搭建K8s集群

资源准备

准备3台虚拟机

先安装docker

再安装k8s

安装版本

• Docker 18.09.0
• calico:v3.22.1
• kubeadm-1.23.5
• kubelet-1.23.5
• kubectl-1.23.5

• k8s.gcr.io/kube-apiserver:v1.23.5
• k8s.gcr.io/kube-controller-manager:v1.23.5
• k8s.gcr.io/kube-scheduler:v1.23.5
• k8s.gcr.io/kube-proxy:v1.23.5
• k8s.gcr.io/pause:3.6
• k8s.gcr.io/etcd:3.5.1-0
• k8s.gcr.io/coredns/coredns:v1.8.6

环境搭建

1.创建 Vagrantfile 文件

备注：10.13.11.21 修改成当前所属网段

boxes = [
  {
    :name => "master-kubeadm-k8s",
    :eth1 => "10.13.11.21",
    :mem => "2048",
    :cpu => "2",
    :sshport => 22230
  },
  {
    :name => "worker01-kubeadm-k8s",
    :eth1 => "10.13.11.22",
    :mem => "2048",
    :cpu => "2",
    :sshport => 22231
  },
  {
    :name => "worker02-kubeadm-k8s",
    :eth1 => "10.13.11.23",
    :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

2.启动，并进入到三台虚拟机中

#[启动虚拟机]
vagrant up 
#[进入manager-node]
vagrant ssh master-kubeadm-k8s 
#[进入worker01-node]
vagrant ssh worker01-kubeadm-k8s 
#[进入worker02-node]
vagrant ssh worker02-kubeadm-k8s

3.修改成可以密码登陆root账户(3台机器同时操作)

#[进入root账户]
sudo -i 
#[设置root账户可以密码登陆]
vi /etc/ssh/sshd_config 
#修改 PasswordAuthentication yes
PasswordAuthentication yes
#[修改密码]
passwd 
#[重启sshd服务]
systemctl restart sshd

4.更新并安装依赖（3台机器都要操作）

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

安装Docker（3台机器都要操作）

#01 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
#02 安装必要依赖
    sudo yum install -y yum-utils device-mapper-persistent-data lvm2
#03 添加软件源信息
    sudo yum-config-manager \
    --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
#04 更新yum缓存
    sudo yum makecache fast
#05 安装docker [指定安装docker版本]
    udo yum install -y docker-ce-18.09.0 docker-ce-cli-18.09.0 containerd.io 
#06 `启动docker并设置开机启动
    sudo systemctl start docker && sudo systemctl enable docker
#07 测试docker安装是否成功
    sudo docker run hello-world

修改hosts文件

1.设置master的hostname

sudo hostnamectl set-hostname m

2.设置worker01的hostname

sudo hostnamectl set-hostname w1

3.设置worker02的hostname

sudo hostnamectl set-hostname w

4.修改hosts文件（3台机器同时操作）

vi /etc/hosts

10.13.11.21 m
10.13.11.22 w1
10.13.11.23 w2

5.测试是否ping通

ping m
ping w1
ping w2

系统基础前提配置(3台机器都要操作)

#01 关闭防火墙
    systemctl stop firewalld && systemctl disable firewalld
#02 关闭selinux
    setenforce 0
    sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config
#03 关闭swap
    swapoff -a
    sed -i '/swap/s/^\(.*\)$/#\1/g' /etc/fstab
#04 配置iptables的ACCEPT规则
    iptables -F && iptables -X && iptables \
    -F -t nat && iptables -X -t nat && iptables -P FORWARD ACCEPT
#05 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

安装 kubeadm, kubelet and kubectl(3台机器都要操作)

1.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

2.安装kubeadm&kubelet&kubectl

yum install -y kubeadm-1.23.5-0 kubelet-1.23.5-0 kubectl-1.23.5-0

3.docker和k8s设置同一个cgroup

#文件没内容的话，就新建；有的话，就加上这一句，注意文件的格式[逗号]
vi /etc/docker/daemon.json

{
  "exec-opts": ["native.cgroupdriver=systemd"]
}

#【`重启docker，一定要执行`】
systemctl restart docker 

#【`找不到内容没关系`】
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

proxy/pause/scheduler等国内镜像(3台机器都要操作)

1.查看kubeadm使用的镜像

kubeadm config images list
#############################得到结果######################
k8s.gcr.io/kube-apiserver:v1.23.5
k8s.gcr.io/kube-controller-manager:v1.23.5
k8s.gcr.io/kube-scheduler:v1.23.5
k8s.gcr.io/kube-proxy:v1.23.5
k8s.gcr.io/pause:3.6
k8s.gcr.io/etcd:3.5.1-0
k8s.gcr.io/coredns/coredns:v1.8.6
#############################得到结果######################

解决国外镜像不能访问的问题

#创建kubeadm.sh脚本，用于拉取镜像/打tag/删除原有镜像
vi kubeadm.sh

#!/bin/bash
set -e
KUBE_VERSION=v1.23.5
KUBE_PAUSE_VERSION=3.6
ETCD_VERSION=3.5.1-0
CORE_DNS_VERSION=v1.8.6
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
sh ./kubeadm.sh
#【查看镜像】
docker images

kube init初始化master

初始化master节点（两个从节点不用执行）

#01【初始化集群状态】
kubeadm reset 
#02【初始化master节点】，10.13.11.21 为主节点ip，根据自己更改
kubeadm init --kubernetes-version=v1.23.5 \
--apiserver-advertise-address=10.13.11.21 \
--pod-network-cidr=10.244.0.0/16 
#03 注意：记得保存好最后kubeadm join的信息。
#############################得到结果######################
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
Alternatively, if you are the root user, you can run:
export KUBECONFIG=/etc/kubernetes/admin.conf
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 192.168.31.91:6443 --token z7xmcd.sgza584qba9tl6nh \
--discovery-token-ca-cert-hash sha256:c94894c5b14693b37f62297a2a6906cfe807d80cfadfc503a6edda91114d818a
#############################得到结果######################

#04 根据日志提示执行
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config


#05 查看pod
#【查看kube-system的pods】
kubectl get pods -n kube-system 
#【查看所有pods】
kubectl get pods --all-namespaces 

#06 健康检查
curl -k https://localhost:6443/healthz
#############################得到结果######################
[root@master-kubeadm-k8s ~]# curl -k https://localhost:6443/healthz
ok
#############################得到结果######################

kube init流程（只需要了解即可）

01-进行一系列检查，以确定这台机器可以部署kubernetes

02-生成kubernetes对外提供服务所需要的各种证书可对应目录
/etc/kubernetes/pki/*

03-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
    
04-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
    
05-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
    
06-一旦这些 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

07-为集群生成一个bootstrap token

08-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

09-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

wget https://docs.projectcalico.org/manifests/calico.yaml

kubectl apply -f calico.yaml

#也可以提现下载好，具体版本号可以在calico.yaml 中找到对应，再下载
docker pull calico/cni:v3.22.1
docker pull calico/pod2daemon-flexvol:v3.22.1
docker pull calico/node:v3.22.1
docker pull calico/kube-controllers:v3.22.1


#确认一下calico是否安装成功,【实时查看所有的Pods】
kubectl get pods --all-namespaces -w

kube join

#01 记得保存初始化master节点的最后打印信息【注意这边大家要自己的，下面我的只是一个参考】
#【worker上面执行】在两个从节点执行！！！
    kubeadm join 10.13.11.21:6443 --token fag134.3wot9edrvs82vh6d \
    --discovery-token-ca-cert-hash sha256:1df02a06552c02ba0e28e00c80a50e9ff40da81a4cdd53c136a16d3c0233f450    

#02 在master节点上检查集群信息
    kubectl get nodes
# =======================================================================================
NAME                   STATUS   ROLES    AGE     VERSION
master-kubeadm-k8s     Ready    master   19m     v1.14.0
worker01-kubeadm-k8s   Ready    <none>   3m6s    v1.14.0
worker02-kubeadm-k8s   Ready    <none>   2m41s   v1.14.0

安装初体验

01 `定义pod.yml文件，比如pod_nginx_rs.yaml` 【不能使用tab，只能用空格】
  mkdir pod_nginx_rs
  cd pod_nginx_rs
# =======================================================================================
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
# =======================================================================================
#02 根据pod_nginx_rs.yml文件创建pod,这里可能比较慢，要等会才会有结果
  kubectl apply -f pod_nginx_rs.yaml
#03 查看pod
    kubectl get pods
    kubectl get pods -o wide
    kubectl describe pod nginx
#04 感受通过rs将pod扩容
  kubectl scale rs nginx --replicas=5
  kubectl get pods -o wide
#05 删除pod
  kubectl delete -f pod_nginx_rs.yaml