20201201 kubernetes (一)

課堂資料

CentOS 7.6上安裝 Kubernetes（一）叢集佈署

Learn Kubernetes BasicsKubernetes

安裝 Kubernetes

所有機器安裝步驟

環境下加裝常用工具

yum install wget net-tools nano -y

vm1

vm2

vm3

為叢集設置主機名稱以便 nodes 間的相互溝通，XXX 分別對應自己的角色 Hostname

hostnamectl set-hostname XXX

vim /etc/hosts

vm1

vm2

vm3

禁用 Selinux 與 swap，

kubernetes 基於性能理由建議關閉 swap、更改 fstab 檔案註解 swap 分區以避免重開機後再次作用

setenforce 0

sed -i 's@SELINUX=enforcing@SELINUX=disabled@' /etc/sysconfig/selinux

vim /etc/fstab

vm1

註解swap只留下UUID

vm2

vm3

註解 swap 後須重新開機並使用free檢查swap是否關閉

ptables相關功能或模組的啟用與停用，後續kubernetes會接手管理這部分的網路功能

systemctl disable firewalld && systemctl stop firewalld

echo 1 > /proc/sys/net/ipv4/ip_forward

echo "net.ipv4.ip_forward = 1" >> /etc/sysctl.conf

echo "net.bridge.bridge-nf-call-iptables = 1" >> /etc/sysctl.conf

modprobe br_netfilter

echo "br_netfilter" > /etc/modules-load.d/br_netfilter.conf

sysctl -p

lsmod | grep br_netfilter

vm1

vm2

vm3

添加 docker-ce 與 kubernetes 的 yum 源、並重整 yum 倉庫

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

yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

vim /etc/yum.repos.d/kubernetes.repo

進入編輯後輸入以下文檔

[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg

vm1

vm2

vm3

yum clean all && yum repolist

vm1

vm2

vm3

安裝 docker-ce 與 kubernetes、指定套件的安裝版本並設置為開機啟動

yum install docker-ce-18.09.8 --nogpgcheck

systemctl enable docker && systemctl start docker

yum install kubelet-1.15.2 kubectl-1.15.2 kubeadm-1.15.2 --nogpgcheck --disableexcludes=kubernetes

systemctl enable kubelet.service

vm1

vm2

vm3

Master機器初始化：以vm1 為Master

初始化 master，api-server-advertise 指定為 master 的內部 IP，pod-network-cidr 與 service-cidr 都採預設值，也可以變更為其他

kubeadm init --apiserver-advertise-address=[ master IP ] --pod-network-cidr=10.244.0.0/16 --service-cidr=10.96.0.0/12 --kubernetes-version=v1.15.2 --cri-socket="/var/run/dockershim.sock"

紅字的前三行是在說明作為 master 角色還需手動輸入提示的指令，才能順利運作這個叢集，而最下方的kubeadm 範例則是提示 worker nodes 欲加入叢集所需輸入的指令

mkdir -p $HOME/.kube

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

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

安裝通用的 flannel容器網路介面CNI（Container Network Interface）元件

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

Then you can join any number of worker nodes by running the following on each as root：

kubeadm join 192.168.8.129:6443 --token e09bz5.lwdqen1ezp4wif1a \
    --discovery-token-ca-cert-hash sha256:982152b77b1cd7e7104d8cc15527020238c9654832c34014540c4f581cab34d0 

將結果複製去 vm2、vm3

vm2

vm3

cd k8s

kubectl get nodes

kubectl create deployment httpd-app --image=httpd

kubectl expose deployment httpd-app --type=NodePort --name=httpd-service --port=80

kubectl get svc

檢查是否連接：IP 位址:[ httpd-service's port(s) ]

vm1

vm2

vm3

初始化k8s

kubeadm reset

kubectl describe node [ master ]

kubectl get deployment

kubectl scale deployment httpd-app --replicas 2

kubectl get deployment

kubectl create deployment web1 --image=httpd

kubectl get deployment

kubectl describe deployment web1

kubectl create deployment web2 --image=http1d

kubectl get deployment

kubectl describe deployment web1

kubectl get pod

kubectl describe pod web2-d9b9cf459-flh2r

kubectl delete deployment web2

kubectl get deployment

kubectl get pod

kubectl get deployment

kubectl get deployment web1 -o yaml

kubectl get deployment web1 -o yaml > myweb.yml

gedit myweb.yml &

kubectl apply -f myweb.yml

kubectl get deployment

kubectl get pod

kubectl get pod -o wide

curl 10.244.1.3