技术之路

 

环境介绍：

centos 7.4.1708 关闭selinux和iptable，环境很重要！

温馨提示：本文中以有......为底色的命令，都需要执行

k8s-master节点安装

第一步：安装docker

yum install -y yum-utils device-mapper-persistent-data lvm2

wget -O /etc/yum.repos.d/docker-ce.repo https://download.docker.com/linux/centos/docker-ce.repo

sed -i 's+download.docker.com+mirrors.tuna.tsinghua.edu.cn/docker-ce+' /etc/yum.repos.d/docker-ce.repo

yum install docker-ce -y

systemctl enable docker.service

systemctl start docker.service

 

第二步：安装kubeadm和kubelet

a：添加k8s的yum源（目前仅发现阿里云有yum源）

cat <<EOF > /etc/yum.repos.d/kubernetes.repo

[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

EOF

 

b：安装kubeadm和kubelet

yum install -y kubelet kubeadm kubectl ipvsadm

#ipvsadm是lvs的管理工具，新版k8s支持使用lvs做内部的负载均衡

 

c：内核优化

cat <<EOF > /etc/sysctl.d/k8s.conf

net.bridge.bridge-nf-call-ip6tables = 1

net.bridge.bridge-nf-call-iptables = 1

vm.swappiness=0

EOF

sysctl --system

systemctl enable kubelet.service

 

第三步：使用kubeadm初始化k8s的master节点

kubeadm init --apiserver-advertise-address=10.0.0.11 --image-repository registry.aliyuncs.com/google_containers --service-cidr=10.254.0.0/16 --pod-network-cidr=172.16.0.0/16

#这一步很容易失败

成功会有如下类似的输出：

Your Kubernetes master has initializedsuccessfully!

 

To start using your cluster, you need to run thefollowing 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 runningthe following on each node

as root:

 

kubeadm join 10.0.0.11:6443 --token 53h5el.u4oy0hxukuks9n3d --discovery-token-ca-cert-hash sha256:f0514233ef67c5a1da08661cf61ea78c95b0e72da72a8c80f452904ce581c9ce

 

首先按照提示拷贝下k8s的config文件

mkdir -p $HOME/.kube

sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

sudo chown $(id -u):$(id -g) $HOME/.kube/config

其次把kubeadm join 10.0.0.11:6443 --token 53h5el.u4oy0hxukuks9n3d --discovery-token-ca-cert-hash sha256:f0514233ef67c5a1da08661cf61ea78c95b0e72da72a8c80f452904ce581c9ce的信息保存好，后期利用kubeadm添加node节点需要用到

 

检查k8s集群的状态：

kubectl get cs

 

第四步：为k8s配置网络

查看k8s的节点

kubectl get nodes

发现它的状态为NotReady，这是因为我们还没有为k8s按照网络插件，网络插件有多种方案，这里我们使用flannel.

wget https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.yml

vim kube-flannel.yml

76行修改为："Network": "172.16.0.0/16", #kubeadm初始化的时候，我们用的--pod-network-cidr=172.16.0.0/16，网段需要修改为一致。

103行下面增加如下3行：

- key: node.kubernetes.io/not-ready

operator: Exists

effect: NoSchedule

110行和124行：registry.cn-shanghai.aliyuncs.com/gcr-k8s/flannel:v0.10.0-amd64 #网络原因，修改为国内地址，下载更快

130行增加一行：

- --iface=eth0 #根据自己的物理网卡名称来

 

kubectl apply -f kube-flannel.yml

kubectl get pods --namespace kube-system

#主要是看看kube-flannel-ds开头的pod是否已经Running，完成了，在往下走

kubectl get nodes

#这时NotReady状态已变为Ready，至此k8s master节点完成

 

k8s-node1节点安装

第一步：安装docker

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

yum install -y yum-utils device-mapper-persistent-data lvm2

wget -O /etc/yum.repos.d/docker-ce.repo https://download.docker.com/linux/centos/docker-ce.repo

sed -i 's+download.docker.com+mirrors.tuna.tsinghua.edu.cn/docker-ce+' /etc/yum.repos.d/docker-ce.repo

yum install docker-ce -y

systemctl enable docker.service

systemctl start docker.service

 

第二步：安装kubelet kubeadm

a：添加k8s的yum源（目前仅发现阿里云有yum源）

cat <<EOF > /etc/yum.repos.d/kubernetes.repo

[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

EOF

 

b：安装kubeadm和kubelet

yum install -y kubelet kubeadm kubectl ipvsadm

 

c：内核优化

cat <<EOF > /etc/sysctl.d/k8s.conf

net.bridge.bridge-nf-call-ip6tables = 1

net.bridge.bridge-nf-call-iptables = 1

vm.swappiness=0

EOF

sysctl --system

systemctl enable kubelet.service

 

第三步：使用kubeadm加入集群

kubeadm join 10.0.0.11:6443 --token 53h5el.u4oy0hxukuks9n3d --discovery-token-ca-cert-hash sha256:f0514233ef67c5a1da08661cf61ea78c95b0e72da72a8c80f452904ce581c9ce

#这个命令如果当时没保存，可以在master节点上执行下面的命令查看

kubeadm token create --print-join-command

 

等待一段时间以后，docker把kube-proxy、flannel和pause的镜像都pull下来以后，回到master节点继续

 

k8s集群使用之前：

a：为新增的node节点添加角色

[root@k8s-master ~]# kubectl get nodes

NAME STATUS ROLES AGE VERSION

k8s-master Ready master 4h21m v1.13.3

k8s-node1 Ready <none> 77m v1.13.3

#这时我们发现新增的k8s-node1没有角色

 

给k8s-node1添加角色

kubectl label nodes k8s-node1 node-role.kubernetes.io/node=

再次查看

[root@k8s-master ~]# kubectl get nodes

NAME STATUS ROLES AGE VERSION

k8s-master Ready master 4h21m v1.13.3

k8s-node1 Ready node 77m v1.13.3

 

b：kubectl命令行自动补全

默认情况下kubectl命令不能补全，操作很不方便

添加kubectl自动补全方法：

source <(kubectl completion bash)

效果：

[root@k8s-master ~]# kubectl

annotate certificate create explain plugin set

api-resources cluster-info delete expose port-forward taint

api-versions completion describe get proxy top

apply config diff label replace uncordon

attach convert drain logs rollout version

auth cordon edit options run wait

autoscale cp exec patch scale

 

k8s集群运行一个nginx容器并被外界访问

kubectl create deployment nginx --image=nginx:1.14

kubectl expose deployment nginx --port=80 --type=NodePort

查看nginx的方法端口，从下图可以看出我的端口是30875

浏览器测试访问http://10.0.0.11:30875