使用kubeadm搭建k8s集群

现在docker,k8s那么火，我们肯定也要玩一玩得嘛，那么我们就得搭建个k8s集群环境来好好感受感受下k8s的魅力，个人感觉可以先从单机的minikube感受下，熟悉之后再来搭建多服务器的k8s集群，下面就我搭建多服务器k8s集群的过程记录下来，供大家参考

1，环境

      3台vm虚拟机 比如192.168.2.100（master） 192.168.2.101(node1) 192.168.2.102(node2) vm系统为centos7

[[email protected] ~]# uname -a
Linux centos7-01 3.10.0-862.el7.x86_64 #1 SMP Fri Apr 20 16:44:24 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

2.准备工作

 docker,k8s.gcr.io的相关镜像

2.1 安装docker

yum update
yum install -y docker

安装完成之后

systemctl enable docker && systemctl start docker

可以查看下docker版本 已经是否启动成功

docker version
systemctl status docker

docker解决之后解决镜像问题

2.2 k8s集群搭建的一个难点就是k8s.gcr.io的镜像被墙的困难，这里我给大家提供下我下载的镜像

链接：https://pan.baidu.com/s/1-03BTghvOKWNGzrwN2A-JA 
提取码：lecc

下载之后上传到服务器，解压

用docker加载镜像

docker load -i k8s.images.tar

给镜像打上正确的标签

chmod 777 docker-load.sh
bash docker-load.sh

查看是否有镜像了

[[email protected] ~]# docker images
REPOSITORY                           TAG                 IMAGE ID            CREATED             SIZE
k8s.gcr.io/kube-proxy                v1.14.1             20a2d7035165        3 days ago          82.1MB
k8s.gcr.io/kube-apiserver            v1.14.1             cfaa4ad74c37        3 days ago          210MB
k8s.gcr.io/kube-controller-manager   v1.14.1             efb3887b411d        3 days ago          158MB
k8s.gcr.io/kube-scheduler            v1.14.1             8931473d5bdb        3 days ago          81.6MB
k8s.gcr.io/coredns                   1.3.1               eb516548c180        2 months ago        40.3MB
k8s.gcr.io/etcd                      3.3.10              2c4adeb21b4f        4 months ago        258MB
quay.io/coreos/flannel               v0.10.0-amd64       0abc30f2e842        6 months ago        44.6MB
k8s.gcr.io/pause                     3.1                 da86e6ba6ca1        15 months ago       742kB
[[email protected] ~]# 

2.3这两步完成之后配置相关系统环境

2.3.1 关闭防火墙 

systemctl disable firewalld && systemctl stop firewalld

2.3.2 关闭SELINUX

vim /etc/selinux/config

改为
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing - SELinux security policy is enforced.
#     permissive - SELinux prints warnings instead of enforcing.
#     disabled - No SELinux policy is loaded.
#SELINUX=enforcing
SELINUX=disabled
# SELINUXTYPE= can take one of three two values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected. 
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted

并 setenforce 0

2.3.3 关闭swap (注释有swap的哪一行)

swapoff -a


vim /etc/fstab#
# /etc/fstab
# Created by anaconda on Fri Mar  8 11:26:03 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root /                       xfs     defaults        0 0
UUID=b7107ef6-ed73-492a-b9a7-8bdb0d6201a4 /boot                   xfs     defaults        0 0
#/dev/mapper/centos-swap swap                    swap    defaults        0 0

3 环境好了之后开始安装 kubectl kubeamd kubelet

官方仓库无法使用，建议使用阿里源的仓库，执行以下命令添加kubernetes.repo仓库

 
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
 

然后用yum安装

yum install -y kubelet kubeadm kubectl

安装完成之后执行（这一步可以解决启动之后 The connection to the server localhost:8080 was refused - did you specify the right host or port? 这个问题，特别是node用kubectl命令时）

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

安装flannel网络组件，上一步的images中有flannel的相关镜像，现在就不用下载了

操作如下

echo 1 > /proc/sys/net/bridge/bridge-nf-call-iptables
echo 1 > /proc/sys/net/bridge/bridge-nf-call-ip6tables


mkdir -p /etc/cni/net.d/
cat <<EOF> /etc/cni/net.d/10-flannel.conf
{"name":"cbr0","type":"flannel","delegate": {"isDefaultGateway": true}}
EOF
mkdir /usr/share/oci-umount/oci-umount.d -p
mkdir /run/flannel/
cat <<EOF> /run/flannel/subnet.env
FLANNEL_NETWORK=172.100.0.0/16
FLANNEL_SUBNET=172.100.1.0/24
FLANNEL_MTU=1450
FLANNEL_IPMASQ=true
EOF

然后在master服务器上启动kubelet

kubeadm init --pod-network-cidr=192.168.0.0/16 --kubernetes-version=v1.14.1

 

(在node服务器上加入k8s集群组

在master服务器上 输入kubeadm token create --print-join-command

复制信息到node 节点上

kubeadm join 192.168.2.100:6443 --token 2oa1ge.3zz9m5kvs02n0goy     --discovery-token-ca-cert-hash sha256:8a63f7379979198f93a9aa554b68d6d2dc0147a95196e010c1a1ce1e6ba10641)

（）这一步是在node上操作的，请先让master节点跑起来

 

在master节点 启动flannel

kubectl create -f kube-flannel.yml

master好了之后然后node的操作同上

查看node 

kubectl get nodes

NAME         STATUS   ROLES    AGE     VERSION
centos7-01   Ready    master   25h     v1.14.1
centos7-02   Ready    <none>   3h25m   v1.14.1
centos7-03   Ready    <none>   81m     v1.14.1
centos7-04   Ready    <none>   8h      v1.14.1

如上图就是好了

看pod信息

[[email protected] bridge]# kubectl get pod --all-namespaces -o wide
NAMESPACE     NAME                                 READY   STATUS    RESTARTS   AGE     IP              NODE         NOMINATED NODE   READINESS GATES
default       nginx-deploy-5f5d9f64f6-9gl7w        1/1     Running   0          6h24m   10.244.2.2      centos7-04   <none>           <none>
default       nginx-deploy-5f5d9f64f6-hl56z        1/1     Running   0          61m     10.244.4.5      centos7-02   <none>           <none>
default       nginx-deploy-5f5d9f64f6-ppm7l        1/1     Running   0          61m     10.244.5.2      centos7-03   <none>           <none>
kube-system   coredns-fb8b8dccf-dg9lv              1/1     Running   0          25h     172.100.1.4     centos7-01   <none>           <none>
kube-system   coredns-fb8b8dccf-rlqsw              1/1     Running   0          25h     172.100.1.5     centos7-01   <none>           <none>
kube-system   etcd-centos7-01                      1/1     Running   0          25h     192.168.2.121   centos7-01   <none>           <none>
kube-system   kube-apiserver-centos7-01            1/1     Running   0          25h     192.168.2.121   centos7-01   <none>           <none>
kube-system   kube-controller-manager-centos7-01   1/1     Running   0          25h     192.168.2.121   centos7-01   <none>           <none>
kube-system   kube-flannel-ds-5ldmv                1/1     Running   0          65m     192.168.2.111   centos7-03   <none>           <none>
kube-system   kube-flannel-ds-cnpwj                1/1     Running   0          3h19m   192.168.2.106   centos7-02   <none>           <none>
kube-system   kube-flannel-ds-tbbzg                1/1     Running   2          7h59m   192.168.2.113   centos7-04   <none>           <none>
kube-system   kube-flannel-ds-vqmbk                1/1     Running   0          25h     192.168.2.121   centos7-01   <none>           <none>
kube-system   kube-proxy-885qw                     1/1     Running   0          25h     192.168.2.121   centos7-01   <none>           <none>
kube-system   kube-proxy-jvbkv                     1/1     Running   3          8h      192.168.2.113   centos7-04   <none>           <none>
kube-system   kube-proxy-mkppj                     1/1     Running   0          3h26m   192.168.2.106   centos7-02   <none>           <none>
kube-system   kube-proxy-x8bqp                     1/1     Running   0          82m     192.168.2.111   centos7-03   <none>           <none>
kube-system   kube-scheduler-centos7-01            1/1     Running   0          25h     192.168.2.121   centos7-01   <none>           <none>

如图所示应该就是没什么问题了