CentOS7安装Kubernetes1.16.3
- 2020 年 3 月 9 日
- 筆記
一、概述
手工搭建 Kubernetes 集群是一件很繁琐的事情，为了简化这些操作，就产生了很多安装配置工具，如 Kubeadm ，Kubespray，RKE 等组件，我最终选择了官方的 Kubeadm 主要是不同的 Kubernetes 版本都有一些差异，Kubeadm 更新与支持的会好一些。Kubeadm 是 Kubernetes 官方提供的快速安装和初始化 Kubernetes 集群的工具，目前的还处于孵化开发状态，跟随 Kubernetes 每个新版本的发布都会同步更新, 强烈建议先看下官方的文档了解下各个组件与对象的作用。
https://kubernetes.io/docs/concepts/ https://kubernetes.io/docs/setup/independent/install-kubeadm/ https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm/
系统环境
|
系统 |
内核 |
docker |
ip |
主机名 |
配置 |
|---|---|---|---|---|---|
|
centos 7.6 |
3.10.0-957.el7.x86_64 |
19.03.5 |
192.168.31.150 |
k8s-master |
2核4G |
|
centos 7.6 |
3.10.0-957.el7.x86_64 |
19.03.5 |
192.168.31.183 |
k8s-node01 |
2核4G |
注意：请确保CPU至少2核，内存2G
二、准备工作
关闭防火墙
如果各个主机启用了防火墙，需要开放Kubernetes各个组件所需要的端口，可以查看Installing kubeadm中的”Check required ports”一节。 这里简单起见在各节点禁用防火墙：
systemctl stop firewalld systemctl disable firewalld
禁用SELINUX
# 临时禁用 setenforce 0# 永久禁用 vim /etc/selinux/config # 或者修改/etc/sysconfig/selinux SELINUX=disabled
修改k8s.conf文件
cat <<EOF > /etc/sysctl.d/k8s.conf net.bridge.bridge-nf-call-ip6tables = 1 net.bridge.bridge-nf-call-iptables = 1 EOF sysctl --system
关闭swap
# 临时关闭 swapoff -a
修改 /etc/fstab 文件，注释掉 SWAP 的自动挂载（永久关闭swap，重启后生效）
# 注释掉以下字段 /dev/mapper/cl-swap swap swap defaults 0 0
安装docker
这里就不再叙述了，请参考链接：
https://www.cnblogs.com/xiao987334176/p/11771657.html
修改主机名
hostnamectl set-hostname k8s-master
注意：主机名不能带下划线，只能带中划线 否则安装k8s会报错
could not convert cfg to an internal cfg: nodeRegistration.name: Invalid value: "k8s_master": a DNS-1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*')
三、安装kubeadm，kubelet，kubectl
在各节点安装kubeadm，kubelet，kubectl
修改yum安装源
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
安装软件
目前最新版本是：1.16.3
yum install -y kubelet-1.16.3-0 kubeadm-1.16.3-0 kubectl-1.16.3-0 systemctl enable kubelet && systemctl start kubelet
以上，就是master和node都需要操作的部分。
四、初始化Master节点
运行初始化命令
kubeadm init --kubernetes-version=1.16.3 --apiserver-advertise-address=192.168.31.150 --image-repository registry.aliyuncs.com/google_containers --service-cidr=10.1.0.0/16 --pod-network-cidr=10.244.0.0/16
参数解释：
–kubernetes-version: 用于指定k8s版本； –apiserver-advertise-address：用于指定kube-apiserver监听的ip地址,就是 master本机IP地址。 –pod-network-cidr：用于指定Pod的网络范围； 10.244.0.0/16–service-cidr：用于指定SVC的网络范围； –image-repository: 指定阿里云镜像仓库地址
这一步很关键，由于kubeadm 默认从官网k8s.grc.io下载所需镜像，国内无法访问，因此需要通过–image-repository指定阿里云镜像仓库地址
集群初始化成功后返回如下信息： 记录生成的最后部分内容，此内容需要在其它节点加入Kubernetes集群时执行。 输出如下：
... Your Kubernetes control-plane 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/Then you can join any number of worker nodes by running the following on each as root: kubeadm join 192.168.31.150:6443 --token ute1qr.ylhan3tn3eohip20 --discovery-token-ca-cert-hash sha256:f7b37ecd602deb59e0ddc2a0cfa842f8c3950690f43a5d552a7cefef37d1fa31
配置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
安装Calico
mkdir k8s cd k8s wget https://docs.projectcalico.org/v3.10/getting-started/kubernetes/installation/hosted/kubernetes-datastore/calico-networking/1.7/calico.yaml ## 将192.168.0.0/16修改ip地址为10.244.0.0/16 sed -i 's/192.168.0.0/10.244.0.0/g' calico.yaml
加载Calico
kubectl apply -f calico.yaml
查看Pod状态
等待几分钟，确保所有的Pod都处于Running状态
[root@k8s_master k8s]# kubectl get pod --all-namespaces -o wide NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATESkube-system calico-kube-controllers-6b64bcd855-tdv2h 1/1 Running 0 2m37s 192.168.235.195 k8s-master <none> <none>kube-system calico-node-4xgk8 1/1 Running 0 2m38s 192.168.31.150 k8s-master <none> <none>kube-system coredns-58cc8c89f4-8672x 1/1 Running 0 45m 192.168.235.194 k8s-master <none> <none>kube-system coredns-58cc8c89f4-8h8tq 1/1 Running 0 45m 192.168.235.193 k8s-master <none> <none>kube-system etcd-k8s-master 1/1 Running 0 44m 192.168.31.150 k8s-master <none> <none>kube-system kube-apiserver-k8s-master 1/1 Running 0 44m 192.168.31.150 k8s-master <none> <none>kube-system kube-controller-manager-k8s-master 1/1 Running 0 44m 192.168.31.150 k8s-master <none> <none>kube-system kube-proxy-6f42j 1/1 Running 0 45m 192.168.31.150 k8s-master <none> <none>kube-system kube-scheduler-k8s-master 1/1 Running 0 44m 192.168.31.150 k8s-master <none> <none>
注意：calico-kube-controllers容器的网段不是10.244.0.0/16
删除Calico，重新加载
kubectl apply -f calico.yaml kubectl delete -f calico.yaml
再次查看ip
[root@k8s-master k8s]# kubectl get pod --all-namespaces -o wide NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATESkube-system calico-kube-controllers-6b64bcd855-qn6bs 0/1 Running 0 18s 10.244.235.193 k8s-master <none> <none>kube-system calico-node-cdnvz 1/1 Running 0 18s 192.168.31.150 k8s-master <none> <none>kube-system coredns-58cc8c89f4-8672x 1/1 Running 1 5h22m 192.168.235.197 k8s-master <none> <none>kube-system coredns-58cc8c89f4-8h8tq 1/1 Running 1 5h22m 192.168.235.196 k8s-master <none> <none>kube-system etcd-k8s-master 1/1 Running 1 5h22m 192.168.31.150 k8s-master <none> <none>kube-system kube-apiserver-k8s-master 1/1 Running 1 5h21m 192.168.31.150 k8s-master <none> <none>kube-system kube-controller-manager-k8s-master 1/1 Running 1 5h22m 192.168.31.150 k8s-master <none> <none>kube-system kube-proxy-6f42j 1/1 Running 1 5h22m 192.168.31.150 k8s-master <none> <none>kube-system kube-scheduler-k8s-master 1/1 Running 1 5h21m 192.168.31.150 k8s-master <none> <none>
发现，ip地址已经是10.244.0.0/16 网段了。
设置开机启动
systemctl enable kubelet
五、node加入集群
准备工作
请查看上文中的准备工作，确保都执行了！！！
修改主机名部分，改为k8s-node01
hostnamectl set-hostname k8s-node01
加入节点
登录到node节点，确保已经安装了docker和kubeadm，kubelet，kubectl
kubeadm join 192.168.31.150:6443 --token ute1qr.ylhan3tn3eohip20 --discovery-token-ca-cert-hash sha256:f7b37ecd602deb59e0ddc2a0cfa842f8c3950690f43a5d552a7cefef37d1fa31
设置开机启动
systemctl enable kubelet
查看节点
登录到master，使用命令查看
[root@k8s_master k8s]# kubectl get nodes -o wide NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME k8s-master Ready master 87m v1.16.3 192.168.31.150 <none> CentOS Linux 7 (Core) 3.10.0-957.el7.x86_64 docker://19.3.5k8s-node01 Ready <none> 5m14s v1.16.3 192.168.31.183 <none> CentOS Linux 7 (Core) 3.10.0-957.el7.x86_64 docker://19.3.5
六、创建Pod
创建nginx
kubectl create deployment nginx --image=--port= --type=
查看pod和svc
[root@k8s-master k8s]# kubectl get pod,svc -o wide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES pod/nginx-86c57db685-z2kdd 1/1 Running 0 18m 10.244.85.194 k8s-node01 <none> <none>NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR service/kubernetes ClusterIP 10.1.0.1 <none> 443/TCP 111m <none>service/nginx NodePort 10.1.111.179 <none> 80:30876/TCP 24m app=nginx
允许外网访问nodePort
iptables -P FORWARD ACCEPT
测试访问
使用master ip+nodeport端口方式访问
http://192.168.31.150:30876/
效果如下：
命令补全
（仅master）
yum install -y bash-completion source <(kubectl completion bash) echo "source <(kubectl completion bash)" >> ~/.bashrc source ~/.bashrc
必须退出一次，再次登录，就可以了
七、使用yml发布应用
以flaskapp为例子
flaskapp-deployment.yaml
apiVersion: apps/v1 kind: Deployment metadata: name: flaskapp-1 spec: selector: matchLabels: run: flaskapp-1 replicas: 1 template: metadata: labels: run: flaskapp-1 spec: containers: - name: flaskapp-1 image: jcdemo/flaskapp ports: - containerPort: 5000
flaskapp-service.yaml
apiVersion: v1 kind: Service metadata: name: flaskapp-1 labels: run: flaskapp-1 spec: type: NodePort ports: - port: 5000 name: flaskapp-port targetPort: 5000 protocol: TCP nodePort: 30005 selector: run: flaskapp-1
加载yml文件
kubectl apply -f flaskapp-service.yaml kubectl apply -f flaskapp-deployment.yaml
访问页面
使用master ip+nodeport访问
http://192.168.31.183:30005/
效果如下：
注意：使用node节点ip+nodeport也可以访问。
本文参考链接： https://yq.aliyun.com/articles/626118 https://blog.csdn.net/fenglailea/article/details/88745642
