二、Kubernetes 环境搭建

2020-03-23 本文已影响0人 Suny____

1、Kubernetes 安装方式

Kubernetes 安装有很多种方式，有极其复杂的，也有相对复杂的，当然也有相对简单的，不过简单的是企业级的解决方案，是收费的，这里举几个例子来安装 Kubernetes！

The hard way
- 这是 最最最最复杂的，所有组件、环境都需要自己去搭建。
- 这里不演示，如果有兴趣，可以去Github上查看。
  - https://github.com/kelseyhightower/kubernetes-the-hard-way
the easiest way
- 这是最简单的了，就是利用官方提供的在线搭建方式
- 这里也不演示，跟着操作就好了
  - https://labs.play-with-k8s.com/
Cloud搭建解决方案 Kops
- https://github.com/kubernetes/kops
企业级解决方案 CoreOS
- https://coreos.com/tectonic/
Minikube
- 这是官方提供的一种安装方式，比较适合本地搭建k8s单节点，但是需要 科学上网
- https://kubernetes.io/docs/setup/learning-environment/minikube/
Kubeadm
- 这也是官方提供的安装方式，适合本地搭建 k8s 集群
  - 如果完全按照官方的操作，也还是需要 科学上网，但有办法绕过，后面演示在说
  - https://kubernetes.io/zh/docs/setup/independent/create-cluster-kubeadm/

本章只演示 Minikube 与 Kubeadm 两种安装方式

2、安装

2.1、Minikube 搭建方式

安装kubectl

根据官网步骤下载
- https://kubernetes.io/zh/docs/tasks/tools/
直接下载
kubectl&minikube 百度盘下载，提取码: pap8
配置 kubectl.exe 环境变量，使得cmd窗口可以直接使用kubectl命令

检查是否配置成功

kubectl version

C:\Users\32731>kubectl version
Client Version: version.Info{Major:"1", Minor:"16", GitVersion:"v1.16.2", GitCommit:"c97fe5036ef3df2967d086711e6c0c405941e14b", GitTreeState:"clean", BuildDate:"2019-10-15T19:18:23Z", GoVersion:"go1.12.10", Compiler:"gc", Platform:"windows/amd64"}

# k8s还没安装, 所以这里连不上
Unable to connect to the server: dial tcp [::1]:8080: connectex: No connection could be made because the target machine actively refused it.

安装minikube
- 根据官网步骤下载
  - https://kubernetes.io/zh/docs/tasks/tools/install-minikube/
- 直接下载
  - kubectl 的百度盘里都有
  - 从网盘下载的要改下名字
    - 修改minikube-windows-amd64.exe名称为minikube.exe
配置 minikube.exe 环境变量，使得cmd窗口可以直接使用minikube命令

检查是否配置成功

minikube version

C:\Users\32731>minikube version
minikube version: v1.5.2
commit: 792dbf92a1de583fcee76f8791cff12e0c9440ad-dirty

安装K8S

由于需要 科学上网，这里就不再继续演示了

# 指定VM驱动, 其实就是通过minikube创建一个虚拟机
C:\Users\32731>minikube start --vm-driver=virtualbox
! Microsoft Windows 10 Pro 10.0.17763 Build 17763 上的 minikube v1.5.2
* 正在下载 VM boot image...

常用命令

# 创建K8S
minikube start
# 删除K8S
minikube delete
# 进入到K8S的机器中
minikube ssh
# 查看状态
minikube status
# 进入dashboard
minikube dashboard

其他系统下使用Minikube的操作这里就不演示了,可以去官网上看

2.2、 Kubeadm 安装方式（无需科学上网）

官网安装 Kubeadm 步骤

2.2.1、准备环境

版本统一
- 这里采用旧版本，新版本据说有问题，我没去试过，就按下面的版本搭建
- Docker 18.09.0
- kubeadm-1.14.0-0
- kubelet-1.14.0-0
- kubectl-1.14.0-0
  - k8s.gcr.io/kube-apiserver:v1.14.0
  - k8s.gcr.io/kube-controller-manager:v1.14.0
  - k8s.gcr.io/kube-scheduler:v1.14.0
  - k8s.gcr.io/kube-proxy:v1.14.0
  - k8s.gcr.io/pause:3.1
  - k8s.gcr.io/etcd:3.3.10
  - k8s.gcr.io/coredns:1.3.1
- calico:v3.9
系统
- win10
虚拟化技术
- Virtual Box
- 采用vagrant + virtual box配合使用搭建centos7系统
配置要求
- 每台机器 2 GB 或更多的 RAM (如果少于这个数字将会影响您应用的运行内存)
- 2核 CPU 或更多
- 集群中的所有机器的网络彼此均能相互连接(公网和内网都可以)

vagrant安装方式

可以参考之前写的一、Docker环境准备

这里仅提供一次安装多个虚拟机的Vagrantfile

boxes = [
    {
        # 虚拟机名称
        :name => "master-kubeadm-k8s",
        # ip地址, 需要与win10的内网地址在同一个网段
        :eth1 => "192.168.50.111",
        # 分配2G内存
        :mem => "2048",
        # 分配2核CPU
        :cpu => "2",
        :sshport => 22230
    },
    {
        :name => "worker01-kubeadm-k8s",
        :eth1 => "192.168.50.112",
        :mem => "2048",
        :cpu => "2",
        :sshport => 22231
    },
    {
        :name => "worker02-kubeadm-k8s",
        :eth1 => "192.168.50.113",
        :mem => "2048",
        :cpu => "2",
        :sshport => 22232
    }
]
Vagrant.configure(2) do |config|
    config.vm.box = "centos/7"
    boxes.each do |opts|
        config.vm.define opts[:name] do |config|
            config.vm.hostname = opts[:name]
            config.vm.network :public_network, ip: opts[:eth1]
            config.vm.network "forwarded_port", guest: 22, host: 2222, id: "ssh", disabled: "true"
        config.vm.network "forwarded_port", guest: 22, host: opts[:sshport]
            config.vm.provider "vmware_fusion" do |v|
                v.vmx["memsize"] = opts[:mem]
                v.vmx["numvcpus"] = opts[:cpu]
            end
            config.vm.provider "virtualbox" do |v|
                v.customize ["modifyvm", :id, "--memory", opts[:mem]]
            v.customize ["modifyvm", :id, "--cpus", opts[:cpu]]
                v.customize ["modifyvm", :id, "--name", opts[:name]]
            end
        end
    end
end

安装效果

image.png

2.2.2、安装依赖，更改配置

更新 yum 源，3台虚拟机都要更新

yum -y update
yum install -y conntrack ipvsadm ipset jq sysstat curl iptables libseccomp

image.png

安装Docker

# 1、卸载之前安装的docker
sudo yum remove docker docker latest docker-latest-logrotate \
docker-logrotate docker-engine docker-client docker-client-latest docker-common

# 2、安装必要依赖
sudo yum install -y yum-utils device-mapper-persistent-data lvm2

# 3、设置docker仓库
sudo yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

# 4、设置阿里云镜像加速,这里的镜像地址大家可以去自己的阿里云镜像仓库复制,可能不一样
sudo mkdir -p /etc/docker
sudo tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://rrpa5ijo.mirror.aliyuncs.com"]
}
EOF
sudo systemctl daemon-reload

# 5、更新yum缓存
sudo yum makecache fast

# 6、安装 18.09.0版本 docker
sudo yum install -y docker-ce-18.09.0 docker-ce-cli-18.09.0 containerd.io

# 7、启动docker并设置开机启动
sudo systemctl start docker && sudo systemctl enable docker

# 8、测试docker安装是否成功
sudo docker run hello-world

修改 hosts文件，配置 hostname

# 1、设置master的hostname
[root@master-kubeadm-k8s ~]# sudo hostnamectl set-hostname master

# 2、设置worker01/02的hostname
[root@worker01-kubeadm-k8s ~]# sudo hostnamectl set-hostname worker01
[root@worker02-kubeadm-k8s ~]# sudo hostnamectl set-hostname worker02

# 3、修改3台机器的 hosts 文件
vi /etc/hosts

192.168.50.111 master
192.168.50.112 worker01
192.168.50.113 worker02

# 永久修改hostname,需要重启
sudo vi /etc/sysconfig/network
# 添加内容
hostname=master/worker01/worker02

# 4、在每台机器上 ping 测试一下，保证每台都可以 ping 通即可
[root@master-kubeadm-k8s ~]# ping worker01
PING worker01 (192.168.50.112) 56(84) bytes of data.
64 bytes from worker01 (192.168.50.112): icmp_seq=1 ttl=64 time=0.840 ms
64 bytes from worker01 (192.168.50.112): icmp_seq=2 ttl=64 time=0.792 ms
64 bytes from worker01 (192.168.50.112): icmp_seq=3 ttl=64 time=0.806 ms
.....

系统基础前提配置

# 1、关闭防火墙
systemctl stop firewalld && systemctl disable firewalld

# 2、关闭selinux
setenforce 0
sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

# 3、关闭swap
swapoff -a
sed -i '/swap/s/^\(.*\)$/#\1/g' /etc/fstab

# 4、配置iptables的ACCEPT规则
iptables -F && iptables -X && iptables -F -t nat && iptables -X -t nat && iptables -P FORWARD ACCEPT

# 5、设置系统参数
cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system

2.2.3、安装 Kubeadm、Kubelet 和 Kubectl

配置 yum 源

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

安装kubeadm、kubelet、kubectl

yum install -y kubeadm-1.14.0-0 kubelet-1.14.0-0 kubectl-1.14.0-0

docker和k8s设置同一个cgroup

# docker
vi /etc/docker/daemon.json
# 添加下面这个到首行,逗号别丢了
"exec-opts": ["native.cgroupdriver=systemd"],

# 重启docker，一定要执行
systemctl restart docker

# kubelet，这边如果发现输出 No such file or directory，说明是没问题的，继续往下进行即可
sed -i "s/cgroup-driver=systemd/cgroup-driver=cgroupfs/g" /etc/systemd/system/kubelet.service.d/10-kubeadm.conf

# 重启kubelet，一定要执行
systemctl enable kubelet && systemctl start kubelet

2.2.4、拉取 Kubeadm 必备的几个镜像

查看 kubeadm 使用的镜像

[root@master-kubeadm-k8s ~]# kubeadm config images list
...

# 这几个就是运行 Kubeadm 必备的几个镜像,但是都是国外镜像,没有科学上网不好直接拉取
k8s.gcr.io/kube-apiserver:v1.14.0
k8s.gcr.io/kube-controller-manager:v1.14.0
k8s.gcr.io/kube-scheduler:v1.14.0
k8s.gcr.io/kube-proxy:v1.14.0
k8s.gcr.io/pause:3.1
k8s.gcr.io/etcd:3.3.10
k8s.gcr.io/coredns:1.3.1

解决国外镜像不能访问的问题

可以通过国内镜像仓库下载所需镜像，然后修改镜像名称

创建 kubeadm.sh 脚本，用于拉取镜像、打tag、删除原有镜像

创建 kubeadm.sh 文件

#!/bin/bash
set -e
KUBE_VERSION=v1.14.0
KUBE_PAUSE_VERSION=3.1
ETCD_VERSION=3.3.10
CORE_DNS_VERSION=1.3.1
GCR_URL=k8s.gcr.io
ALIYUN_URL=registry.cn-hangzhou.aliyuncs.com/google_containers
images=(kube-proxy:${KUBE_VERSION}
kube-scheduler:${KUBE_VERSION}
kube-controller-manager:${KUBE_VERSION}
kube-apiserver:${KUBE_VERSION}
pause:${KUBE_PAUSE_VERSION}
etcd:${ETCD_VERSION}
coredns:${CORE_DNS_VERSION})

for imageName in ${images[@]} ; do
    docker pull $ALIYUN_URL/$imageName
    docker tag  $ALIYUN_URL/$imageName $GCR_URL/$imageName
    docker rmi $ALIYUN_URL/$imageName
done

运行脚本和查看镜像

# 运行脚本
sh ./kubeadm.sh

# 可以看到 Kubeadm 需要的镜像都下载好了
[root@master-kubeadm-k8s ~]# docker images
REPOSITORY                           TAG                 IMAGE ID            CREATED             SIZE
k8s.gcr.io/kube-proxy                v1.14.0             5cd54e388aba        12 months ago       82.1MB
k8s.gcr.io/kube-apiserver            v1.14.0             ecf910f40d6e        12 months ago       210MB
k8s.gcr.io/kube-controller-manager   v1.14.0             b95b1efa0436        12 months ago       158MB
k8s.gcr.io/kube-scheduler            v1.14.0             00638a24688b        12 months ago       81.6MB
k8s.gcr.io/coredns                   1.3.1               eb516548c180        14 months ago       40.3MB
hello-world                          latest              fce289e99eb9        14 months ago       1.84kB
k8s.gcr.io/etcd                      3.3.10              2c4adeb21b4f        15 months ago       258MB
k8s.gcr.io/pause                     3.1                 da86e6ba6ca1        2 years ago         742kB

2.2.5、kube init初始化master

初始化master节点

官网步骤
注意：此操作是在 Master 节点上进行

# 若要重新初始化集群状态：kubeadm reset，然后再进行 init 操作
# 指定 Kubernetes 的版本，指定主节点的 ip，指定网段的ip（可以不不指定）
kubeadm init --kubernetes-version=1.14.0 --apiserver-advertise-address=192.168.50.111 --pod-network-cidr=10.244.0.0/16

# 执行 init 完成后给出的提示
Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

# ================根据下面的提示继续再主节点执行========================
  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 这里要先自己保存好，后面操作 worker节点要用它来加入集群
kubeadm join 192.168.50.111:6443 --token se5kqz.roc626v5x1jzv2mp \
    --discovery-token-ca-cert-hash sha256:de8685c390d0f2addsdf86468fea9e02622705fb5eed84daa5b5ca667df29dff

执行完上面的 3 个命令后查看pod验证一下

[root@master-kubeadm-k8s ~]# kubectl get pods -n kube-system
NAME                                         READY   STATUS    RESTARTS   AGE
coredns-fb8b8dccf-gwqj9                      0/1     Pending   0          4m55s
coredns-fb8b8dccf-lj92j                      0/1     Pending   0          4m55s
etcd-master-kubeadm-k8s                      1/1     Running   0          4m13s
kube-apiserver-master-kubeadm-k8s            1/1     Running   0          4m2s
kube-controller-manager-master-kubeadm-k8s   1/1     Running   0          3m59s
kube-proxy-hhnmc                             1/1     Running   0          4m55s
kube-scheduler-master-kubeadm-k8s            1/1     Running   0          4m24s

注意：coredns没有启动，是因为还需要安装网络插件

健康检查

[root@master-kubeadm-k8s ~]# curl -k https://localhost:6443/healthz

kubeadm init流程

不需要执行，这里只是说明 Kubeadm init的流程

# 1、进行一系列检查，以确定这台机器可以部署kubernetes
# 2、生成kubernetes对外提供服务所需要的各种证书可对应目录
ls /etc/kubernetes/pki/*

# 3、为其他组件生成访问kube-ApiServer所需的配置文件
ls /etc/kubernetes/
    
    # admin.conf 
    # controller-manager.conf 
    # kubelet.conf 
    # scheduler.conf
    
# 4、为 Master组件生成Pod配置文件。
ls /etc/kubernetes/manifests/*.yaml

    # kube-apiserver.yaml 
    # kube-controller-manager.yaml
    # kube-scheduler.yaml
    
# 5、生成etcd的Pod YAML文件。
ls /etc/kubernetes/manifests/*.yaml

    # kube-apiserver.yaml 
    # kube-controller-manager.yaml
    # kube-scheduler.yaml
    # etcd.yaml
    
# 6、一旦这些 YAML 文件出现在被 kubelet 监视的/etc/kubernetes/manifests/目录下，kubelet就会自动创建这些yaml文件定义的pod，即master组件的容器。master容器启动后，kubeadm会通过检查localhost：6443/healthz这个master组件的健康状态检查URL，等待master组件完全运行起来

# 7、为集群生成一个bootstrap token

# 8、将ca.crt等 Master节点的重要信息，通过ConfigMap的方式保存在etcd中，工后续部署node节点使用

# 9、最后一步是安装默认插件，kubernetes默认kube-proxy和DNS两个插件是必须安装的

部署calico网络插件

选择网络插件
- 可以选择不同的网络插件，这里就以calico插件演示
calico网络插件

# 同样在master节点上操作

# 如果网速够快的话,可以直接安装calico,不需要单独去拉取镜像,这里只是把步骤单独提取出来执行了
# 可以先手动拉取 calico 的 yml 文件,查看需要哪些镜像
[root@master-kubeadm-k8s ~]# curl https://docs.projectcalico.org/v3.9/manifests/calico.yaml | grep image
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0 20674    0     0    0     0      0      0 --:--:--  0:00:05 --:--:--     0 
100 20674  100 20674    0     0   3216      0  0:00:06  0:00:06 --:--:--  4955

        # 版本会变化，需要根据实际情况拉取镜像
          image: calico/cni:v3.9.5
          image: calico/pod2daemon-flexvol:v3.9.5
          image: calico/node:v3.9.5
          image: calico/kube-controllers:v3.9.5

# 拉取 calico 所需镜像, 可能会比较慢
[root@master-kubeadm-k8s ~]# docker pull calico/cni:v3.9.5
[root@master-kubeadm-k8s ~]# docker pull calico/pod2daemon-flexvol:v3.9.5
[root@master-kubeadm-k8s ~]# docker pull calico/node:v3.9.5
[root@master-kubeadm-k8s ~]# docker pull calico/kube-controllers:v3.9.5

# 安装 calico
[root@master-kubeadm-k8s ~]# kubectl apply -f https://docs.projectcalico.org/v3.9/manifests/calico.yaml

# -w 监控所有的Pods的状态变化
[root@master-kubeadm-k8s ~]# kubectl get pods --all-namespaces -w

不动的话取消重新执行,当所有 pod 的状态都是 Running 表示完成

image.png

2.2.6、worker节点加入集群

kube join

复制之前保存的初始化master节点时最后打印的 Kubeadm Join 信息到worker节点执行

# worker01 节点
[root@worker01-kubeadm-k8s ~]# kubeadm join 192.168.50.111:6443 --token se5kqz.roc626v5x1jzv2mp \
>     --discovery-token-ca-cert-hash sha256:de8685c390d0f2addsdf86468fea9e02622705fb5eed84daa5b5ca667df29dff
[preflight] Running pre-flight checks
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.14" ConfigMap in the kube-system namespace
[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] Activating the kubelet service
[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.

# worker02 节点
[root@worker02-kubeadm-k8s ~]# kubeadm join 192.168.50.111:6443 --token se5kqz.roc626v5x1jzv2mp \
>     --discovery-token-ca-cert-hash sha256:de8685c390d0f2addsdf86468fea9e02622705fb5eed84daa5b5ca667df29dff
[preflight] Running pre-flight checks
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.14" ConfigMap in the kube-system namespace
[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] Activating the kubelet service
[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.

检查集群信息

#在 Master 节点执行
[root@master-kubeadm-k8s ~]# kubectl get nodes
NAME                   STATUS     ROLES    AGE   VERSION
master-kubeadm-k8s     Ready      master   37m   v1.14.0
# 这里还是 NotReady, 等待完成即可
worker01-kubeadm-k8s   NotReady   <none>   84s   v1.14.0
worker02-kubeadm-k8s   NotReady   <none>   79s   v1.14.0

# 等一会再次执行,可以看到所有节点都是 Ready 状态, 表示集群已经搭建完成了!
[root@master-kubeadm-k8s ~]# kubectl get nodes
NAME                   STATUS   ROLES    AGE     VERSION
master-kubeadm-k8s     Ready    master   40m     v1.14.0
worker01-kubeadm-k8s   Ready    <none>   3m48s   v1.14.0
worker02-kubeadm-k8s   Ready    <none>   3m43s   v1.14.0

2.3、初体验 Pod

定义 pod.yml 文件

建立文件夹

[root@master-kubeadm-k8s ~]# mkdir pod_nginx_rs
[root@master-kubeadm-k8s ~]# cd pod_nginx_rs/

编写 yml 文件

# 编写 yml 文件, yml、yaml都可以识别
cat > pod_nginx_rs.yaml <<EOF
apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: nginx
  labels:
    tier: frontend
spec:
  replicas: 3
  selector:
    matchLabels:
      tier: frontend
  template:
    metadata:
      name: nginx
      labels:
        tier: frontend
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
EOF

根据pod_nginx_rs.yml文件创建pod

[root@master-kubeadm-k8s pod_nginx_rs]# kubectl apply -f pod_nginx_rs.yaml
replicaset.apps/nginx created

查看 Pod

kubectl get pods

# 现在还没有准备好,等会可以再次执行查看
[root@master-kubeadm-k8s pod_nginx_rs]# kubectl get pods
NAME          READY   STATUS              RESTARTS   AGE
nginx-hdz6w   0/1     ContainerCreating   0          27s
nginx-kbqxx   0/1     ContainerCreating   0          27s
nginx-xtttc   0/1     ContainerCreating   0          27s

# 已经完成了
[root@master-kubeadm-k8s pod_nginx_rs]# kubectl get pods
NAME          READY   STATUS    RESTARTS   AGE
nginx-hdz6w   1/1     Running   0          3m10s
nginx-kbqxx   1/1     Running   0          3m10s
nginx-xtttc   1/1     Running   0          3m10s

kubectl get pods -o wide

# 查看 pods 详情,可以看到 worker01 节点有两个 pod, worker02 有一个 pod
# 注意: 这里面的 IP 是网络插件帮助生成的, 并不是指 宿主机的IP
[root@master-kubeadm-k8s pod_nginx_rs]# kubectl get pods -o wide
NAME          READY   STATUS    RESTARTS   AGE     IP               NODE                   NOMINATED NODE   READINESS GATES
nginx-hdz6w   1/1     Running   0          3m26s   192.168.14.2     worker01-kubeadm-k8s   <none>           <none>
nginx-kbqxx   1/1     Running   0          3m26s   192.168.221.65   worker02-kubeadm-k8s   <none>           <none>
nginx-xtttc   1/1     Running   0          3m26s   192.168.14.1     worker01-kubeadm-k8s   <none>           <none>

# worker01 是有 2 个Nginx的, 下面的 pause 是不算的,原因后面章节再解释
[root@worker01-kubeadm-k8s ~]# docker ps | grep nginx
acf671c4b9e5        nginx                  "nginx -g 'daemon of…"   3 minutes ago       Up 3 minutes 
4109bd09f0a1        nginx                  "nginx -g 'daemon of…"   4 minutes ago       Up 4 minutes 
3e5dcc552287        k8s.gcr.io/pause:3.1   "/pause"                 6 minutes ago       Up 6 minutes 
9e0d36cb813c        k8s.gcr.io/pause:3.1   "/pause"                 6 minutes ago       Up 6 minutes

# worker02 只有一个 Nginx
[root@worker02-kubeadm-k8s ~]# docker ps | grep nginx
c490e8d291d3        nginx                  "nginx -g 'daemon of…"   6 minutes ago       Up 6 minutes
b5ab5b408063        k8s.gcr.io/pause:3.1   "/pause"                 8 minutes ago       Up 8 minutes

kubectl describe pod nginx

# 查看 pod 的详情描述,包含了创建过程、yml文件内容、镜像拉取信息等等。。。。
[root@master-kubeadm-k8s pod_nginx_rs]# kubectl describe pod nginx
Name:               nginx-hdz6w
Namespace:          default
Priority:           0
PriorityClassName:  <none>
Node:               worker01-kubeadm-k8s/10.0.2.15
Start Time:         Tue, 24 Mar 2020 15:14:43 +0000
Labels:             tier=frontend
Annotations:        cni.projectcalico.org/podIP: 192.168.14.2/32
Status:             Running
IP:                 192.168.14.2
Controlled By:      ReplicaSet/nginx
Containers:
  nginx:
    Container ID:   docker://4109bd09f0a11c0de77f411258e2cd18cc7ea624ad733a2e9c16f6468aadd448
    Image:          nginx
    Image ID:       docker-pullable://nginx@sha256:2539d4344dd18e1df02be842ffc435f8e1f699cfc55516e2cf2cb16b7a9aea0b
    Port:           80/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Tue, 24 Mar 2020 15:16:21 +0000
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-xggf5 (ro)
Conditions:
  Type              Status
  Initialized       True
  Ready             True
  ContainersReady   True
  PodScheduled      True
Volumes:
  default-token-xggf5:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-xggf5
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type    Reason     Age    From                           Message
  ----    ------     ----   ----                           -------
  Normal  Scheduled  3m56s  default-scheduler              Successfully assigned default/nginx-hdz6w to worker01-kubeadm-k8s
  Normal  Pulling    3m52s  kubelet, worker01-kubeadm-k8s  Pulling image "nginx"
  Normal  Pulled     2m20s  kubelet, worker01-kubeadm-k8s  Successfully pulled image "nginx"
  Normal  Created    2m18s  kubelet, worker01-kubeadm-k8s  Created container nginx
  Normal  Started    2m18s  kubelet, worker01-kubeadm-k8s  Started container nginx

pod 扩容

# 将 nginx 扩容为 5 个 pod
[root@master-kubeadm-k8s pod_nginx_rs]# kubectl scale rs nginx --replicas=5
replicaset.extensions/nginx scaled

# 查看 pod, 新增的 2个 pod 正在创建
[root@master-kubeadm-k8s pod_nginx_rs]# kubectl get pods -o wide
NAME          READY   STATUS              RESTARTS   AGE   IP               NODE                   NOMINATED NODE   READINESS GATES
nginx-7xf8m   0/1     ContainerCreating   0          5s    <none>           worker01-kubeadm-k8s   <none>           <none>
nginx-hdz6w   1/1     Running             0          14m   192.168.14.2     worker01-kubeadm-k8s   <none>           <none>
nginx-kbqxx   1/1     Running             0          14m   192.168.221.65   worker02-kubeadm-k8s   <none>           <none>
nginx-qw2dh   0/1     ContainerCreating   0          5s    <none>           worker02-kubeadm-k8s   <none>           <none>
nginx-xtttc   1/1     Running             0          14m   192.168.14.1     worker01-kubeadm-k8s   <none>           <none>

测试

[root@master-kubeadm-k8s pod_nginx_rs]# ping 192.168.14.2
PING 192.168.14.2 (192.168.14.2) 56(84) bytes of data.
64 bytes from 192.168.14.2: icmp_seq=1 ttl=63 time=1.64 ms
64 bytes from 192.168.14.2: icmp_seq=2 ttl=63 time=1.03 ms
^C
--- 192.168.14.2 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1002ms
rtt min/avg/max/mdev = 1.033/1.337/1.641/0.304 ms

# 访问任意 pod 的IP,访问成功
[root@master-kubeadm-k8s pod_nginx_rs]# curl 192.168.14.2
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

删除 pod

[root@master-kubeadm-k8s pod_nginx_rs]# kubectl delete -f pod_nginx_rs.yaml
replicaset.apps "nginx" deleted

二、Kubernetes 环境搭建

1、Kubernetes 安装方式

2、安装

2.1、Minikube 搭建方式

2.2、 Kubeadm 安装方式（无需科学上网）

2.2.1、准备环境

2.2.2、安装依赖，更改配置

2.2.3、安装 Kubeadm、Kubelet 和 Kubectl

2.2.4、拉取 Kubeadm 必备的几个镜像

2.2.5、kube init初始化master

2.2.6、worker节点加入集群

2.3、初体验 Pod

Kubernetes 集群搭建已经全部完成，Kubeadm 方式搭建还是比较麻烦的，如果公司有需要搭建 K8S 集群，也是完全可以通过这种方式来搭建的！

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