虚拟机centos7环境搭建k8s集群-实践篇

楼主环境：笔记本一台，内存16G, 硬盘500G，Oracle VM VirtualBox新建两个centos7虚拟机（2核cpu 内存4G 硬盘20G）
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环境准备

虚拟机联网配置：

1. 设置网卡连接方式 (master/node)

设置-网络-网卡1-连接方式[桥接方式]

2. 静态ip配置(master/node)

#vim 没安装时使用vi代替(蓝色部分为修改或新增部分)
$ vim /etc/sysconfig/network-scripts/ifcfg-enp0s3  
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=static
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=enp0s3
UUID=1532ae46-52e7-4f1e-8032-1a9bbc55d393
DEVICE=enp0s3
ONBOOT=yes

#以下是静态ip配置时新增内容
IPADDR=192.168.100.215  #此处给自己设置一个静态ip
NETMASK=255.255.255.0
GATEWAY=192.168.100.1
DNS1=119.29.29.29
DNS2=223.5.5.5

$ service network restart

详细步骤

1. 虚拟机两台（ip按自己的网络环境相应配置）(master/node)

2. 关闭防火墙(master/node)

 systemctl stop firewalld
 systemctl disable firewalld

3. 关闭selinux(master/node)

setenforce 0  # 临时关闭
sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config # 永久关闭

4. 关闭swap(master/node)

swapoff -a    # 临时关闭；关闭swap主要是为了性能考虑
free             # 可以通过这个命令查看swap是否关闭了
sed -ri 's/.*swap.*/#&/' /etc/fstab  # 永久关闭

5. 添加主机名与IP对应的关系(master/node)

 $ vim /etc/hosts
 #添加如下内容：
192.168.100.215     k8s-master
192.168.100.216     k8s-node1
#保存退出

6. 修改主机名(master/node)

k8s-master:

[root@localhost ~] hostname
localhost.localdomain
[root@localhost ~] hostname k8s-master ##临时生效
[root@localhost ~] hostnamectl set-hostname k8s-master ##重启后永久生效

k8s-node1:

[root@localhost ~] hostname
localhost.localdomain
[root@localhost ~] hostname k8s-node1  ##临时生效
[root@localhost ~] hostnamectl set-hostname k8s-node1  ##重启后永久生效

7. 桥接设置(master/node)

$ cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
$ sysctl --system

8. 安装docker(master/node)

$ yum -y install wget
# 添加docker yum源
$ wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O/etc/yum.repos.d/docker-ce.repo
# 安装
$ yum -y install docker-ce
# 设置开机启动
$ systemctl enable docker
# 启动docker
$ systemctl start docker

9. 添加阿里云YUM软件源(master/node)

cat > /etc/yum.repos.d/kubernetes.repo << EOF
[k8s]
name=k8s
enabled=1
gpgcheck=0 
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
EOF

10. 安装kubeadm，kubelet和kubectl(master/node)

$ yum install -y kubelet-1.17.0 kubectl-1.17.0 kubeadm-1.17.0
# 此时，还不能启动kubelet，因为此时配置还不能，现在仅仅可以设置开机自启动
$ systemctl enable kubelet

11. 部署Kubernetes (master)

• 11.1 kubeadm init

kubeadm init \
  --apiserver-advertise-address=192.168.100.215 \
  --image-repository registry.aliyuncs.com/google_containers \
  --kubernetes-version v1.17.0 \
  --service-cidr=10.1.0.0/16 \
  --pod-network-cidr=10.244.0.0/16

成功后末尾输出信息如下：

kubeadm join 192.168.100.215:6443 --token 5l6xl0.qwifh1s0hrxdss3f \
    --discovery-token-ca-cert-hash sha256:cfd498dd8bb0e0d88cc45a795941906911dabc65f9251ae5479e5fb6ac85a472

查看安装的镜像

$  docker images
REPOSITORY                                                        TAG                 IMAGE ID            CREATED             SIZE
registry.aliyuncs.com/google_containers/kube-proxy                v1.17.0             7d54289267dc        7 months ago        116MB
registry.aliyuncs.com/google_containers/kube-apiserver            v1.17.0             0cae8d5cc64c        7 months ago        171MB
registry.aliyuncs.com/google_containers/kube-controller-manager   v1.17.0             5eb3b7486872        7 months ago        161MB
registry.aliyuncs.com/google_containers/kube-scheduler            v1.17.0             78c190f736b1        7 months ago        94.4MB
registry.aliyuncs.com/google_containers/coredns                   1.6.5               70f311871ae1        8 months ago        41.6MB
registry.aliyuncs.com/google_containers/etcd                      3.4.3-0             303ce5db0e90        9 months ago        288MB
registry.aliyuncs.com/google_containers/pause                     3.1                 da86e6ba6ca1        2 years ago         742kB

• 11.2 使用kubectl工具

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

测试一下kubectl命令

[root@k8s-master ~]# kubectl get nodes
NAME         STATUS   ROLES    AGE   VERSION
k8s-master   Ready    master   23m   v1.17.0
k8s-node1    Ready    <none>   19m   v1.17.0

12. 安装Pod网络插件(master/node)

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

报错：The connection to the server raw.githubusercontent.com was refused - did you specify the right host or port?
原因：外网不可访问
解决办法：

sudo vim /etc/hosts199.232.28.133 raw.githubusercontent.com

重新执行上面命令，便可成功安装！

13. node节点加入master(node)

kubeadm join 192.168.100.215:6443 --token 5l6xl0.qwifh1s0hrxdss3f \
    --discovery-token-ca-cert-hash sha256:cfd498dd8bb0e0d88cc45a795941906911dabc65f9251ae5479e5fb6ac85a472

在master查看

$ kubectl get nodes
NAME         STATUS     ROLES    AGE   VERSION
k8s-master   NotReady   master   22m   v1.17.0
k8s-node1    Ready      <none>   18m   v1.17.0

至此，主从双节点集群搭建完毕，后续部署相关，敬请期待！
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参考文章