Hellxz博客资料

本文主要介绍Hellxz博客资料 方法和在新技术下所面对的“挑战”,方便大家深入理解Hellxz博客资料 过程。本文也将分享Hellxz博客资料 所遇到的问题和应对策略,怎么解决怎么做的问题。
通过深入本文可以理解代码原理,进行代码文档的下载,也可以查看相应 Demo 部署效果。

说明

本文系搭建kubernetes v1.18.5 集群笔记,使用三台虚拟机作为 CentOS 测试机,安装kubeadm、kubelet、kubectl均使用yum安装,网络组件选用的是 flannel

行文中难免出现错误,如果读者有高见,请评论与我交流

如需转载请注明原始出处 https://www.cnblogs.com/hellxz/p/use-kubeadm-init-kubernetes-cluster.html

环境准备

部署集群没有特殊说明均使用root用户执行命令

硬件信息

ip hostname mem disk explain
192.168.87.145 kube-master 4 GB 20GB k8s 控制平台节点
192.168.87.146 kube-node1 4 GB 20GB k8s 执行节点1
192.168.87.147 kube-node2 4 GB 20GB k8s 执行节点2

软件信息

software version
CentOS CentOS Linux release 7.7.1908 (Core)
Kubernetes v1.18.5
Docker 19.03.12

保证环境正确性

purpose commands
保证集群各节点互通 ping -c 3 <ip>
保证MAC地址唯一 ip linkifconfig -a
保证集群内主机名唯一 查询 hostnamectl status,修改 hostnamectl set-hostname <hostname>
保证系统产品uuid唯一 dmidecode -s system-uuidsudo cat /sys/class/dmi/id/product_uuid

修改MAC地址参考命令:

ifconfig eth0 down ifconfig eth0 hw ether 00:0C:18:EF:FF:ED ifconfig eth0 up 

如product_uuid不唯一,请考虑重装CentOS系统

确保端口开放正常

kube-master节点端口检查:

Protocol Direction Port Range Purpose
TCP Inbound 6443* kube-api-server
TCP Inbound 2379-2380 etcd API
TCP Inbound 10250 Kubelet API
TCP Inbound 10251 kube-scheduler
TCP Inbound 10252 kube-controller-manager

kube-node*节点端口检查:

Protocol Direction Port Range Purpose
TCP Inbound 10250 Kubelet API
TCP Inbound 30000-32767 NodePort Services

如果你对主机的防火墙配置不是很自信,可以关掉防火墙:

systemctl disable --now firewalld 

或者 清除iptables规则 (慎用)

iptables -F 

配置主机互信

分别在各节点配置hosts映射:

cat >> /etc/hosts <<EOF 192.168.87.145 kube-master 192.168.87.146 kube-node1 192.168.87.147 kube-node2 EOF 

kube-master生成ssh密钥,分发公钥到各节点:

#生成ssh密钥,直接一路回车 ssh-keygen -t rsa #复制刚刚生成的密钥到各节点可信列表中,需分别输入各主机密码 ssh-copy-id root@kube-master ssh-copy-id root@kube-node1 ssh-copy-id root@kube-node2 

禁用swap

swap仅当内存不够时会使用硬盘块充当额外内存,硬盘的io较内存差距极大,禁用swap以提高性能

各节点均需执行:

swapoff -a sed -i 's/.*swap.*/#&/' /etc/fstab 

关闭 SELinux

关闭 SELinux,否则 kubelet 挂载目录时可能报错 Permission denied,可以设置为permissivedisabledpermissive 会提示warn信息

各节点均需执行:

setenforce 0 sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/selinux/config 

设置系统时区、同步时间

timedatectl set-timezone Asia/Shanghai systemctl enable --now chronyd 

查看同步状态:

timedatectl status 

输出:

System clock synchronized: yes               NTP service: active           RTC in local TZ: no 
  • System clock synchronized: yes,表示时钟已同步;
  • NTP service: active,表示开启了时钟同步服务;
# 将当前的 UTC 时间写入硬件时钟 timedatectl set-local-rtc 0 # 重启依赖于系统时间的服务 systemctl restart rsyslog && systemctl restart crond 

部署docker

所有节点均需安装部署docker

添加docker yum源

#安装必要依赖 yum install -y yum-utils device-mapper-persistent-data lvm2 #添加aliyun docker-ce yum源 yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo #重建yum缓存 yum makecache fast 

安装docker

#查看可用docker版本 yum list docker-ce.x86_64 --showduplicates | sort -r 

Hellxz博客

#安装指定版本docker yum install -y docker-ce-19.03.12-3.el7 

这里以安装19.03.12版本举例,注意版本号不包含:与之前的数字

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确保网络模块开机自动加载

lsmod | grep overlay lsmod | grep br_netfilter 

若上面命令无返回值输出或提示文件不存在,需执行以下命令:

cat > /etc/modules-load.d/docker.conf <<EOF overlay br_netfilter EOF modprobe overlay modprobe br_netfilter 

使桥接流量对iptables可见

各节点均需执行:

cat > /etc/sysctl.d/k8s.conf <<EOF net.bridge.bridge-nf-call-ip6tables = 1 net.bridge.bridge-nf-call-iptables = 1 EOF sysctl --system 

验证是否生效,均返回 1 即正确

sysctl -n net.bridge.bridge-nf-call-iptables sysctl -n net.bridge.bridge-nf-call-ip6tables 

配置docker

mkdir /etc/docker #修改cgroup驱动为systemd[k8s官方推荐]、限制容器日志量、修改存储类型,最后的docker家目录可修改 cat > /etc/docker/daemon.json <<EOF {   "exec-opts": ["native.cgroupdriver=systemd"],   "log-driver": "json-file",   "log-opts": {     "max-size": "100m"   },   "storage-driver": "overlay2",   "storage-opts": [     "overlay2.override_kernel_check=true"   ],   "registry-mirrors": ["https://7uuu3esz.mirror.aliyuncs.com"],   "data-root": "/data/docker" } EOF #添加开机自启,立即启动 systemctl enable --now docker 

验证docker是否正常

#查看docker信息,判断是否与配置一致 docker info #hello-docker测试 docker run --rm hello-world #删除测试image docker rmi hello-world 

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添加用户到docker组

非root用户,无需sudo即可使用docker命令

#添加用户到docker组 usermod -aG docker <USERNAME> #当前会话立即更新docker组 newgrp docker 

部署kubernetes集群

未特殊说明,各节点均需执行如下步骤

添加kubernetes源

cat > /etc/yum.repos.d/kubernetes.repo <<EOF [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 #重建yum缓存,输入y添加证书认证 yum makecache fast 

安装kubeadm、kubelet、kubectl

各节点均需安装kubeadm、kubelet,kubectl仅kube-master节点需安装(作为worker节点,kubectl无法使用,可以不装)

yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes systemctl enable --now kubelet 

配置自动补全命令

#安装bash自动补全插件 yum install bash-completion -y #设置kubectl与kubeadm命令补全,下次login生效 kubectl completion bash >/etc/bash_completion.d/kubectl kubeadm completion bash > /etc/bash_completion.d/kubeadm 

预拉取kubernetes镜像

由于国内网络因素,kubernetes镜像需要从mirrors站点或通过dockerhub用户推送的镜像拉取

#查看指定k8s版本需要哪些镜像 kubeadm config images list --kubernetes-version v1.18.5 

Hellxz博客

另因阿里云的镜像暂时还没更新到v1.18.5版本,所以通过dockerhub上拉取,目前阿里云最新同步版本是v1.18.3,想通过v1.18.3版本拉取镜像请参考 <https://www.cnblogs.com/hellxz/p/13204093.html

/root/k8s 目录下,新建脚本get-k8s-images.sh,内容如下:

#!/bin/bash # Script For Quick Pull K8S Docker Images # by Hellxz Zhang <hellxz001@foxmail.com>  KUBE_VERSION=v1.18.5 PAUSE_VERSION=3.2 CORE_DNS_VERSION=1.6.7 ETCD_VERSION=3.4.3-0  # pull kubernetes images from hub.docker.com docker pull kubeimage/kube-proxy-amd64:$KUBE_VERSION docker pull kubeimage/kube-controller-manager-amd64:$KUBE_VERSION docker pull kubeimage/kube-apiserver-amd64:$KUBE_VERSION docker pull kubeimage/kube-scheduler-amd64:$KUBE_VERSION # pull aliyuncs mirror docker images docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/pause:$PAUSE_VERSION docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:$CORE_DNS_VERSION docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:$ETCD_VERSION  # retag to k8s.gcr.io prefix docker tag kubeimage/kube-proxy-amd64:$KUBE_VERSION  k8s.gcr.io/kube-proxy:$KUBE_VERSION docker tag kubeimage/kube-controller-manager-amd64:$KUBE_VERSION k8s.gcr.io/kube-controller-manager:$KUBE_VERSION docker tag kubeimage/kube-apiserver-amd64:$KUBE_VERSION k8s.gcr.io/kube-apiserver:$KUBE_VERSION docker tag kubeimage/kube-scheduler-amd64:$KUBE_VERSION k8s.gcr.io/kube-scheduler:$KUBE_VERSION docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/pause:$PAUSE_VERSION k8s.gcr.io/pause:$PAUSE_VERSION docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:$CORE_DNS_VERSION k8s.gcr.io/coredns:$CORE_DNS_VERSION docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:$ETCD_VERSION k8s.gcr.io/etcd:$ETCD_VERSION  # untag origin tag, the images won't be delete. docker rmi kubeimage/kube-proxy-amd64:$KUBE_VERSION docker rmi kubeimage/kube-controller-manager-amd64:$KUBE_VERSION docker rmi kubeimage/kube-apiserver-amd64:$KUBE_VERSION docker rmi kubeimage/kube-scheduler-amd64:$KUBE_VERSION docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/pause:$PAUSE_VERSION docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:$CORE_DNS_VERSION docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:$ETCD_VERSION 

脚本添加可执行权限,执行脚本拉取镜像:

chmod +x get-k8s-images.sh ./get-k8s-images.sh 

拉取完成,执行 docker images 查看镜像

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初始化kube-master

仅 kube-master 节点需要执行此步骤

修改kubelet配置默认cgroup driver

cat > /var/lib/kubelet/config.yaml <<EOF apiVersion: kubelet.config.k8s.io/v1beta1 kind: KubeletConfiguration cgroupDriver: systemd EOF systemctl restart kubelet 

生成kubeadm初始化配置文件 [可选] 仅当需自定义初始化配置时用

kubeadm config print init-defaults > init.default.yaml 

测试环境是否正常(WARNING是正常的)

kubeadm init phase preflight [--config kubeadm-init.yaml] 

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上图提示Warning是正常的,校验不了k8s信息是因为连不上被ban的网站,最后一个提示是因我本地未关闭防火墙,请我看清楚必要放行的端口号是否畅通

初始化master 10.244.0.0/16是flannel固定使用的IP段,设置取决于网络组件要求

kubeadm init --pod-network-cidr=10.244.0.0/16 --kubernetes-version=v1.18.5 [--config kubeadm-init.yaml] 

输出如下:

[root@kube-master k8s]# kubeadm init --pod-network-cidr=10.244.0.0/16 --kubernetes-version=v1.18.5 W0703 18:49:19.076654   16469 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io] [init] Using Kubernetes version: v1.18.5 [preflight] Running pre-flight checks 	[WARNING Firewalld]: firewalld is active, please ensure ports [6443 10250] are open or your cluster may not function correctly [preflight] Pulling images required for setting up a Kubernetes cluster [preflight] This might take a minute or two, depending on the speed of your internet connection [preflight] You can also perform this action in beforehand using 'kubeadm config images pull' [kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env" [kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml" [kubelet-start] Starting the kubelet [certs] Using certificateDir folder "/etc/kubernetes/pki" [certs] Generating "ca" certificate and key [certs] Generating "apiserver" certificate and key [certs] apiserver serving cert is signed for DNS names [kube-master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.87.145] [certs] Generating "apiserver-kubelet-client" certificate and key [certs] Generating "front-proxy-ca" certificate and key [certs] Generating "front-proxy-client" certificate and key [certs] Generating "etcd/ca" certificate and key [certs] Generating "etcd/server" certificate and key [certs] etcd/server serving cert is signed for DNS names [kube-master localhost] and IPs [192.168.87.145 127.0.0.1 ::1] [certs] Generating "etcd/peer" certificate and key [certs] etcd/peer serving cert is signed for DNS names [kube-master localhost] and IPs [192.168.87.145 127.0.0.1 ::1] [certs] Generating "etcd/healthcheck-client" certificate and key [certs] Generating "apiserver-etcd-client" certificate and key [certs] Generating "sa" key and public key [kubeconfig] Using kubeconfig folder "/etc/kubernetes" [kubeconfig] Writing "admin.conf" kubeconfig file [kubeconfig] Writing "kubelet.conf" kubeconfig file [kubeconfig] Writing "controller-manager.conf" kubeconfig file [kubeconfig] Writing "scheduler.conf" kubeconfig file [control-plane] Using manifest folder "/etc/kubernetes/manifests" [control-plane] Creating static Pod manifest for "kube-apiserver" [control-plane] Creating static Pod manifest for "kube-controller-manager" W0703 18:49:23.039913   16469 manifests.go:225] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC" [control-plane] Creating static Pod manifest for "kube-scheduler" W0703 18:49:23.040907   16469 manifests.go:225] the default kube-apiserver authorization-mode is "Node,RBAC"; using "Node,RBAC" [etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests" [wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s [apiclient] All control plane components are healthy after 21.505101 seconds [upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace [kubelet] Creating a ConfigMap "kubelet-config-1.18" in namespace kube-system with the configuration for the kubelets in the cluster [upload-certs] Skipping phase. Please see --upload-certs [mark-control-plane] Marking the node kube-master as control-plane by adding the label "node-role.kubernetes.io/master=''" [mark-control-plane] Marking the node kube-master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule] [bootstrap-token] Using token: 2b7cfv.6bhz4z3a3vzyg498 [bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles [bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to get nodes [bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials [bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token [bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster [bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace [kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key [addons] Applied essential addon: CoreDNS [addons] Applied essential addon: kube-proxy  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 192.168.87.145:6443 --token 2b7cfv.6bhz4z3a3vzyg498      --discovery-token-ca-cert-hash sha256:79bd63d82634f9953cc9d6b5a923fa87c973f0c3fd9ed7270167052dd834c026 

为日常使用集群的用户添加kubectl使用权限

su hellxz mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config exit 

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配置master认证

echo 'export KUBECONFIG=/etc/kubernetes/admin.conf' >> /etc/profile . /etc/profile 

如果不配置这个,会提示如下输出:

The connection to the server localhost:8080 was refused - did you specify the right host or port? 

此时master节点已经初始化成功,但是还未完装网络组件,还无法与其他节点通讯

安装网络组件,以flannel为例

cd ~/k8s yum install -y wget #下载flannel最新配置文件 wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml kubectl apply -f kube-flannel.yml 

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查看kube-master节点状态

kubectl get nodes 

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如果STATUS提示NotReady,可以通过 kubectl describe node kube-master 查看具体的描述信息,性能差的服务器到达Ready状态时间会长些

备份镜像供其他节点使用

在kube-master节点将镜像备份出来,便于后续传输给其他node节点,当然有镜像仓库更好

docker save k8s.gcr.io/kube-proxy:v1.18.5              k8s.gcr.io/kube-apiserver:v1.18.5              k8s.gcr.io/kube-controller-manager:v1.18.5              k8s.gcr.io/kube-scheduler:v1.18.5              k8s.gcr.io/pause:3.2              k8s.gcr.io/coredns:1.6.7              k8s.gcr.io/etcd:3.4.3-0 > k8s-imagesV1.18.5.tar 

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初始化kube-node*节点并加入集群

拷贝镜像到node节点,以kube-node1举例,node2不再累述

#此时命令在kube-node*节点上执行 mkdir ~/k8s scp root@kube-master:/root/k8s/k8s-imagesV1.18.5.tar ~/k8s 

获取加入kubernetes命令,未忘可不选

刚才在初始化kube-master节点时,有在最后输出其加入集群的命令,假如我没记下来,那怎么办呢?

访问kube-master输入创建新token命令,同时输出加入集群的命令:

kubeadm token create --print-join-command 

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在kube-node*节点上执行加入集群命令

kubeadm join 192.168.87.145:6443 --token jdyzyq.icwlpkm36kgs6nqh     --discovery-token-ca-cert-hash sha256:24f9b05fa10307ef6fff4132e0ec3c8b54917d4ff440b36108908aca588d8be7  

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查看集群节点状态

kubectl get nodes 

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参考

  • 《Kubernetes权威指南》第4版
  • 官方文档 https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/

至此,本文结束,感谢阅读,如果对你有帮助,欢迎点推荐,如果有问题,请在下方留言。

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