etc/sysctl.d/k8s.conf
## 写入如下配置
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1


## 加载br_netfilter
modprobe br_netfilter

sysctl -p /etc/sysctl.d/k8s.conf

3. 配置CentOS YUM源

   ## 配置国内tencent yum源地址、epel源地址、Kubernetes源地址
   mkdir -p /etc/yum.repo.d/repo.bak
   mv /etc/yum.repo.d/*.repo /etc/yum.repo.d/repo.bak
   wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.cloud.tencent.com/repo/centos7_base.repo
   wget -O /etc/yum.repos.d/epel.repo http://mirrors.cloud.tencent.com/repo/epel-7.repo

配置国内Kubernetes源地址
vim /etc/yum.repos.d/kubernetes.repo

[kubernetes]
name=Kubernetes Repo
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
gpgcheck=0
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
enabled=1

yum clean all && yum makecache

4. 安装一些依赖软件包

   yum install -y conntrack ipvsadm ipset jq sysstat curl iptables libseccomp bash-completion yum-utils device-mapper-persistent-data lvm2 net-tools conntrack-tools vim libtool-ltdl

5. 时间同步配置

   yum install chrony –y systemctl enable chronyd.service && systemctl start chronyd.service && systemctl status chronyd.service chronyc sources

运行date命令看下系统时间，过一会儿时间就会同步。如果同步失败检查是不是因为公司内部网导致无法同步时间

6. 以上操作后，全部重启一下。

7. 安装docker

## 配置docker yum 源
cd /etc/yum.repos.d && wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

## 查看docker-ce的可用资源
yum list docker-ce.x86_64 --showduplicates | sort -r 

会显示如下的docker-ce信息

Repository cr is listed more than once in the configuration
Repository fasttrack is listed more than once in the configuration
已加载插件：fastestmirror, langpacks
已安装的软件包
可安装的软件包
Loading mirror speeds from cached hostfile
 * elrepo: mirrors.tuna.tsinghua.edu.cn
docker-ce.x86_64            3:19.03.1-3.el7                    docker-ce-stable 
docker-ce.x86_64            3:19.03.1-3.el7                    @docker-ce-stable
docker-ce.x86_64            3:19.03.0-3.el7                    docker-ce-stable 
docker-ce.x86_64            3:18.09.8-3.el7                    docker-ce-stable 
docker-ce.x86_64            3:18.09.7-3.el7                    docker-ce-stable 
docker-ce.x86_64            3:18.09.6-3.el7                    docker-ce-stable 
docker-ce.x86_64            3:18.09.5-3.el7                    docker-ce-stable 
docker-ce.x86_64            3:18.09.4-3.el7                    docker-ce-stable 
docker-ce.x86_64            3:18.09.3-3.el7                    docker-ce-stable 
docker-ce.x86_64            3:18.09.2-3.el7                    docker-ce-stable 
docker-ce.x86_64            3:18.09.1-3.el7                    docker-ce-stable 
docker-ce.x86_64            3:18.09.0-3.el7                    docker-ce-stable 
docker-ce.x86_64            18.06.3.ce-3.el7                   docker-ce-stable 
docker-ce.x86_64            18.06.2.ce-3.el7                   docker-ce-stable 
docker-ce.x86_64            18.06.1.ce-3.el7                   docker-ce-stable 
docker-ce.x86_64            18.06.0.ce-3.el7                   docker-ce-stable 
docker-ce.x86_64            18.03.1.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            18.03.0.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.12.1.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.12.0.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.09.1.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.09.0.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.06.2.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.06.1.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.06.0.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.03.3.ce-1.el7                   docker-ce-stable 
docker-ce.x86_64            17.03.2.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.03.1.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.03.0.ce-1.el7.centos            docker-ce-stable

选择你想要得版本，我使用了最新版本

 yum -y  install docker-ce 

配置镜像加速器和docker数据存放路径

vim /etc/docker/daemon.json
写入如下配置

{ 
	"registry-mirrors": ["https://q2hy3fzi.mirror.aliyuncs.com"], 
    "graph": "/tol/docker-data" ,
    "exec-opts":["native.cgroupdriver=systemd"]
} 

设置自启动

 systemctl enable docker && systemctl start docker

8. 安装 kubeadm、kubelet、kubectl K8S_VERSION=v1.15.3

 cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
        http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

 yum install -y  kubeadm kubelet  kubectl 
 
 kubelet --version //v1.15.3

kubelet启动设置

vim /etc/sysconfig/kubelet
写入如下配置

KUBELET_EXTRA_ARGS="--fail-swap-on=false"

再重启

 systemctl daemon-reload  

9. master节点设置(192.168.222.129)

下载相关镜像

#!/bin/bash
# master 节点 shell
K8S_VERSION=v1.15.3
ETCD_VERSION=3.3.10
DNS_VERSION=1.3.1
PAUSE_VERSION=3.1
FLANNEL_VERSION=v0.11.0-amd64
DASHBOARD_VERSION=v1.10.1

// 下载镜像
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:$K8S_VERSION
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:$K8S_VERSION
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:$K8S_VERSION
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:$K8S_VERSION
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/pause:$PAUSE_VERSION
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:$ETCD_VERSION
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:$DNS_VERSION
docker pull jmgao1983/flannel:$FLANNEL_VERSION
docker pull siriuszg/kubernetes-dashboard-amd64:$DASHBOARD_VERSION

# 修改tag
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:$K8S_VERSION           k8s.gcr.io/kube-apiserver:$K8S_VERSION
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:$K8S_VERSION  k8s.gcr.io/kube-controller-manager:$K8S_VERSION
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:$K8S_VERSION           k8s.gcr.io/kube-scheduler:$K8S_VERSION
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:$K8S_VERSION               k8s.gcr.io/kube-proxy:$K8S_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/etcd:$ETCD_VERSION                    k8s.gcr.io/etcd:$ETCD_VERSION
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:$DNS_VERSION  			     k8s.gcr.io/coredns:$DNS_VERSION
docker tag jmgao1983/flannel:$FLANNEL_VERSION                              							 quay.io/coreos/flannel:$FLANNEL_VERSION
docker tag siriuszg/kubernetes-dashboard-amd64:$DASHBOARD_VERSION                                    k8s.gcr.io/kubernetes-dashboard-amd64:$DASHBOARD_VERSION

#删除冗余的images
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:$K8S_VERSION
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:$K8S_VERSION
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:$K8S_VERSION
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:$K8S_VERSION
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/pause:$PAUSE_VERSION
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:$ETCD_VERSION
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:$DNS_VERSION
docker rmi jmgao1983/flannel:$FLANNEL_VERSION
docker rmi siriuszg/kubernetes-dashboard-amd64:$DASHBOARD_VERSION

集群安装初始化(192.168.222.129)

## 初始化命令
 kubeadm init --kubernetes-version=v1.15.3 --pod-network-cidr=10.244.0.0/16 --ignore-preflight-errors=Swap 

这时候出现如下信息表明安装成功

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 192.168.222.129:6443 --token 981it6.k4kqs2i73e1bfd1p 
    --discovery-token-ca-cert-hash sha256:5cc5c1c2ace7b720a178840c951b2a05c679d26b8d6a1cfc81aa7e006e6a6ef9 

按照上面的提示执行推荐操作

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

查看集群健康状况

 kubectl get cs

集群安装过程中遇到问题，重置操作,如需执行此操作，所有节点都需要执行（报错时使用,不报错不用）

 kubeadm reset

安装网络插件

kube-flannel.yml 文件需要自己下载上传

 kubectl apply -f ./kube-flannel.yml

查看集群中的组件运行状态

 kubectl get pods --all-namespaces

10. node节点设置(192.168.222.130和192.168.222.131子节点配置)

下载镜像

#!/bin/bash
# node 节点 shell
K8S_VERSION=v1.15.3
ETCD_VERSION=3.3.10
DNS_VERSION=1.3.1
PAUSE_VERSION=3.1
FLANNEL_VERSION=v0.11.0-amd64
DASHBOARD_VERSION=v1.10.1

## node 安装插件
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:$K8S_VERSION
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/pause:$PAUSE_VERSION
docker pull jmgao1983/flannel:v0.11.0-amd64
docker pull siriuszg/kubernetes-dashboard-amd64:$DASHBOARD_VERSION


docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:$K8S_VERSION  k8s.gcr.io/kube-proxy:$K8S_VERSION
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/pause:$PAUSE_VERSION     k8s.gcr.io/pause:$PAUSE_VERSION
docker tag jmgao1983/flannel:$FLANNEL_VERSION                                           quay.io/coreos/flannel:$FLANNEL_VERSION
docker tag siriuszg/kubernetes-dashboard-amd64:$DASHBOARD_VERSION                       k8s.gcr.io/kubernetes-dashboard-amd64:$DASHBOARD_VERSION


docker rmi jmgao1983/flannel:$FLANNEL_VERSION
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/pause:$PAUSE_VERSION
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:$K8S_VERSION
docker rmi siriuszg/kubernetes-dashboard-amd64:$DASHBOARD_VERSION

加入节点

这里的信息在主节点初始化完成后会出现，按照自己初始化完后的信息操作，这里仅供参考

 kubeadm join 192.168.222.129:6443 --token 9ump71.6fnndushlwn87fnf 
    --discovery-token-ca-cert-hash sha256:addb0cd073a460331fe4cadd1f02c69e9b1bdad4e62188fae788ff65e0a8fb11 --ignore-preflight-errors=Swap

出现下面的信息表明子节点加入主节点成功,可以使用该命令 kubectl get nodes查看

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.

如果执行上述命令报The connection to the server localhost:8080 was refused - did you specify the right host or port?

操作如下

1. 将主节点中的【/etc/kubernetes/admin.conf】文件拷贝到从节点相同目录下
2. echo "export KUBECONFIG=/etc/kubernetes/admin.conf" >> ~/.bash_profile
3. source ~/.bash_profile

11. 安装 dashboard组件(我是在主节点上操作的)

配置dashboard

kubectl create -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0-beta1/aio/deploy/recommended.yaml

集群配置，生成浏览器证书(这些证书在后面浏览器打开dashboard时需要导入)

# 生成client-certificate-data
grep 'client-certificate-data' ~/.kube/config | head -n 1 | awk '{print $2}' | base64 -d >> kubecfg.crt

# 生成client-key-data
grep 'client-key-data' ~/.kube/config | head -n 1 | awk '{print $2}' | base64 -d >> kubecfg.key

# 生成p12
openssl pkcs12 -export -clcerts -inkey kubecfg.key -in kubecfg.crt -out kubecfg.p12 -name "kubernetes-client"

# 导入证书后浏览器重启

创建admin-user账号，并放在kube-system名称空间下

vim admin-user.yaml
写入如下配置

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

使用该命令加载配置

kubectl create -f admin-user.yaml

绑定角色

vim admin-user-role-binding.yaml
写入如下配置

apiVersion: rbac.authorization.k8s.io/v1beta1
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

使用该命令加载配置

kubectl create -f  admin-user-role-binding.yaml

登录dashboard

在浏览器中访问如下url

https://127.0.0.1:6443/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/

在打开的页面中选择token方式,获取token的方式如下

kubectl -n kube-system describe secret $(kubectl -n kube-system get secret | grep admin-user | awk '{print $1}')

12. 集成Heapster

Heapster是容器集群监控和性能分析工具

执行命令

kubectl create -f http://mirror.faasx.com/kubernetes/heapster/deploy/kube-config/influxdb/influxdb.yaml
kubectl create -f http://mirror.faasx.com/kubernetes/heapster/deploy/kube-config/influxdb/grafana.yaml
kubectl create -f http://mirror.faasx.com/kubernetes/heapster/deploy/kube-config/influxdb/heapster.yaml
kubectl create -f http://mirror.faasx.com/kubernetes/heapster/deploy/kube-config/rbac/heapster-rbac.yaml

当pod的状态全都变成了running，则能够使用。

补充

初始化获取要下载的镜像列表
使用kubeadm来搭建Kubernetes，那么就需要下载得到Kubernetes运行的对应基础镜像，比如：kube- proxy、kube-apiserver、kube-controller-manager等等 。那么有什么方法可以得知要下载哪些镜像 呢？从kubeadm v1.11+版本开始，增加了一个kubeadm config print-default 命令，可以让我们方便 的将kubeadm的默认配置输出到文件中，这个文件里就包含了搭建K8S对应版本需要的基础配置环境。另 外，我们也可以执行 kubeadm config images list 命令查看依赖需要安装的镜像列表。

kubeadm config images list

网络除了使用flannel也可以使用calico具体参考Quickstart for Calico on Kubernetes

参考

Kubeadm安装Kubernetes 1.15.1

kubeadm 虚拟机实践