1.实验，一台master主机和两台work主机搭建k8s集群
三台机器都需要开启虚拟化，master主机的内存和cpu数多点 master至少2核数，node节点至少1核数 以下操作是三台机器都需要操作相同步骤 分别在三台服务器 ssh-keygen ssh-copy-id work1ssh-copy-id master
去/root/.ssh目录下有个authorized_keys文件就是免密登录
#临时关闭 swapoff -a
#永久关闭vim /etc/fstab 注释掉
/dev/mapper/centos-swap swap swap defaults 0 0
4.为什么要关闭swap交换分区？
Swap是交换分区，如果机器内存不够，会使用swap分区，但是swap分区的性能较低，k8s设计的时候为了能提升性能，默认是不允许使用交换分区的。Kubeadm初始化的时候会检测swap是否关闭，如果没关闭，那就初始化失败。如果不想要关闭交换分区，安装k8s的时候可以指定--ignore-preflight-errors=Swap来解决。 5.修改内核参数，添加网桥过滤器和IP路由转发，这样看s集群就可以通过路由进行转发[root@master sysctl.d]# cat /etc/sysctl.d/kubernetes.conf net.bridge.bridge-nf-call-ip6tables=1 net.bridge.bridge-nf-call-iptables=1 net.ipv4.ip_forward=16.重新加载配置
[root@master sysctl.d]# sysctl -p vm.max_map_count = 262144 net.ipv4.ip_forward = 1
7.加载网桥过滤模块
[root@master sysctl.d]# modprobe br_netfilter
8。查看网桥过滤器是否成功开启
[root@master sysctl.d]# lsmod |grep br_netfilter br_netfilter 22256 0 bridge 151336 1 br_netfilter
9.配置ipvs功能，安装ipset和ipvsadm
yum install -y ipvsadm ipset
[root@master yum.repos.d]# cat /etc/sysconfig/modules/ipvs.modules #!/bin/bash modprobe -- ip_vs modprobe -- ip_vs_sh modprobe -- ip_vs_rr modprobe -- ip_vs_wrr modprobe -- nf_conntrack_ipv4
对脚本添加执行权限
[root@master ]# chmod +x /etc/sysconfig/modules/ipvs.modules
启动脚本 /etc/sysconfig/modules/ipvs.modules
11.查看对应模块是否启动成功[root@master yum.repos.d]# lsmod | grep ip_vs
ip_vs_wrr 12697 0
ip_vs_rr 12600 0
ip_vs_sh 12688 0
ip_vs 145458 6 ip_vs_rr,ip_vs_sh,ip_vs_wrr
nf_conntrack 139264 7 ip_vs,nf_nat,nf_nat_ipv4,xt_conntrack,nf_nat_masquerade_ipv4,nf_conntrack_netlink,nf_conntrack_ipv4
libcrc32c 12644 4 xfs,ip_vs,nf_nat,nf_conntrack
12.kubernetes集群部署
三台机器都安装docker-ce kubelet kubeadm kubectl
（1）安装docker-ce源
要安装docker需要去阿里云搜docker-ce的源，再用yum 安装docker-ce就可以
kubelet kubeadm kubectl可以用Yum list kubelet搜索可安装的软件包
[root@master ~]# yum list kubelet 已加载插件：fastestmirror Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com 已安装的软件包 kubelet.x86_64 1.24.2-0 @kubernetes
（2）安装kubelet kubeadm kubectl 先不启动kubelet
yum install -y kubeadm kubelet kubectlKubeadm: kubeadm是一个工具，用来初始化k8s集群的 kubelet: 安装在集群所有节点上，用于启动Pod的 kubectl: 通过kubectl可以部署和管理应用，查看各种资源，创建、删除和更新各种组件
（3）查看docker版本
[root@master ~]# docker --version Docker version 20.10.15, build fd82621
(4)使用kubeadm初始化k8s集群
先查看下部署集群所需要的镜像，可以看到下面都是镜像
[root@work1 ~]# kubeadm config images list k8s.gcr.io/kube-apiserver:v1.24.3 k8s.gcr.io/kube-controller-manager:v1.24.3 k8s.gcr.io/kube-scheduler:v1.24.3 k8s.gcr.io/kube-proxy:v1.24.3 k8s.gcr.io/pause:3.7 k8s.gcr.io/etcd:3.5.3-0 k8s.gcr.io/coredns/coredns:v1.8.6
可以用二进制方法下载这几个容器，依次操作这几个镜像，注意：kubeadm默认从k8s.grc.io拉取镜像，但是k8s.gcr.io访问不到，所以需要指定从registry.aliyuncs.com/google_containers仓库拉取镜像。
[root@work1 ~]# docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.24.3 #从阿里云下载镜像 [root@work1 ~]# docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.24.3 k8s.gcr.io/kube-scheduler:v1.24.3 #给镜像打标签k8s.gcr.io/kube-scheduler:v1.24.3
[root@work1 ~]# docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.24.3 #删除不需要用的阿里云镜像文件
[root@master ~]# for imageName in ${images[@]};do
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName k8s.gcr.io/$imageName
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
done
(5)查看镜像是否下载好了
[root@work2 ~]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
k8s.gcr.io/kube-proxy v1.17.4 6dec7cfde1e5 2 years ago 116MB
k8s.gcr.io/kube-apiserver v1.17.4 2e1ba57fe95a 2 years ago 171MB
k8s.gcr.io/kube-controller-manager v1.17.4 7f997fcf3e94 2 years ago 161MB
k8s.gcr.io/kube-scheduler v1.17.4 5db16c1c7aff 2 years ago 94.4MB
k8s.gcr.io/coredns 1.6.5 70f311871ae1 2 years ago 41.6MB
k8s.gcr.io/etcd 3.4.3-0 303ce5db0e90 2 years ago 288MB
k8s.gcr.io/pause 3.1 da86e6ba6ca1 4 years ago 742kB
（6）kubernetes集群初始化
Master节点创建集群（该操作只在master主机执行）
可以用kubeadm --help查看帮助信息
[root@master ~]# kubeadm init --kubernetes-version=v1.24.3 --pod-network-cidr=10.244.0.0/16 --service-cidr=10.96.0.0/12 --apiserver-advertise-address=192.168.213.4 --image-repository registry.aliyuncs.com/google_containers
注释：--kubernetes-version=v1.17.4 \ # kubernetes版本
--pod-network-cidr=10.244.0.0/16 #k8s给pod节点分配的ip地址
--service-cidr=10.96.0.0/12 \ #给客户访问的备选地址
--apiserver-advertise-address=192.168.213.4 #master的ip
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 192.168.213.8:6443 --token 1bl657.59pad6tz14nvhp3j \ --discovery-token-ca-cert-hash sha256:61fb5e8ca294bea610601f26535cc0f5c991185c665b4d842adcffc909c5d417
根据提示操作
[root@master ~]# mkdir -p $HOME/.kube [root@master ~]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config [root@master ~]# sudo chown $(id -u):$(id -g) $HOME/.kube/config
可以去https://kubernetes.io/docs/concepts/cluster-administration/addons/网址下载.yaml文件，也可以wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml执行文件
[root@master ~]# kubectl apply -f /root/kube-flannel.yml namespace/kube-flannel 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
在node子节点执行
[root@work1 ~]# kubeadm join 192.168.213.3:6443 --token eafk7y.fe1nzff9ptjs3tuk \ > --discovery-token-ca-cert-hash sha256:363741efccddbabf7f93d50bd0914dfd8d059909306a8542b0e06a4172264d8f W0720 09:10:26.480050 2844 join.go:346] [preflight] WARNING: JoinControlPane.controlPlane settings will be ignored when control-plane flag is not set. [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-1.17" 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] 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.
查看下集群节点状态，可以看到是notready状态，执行下网络文件就可以
（7）安装kubernetes的网络插件 https://kubernetes.io/docs/concepts/cluster-administration/addons/kubernetes支持多种网络插件，如：flannel、calico、canal等（面试常问flannel跟calico的区别？）
只在master节点安装flannel插件即可，该插件使用的是DaemonSet控制器，该控制器会在每个节点上都运行
[root@master ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
master NotReady master 3m16s v1.17.4
work1 NotReady <none> 17s v1.17.4
work2 NotReady <none> 32s v1.17.4
work3 NotReady <none> 32s v1.17.4
root@master ~]# kubectl apply -f kube-flannel.yml namespace/kube-flannel unchanged clusterrole.rbac.authorization.k8s.io/flannel unchanged clusterrolebinding.rbac.authorization.k8s.io/flannel unchanged serviceaccount/flannel unchanged configmap/kube-flannel-cfg unchanged daemonset.apps/kube-flannel-ds unchanged
[root@master ~]# kubectl get nodes NAME STATUS ROLES AGE VERSION master Ready master 7m22s v1.17.4 work1 Ready worker 4m23s v1.17.4 work2 Ready worker 4m38s v1.17.4 work3 Ready worker 4m38s v1.17.4
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