ubuntu docker 加入k8s集群 ubuntu搭建k8s

Ubuntu18.04 安装K8S & 部署服务

• 一、实验题目
• 二、实验环境
• 三、实验步骤

• 3.1 系统配置更改
• 3.2 安装Docker
• 3.3 安装kubectl，kubelet，kubeadm
• 3.4 配置Master
• 3.5 配置Node

• 四、部署服务

• 4.1 命令模式
• 4.2 yaml模式

一、实验题目

题目二：用Kubernetes建立一个实验集群。支持pod的多个节点，在容器内部署了一个可访问的httpd示例服务。

二、实验环境

名称	版本
操作系统	Ubuntu 18.04 LTS
Docker	20.10.7, build f0df350
Kubernetes	v1.21.1

在VMware中设置三台主机，配置如下：

主机名	ipv4	节点
ubuntu-1	192.168.47.177	master
ubuntu-2	192.168.47.178	node-1
ubuntu-3	192.168.47.179	node-2

三、实验步骤

3.1 系统配置更改

1. 禁用swap

swapoff -a

1. 关闭防火墙

systemctl stop firewalld
systemctl disable firewalld

1. 配置静态IP

root@ubuntu-1:/home/zjy# vim /etc/netplan/00-installer-config.yaml 

# This is the network config written by 'subiquity'
network:
  ethernets:
    ens33:
      addresses: [192.168.47.177/24]
      dhcp4: false
      gateway4: 192.168.47.2
      nameservers:
              addresses: [192.168.47.2]
      optional: true
  version: 2

1. 将/etc/hosts配置如下

192.168.47.177 master
192.168.47.178 node-1
192.168.47.179 node-2

1. IP应⽤启动

netplan apply

1. 查看配置结果
   

3.2 安装Docker

1. 先安装相关工具

apt-get update && apt-get install -y apt-transport-https curl

1. 添加密钥

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add -

1. 使用官方安装脚本自动安装

curl -fsSL https://get.docker.com | bash -s docker --mirror Aliyun

1. 查看docker版本

root@ubuntu-1:/home/zjy# docker version
Client: Docker Engine - Community
 Version:           20.10.7
 API version:       1.41
 Go version:        go1.13.15
 Git commit:        f0df350
 Built:             Wed Jun  2 11:56:40 2021
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true

Server: Docker Engine - Community
 Engine:
  Version:          20.10.7
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.13.15
  Git commit:       b0f5bc3
  Built:            Wed Jun  2 11:54:48 2021
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.4.6
  GitCommit:        d71fcd7d8303cbf684402823e425e9dd2e99285d
 runc:
  Version:          1.0.0-rc95
  GitCommit:        b9ee9c6314599f1b4a7f497e1f1f856fe433d3b7
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

1. 启动docker service

systemctl enable docker
systemctl start docker
systemctl status docker

由于网络原因，我们在pull Image的时候，从Docker Hub上下载会很慢，使用阿里云加速器，修改文件：

vim  /etc/docker/daemon.json

{
    "registry-mirrors": ["https://alzgoonw.mirror.aliyuncs.com"],
    "live-restore": true
}

重启docker服务：

systemctl daemon-reload
systemctl restart docker

3.3 安装kubectl，kubelet，kubeadm

在Master和Node节点分别执行如下操作

1. 添加密钥

curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -

由于服务器无法访问国外网站，因此先在本地下载好apt-key.gpg文件，再拷贝到虚拟机上通过apt-key add apt-key.gpg来加载。

1. 添加Kubernetes软件源

cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb http://apt.kubernetes.io/ kubernetes-xenial main
EOF

上面是官方的源，国内不通需要修改为如下：

cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb http://mirrors.ustc.edu.cn/kubernetes/apt kubernetes-xenial main
EOF

1. 安装

sudo apt-get update
sudo apt-get install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl

apt-get update 错误超时，需要修改apt-get的源，采用ustc源：

vim /etc/apt/sources.list.d/kubernetes.list

# deb http://apt.kubernetes.io/ kubernetes-xenial main
deb http://mirrors.ustc.edu.cn/kubernetes/apt kubernetes-xenial main

执行完成后，终端显示结果如下：

3.4 配置Master

1. 增加环境变量
   在/etc/profile下面增加如下环境变量：

echo "export KUBECONFIG=/etc/kubernetes/admin.conf" >> ~/.bash_profile
# 生效
source ~/.bash_profile

# 重启 kubelet
systemctl daemon-reload
systemctl restart kubelet

1. 初始化 kubeadm
   在master节点上执行：

root@ubuntu-1:/home/zjy# kubeadm init --image-repository=registry.aliyuncs.com/google_containers --pod-network-cidr=10.244.0.0/16 --kubernetes-version=v1.21.1

• –pod-network-cidr是指配置节点中的pod的可用IP地址，此为内部IP
• –kubernetes-version 通过kubectl version 可以查看

结果如下：

1. 安装网络插件
   在安装完Master节点后，查看节点信息会发现节点的状态为 NotReady。

root@ubuntu-1:/home/zjy# kubectl get nodes

NAME       STATUS     ROLES                  AGE   VERSION
ubuntu-1   NotReady   control-plane,master   25m   v1.21.1

原因是由于CNI插件没有配置，即还没有配置网络，可以配置多种网络，这里选用最常用的Fannel网络进行配置。

root@ubuntu-1:/home/zjy# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

Warning: policy/v1beta1 PodSecurityPolicy is deprecated in v1.21+, unavailable in v1.25+
podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created

3.5 配置Node

1. 在各个node节点执行如下命令（对应master配置返回的 kubeadm join命令），加入master集群

root@ubuntu-2:/home/zjy# kubeadm join 192.168.47.177:6443 --token cnsmts.6w5gpiqxlqmhxnl0 --discovery-token-ca-cert-hash sha256:f90ca2cfc29707965cf35349e43945c32c2e4fe1db2cabd2183db9f9aef72f2d

[preflight] Running pre-flight checks
        [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the control-plane to see this node join the cluster.

1. 在master下查看nodes状态

四、部署服务

采用deployment方式部署 httpd 服务，这里采用 nginx。

4.1 命令模式

1. 命令如下：

kubectl create deployment nginx --image=nginx

1. 查看部署结果

该结果表明在当前集群上，已经成功自动地在 ubuntu-3（node-2） 节点上部署了一个 nginx 节点，并处于正常运行（running）的状态。

1. 互相通信
   根据给出的 Pod ipv4 地址，在 master 和 node 节点上对其进行 ping 通信，可见各个节点以及 Pod 已经可以互通，结果如下图：

1. 利用 curl 命令对其网页进行访问

root@ubuntu-1:/home/zjy# curl 10.244.2.2

1. 创建 service
   部署的 Pod 内服务还只能在集群内部命名空间下访问，无法被外部用户访问和请求。因此，我们继续在控制节点上创建 service，将服务暴露给外部访问。

root@ubuntu-1:/home/zjy# kubectl create service nodeport nginx --tcp 80:80
service/nginx created
root@ubuntu-1:/home/zjy# kubectl get svc

1. 外部访问
   在外部终端的浏览器中输入对应的地址和端口进行访问，可以看到此时外部用户也能访问到 nginx 的网页界面：

4.2 yaml模式

1. 创建 nginx-yaml.yaml 文件，内容如下：

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-yaml
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
        - name: nginx
          image: nginx:latest
          ports:
            - containerPort: 80

1. 从上述 yaml 文件创建新的deployment：

root@ubuntu-1:~# kubectl apply -f nginx-yaml.yaml
deployment.apps/nginx-yaml created

1. 查看具体信息

root@ubuntu-1:~#  kubectl describe deployment nginx-yaml
Name:                   nginx-yaml
Namespace:              default
CreationTimestamp:      Thu, 17 Jun 2021 15:31:31 +0000
Labels:                 <none>
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               app=nginx
Replicas:               2 desired | 2 updated | 2 total | 2 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:  app=nginx
  Containers:
   nginx:
    Image:        nginx:latest
    Port:         80/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   nginx-yaml-585449566 (2/2 replicas created)
Events:
  Type    Reason             Age   From                   Message
  ----    ------             ----  ----                   -------
  Normal  ScalingReplicaSet  5m8s  deployment-controller  Scaled up replica set nginx-yaml-585449566 to 2

1. 查看集群中的 pod 情况

root@ubuntu-1:~# kubectl get pods -o wide
NAME                              READY   STATUS    RESTARTS   AGE     IP           NODE       NOMINATED NODE   READINESS GATES
nginx-6799fc88d8-bkksv            1/1     Running   0          60m     10.244.2.2   ubuntu-3   <none>           <none>
nginx-yaml-585449566-6z487   1/1     Running   0          3m44s   10.244.2.5   ubuntu-3   <none>           <none>
nginx-yaml-585449566-g4fnn   1/1     Running   0          3m44s   10.244.2.6   ubuntu-3   <none>           <none>

1. 创建service

root@ubuntu-1:~# kubectl create service nodeport nginx --tcp 80:80

service/nginx created
root@ubuntu-1:~# kubectl get svc
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP        15m
nginx        NodePort    10.102.16.156   <none>        80:30831/TCP   5s

1. 外部访问