kubernetes环境的搭建步骤

这篇文章主要介绍"kubernetes环境的搭建步骤"，在日常操作中，相信很多人在kubernetes环境的搭建步骤问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答"kubernetes环境的搭建步骤"的疑惑有所帮助！接下来，请跟着小编一起来学习吧！

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

软件信息

保证环境正确性

# 修改MAC地址参考命令如下：# 1、关闭网卡ifconfig eth0 down# 2、修改macifconfig eth0 hw ether 00:E0:18:EE:ED# 3、开启网卡ifconfig eth0 up

⚠如果 product_uuid 不唯一，请考虑重装 CentOS 系统！！

确保端口开放正常

k8s-master 节点端口检查：

k8s-node* 节点端口检查：

如果你对主机的防火墙配置不是很自信，则可以关掉防火墙：

systemctl disable --now firewalld 或者清除 iptables 规则（iptables -F）【慎用】

配置主机互信

分别在各节点配置 hosts 映射：

cat >> /etc/hosts <
K8s-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@k8s-masterssh-copy-id root@k8s-node1ssh-copy-id root@k8s-node2ssh-copy-id root@k8s-node3
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以提供性能，各节点均需执行：
swapoff -ased -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permissive或disabled，permissive会提示warn信息 ，各节点均需执行：
setenforce 0sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/selinux/config
设置系统时区、同步时间
timedatectl set-timezone Asia/Shanghaisystemctl enable --now chronyd# 查看同步状态, 输出[root@ecs-2aae ~]# timedatectl status               Local time: Sun 2020-12-27 21:59:02 CST           Universal time: Sun 2020-12-27 13:59:02 UTC                 RTC time: Sun 2020-12-27 13:58:31                Time zone: Asia/Shanghai (CST, +0800)System clock synchronized: yes              NTP service: active          RTC in local TZ: no[root@ecs-2aae ~]# ## # systemctl clok synchronronize: 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器systemctl restart rsyslog && systemctl restart crond
部署Docker
所有节点均需安装部署 docker， 可参见《CentOS8 安装docker》
部署Kubernetes集群
无特殊说明，各节点均需执行如下步骤
添加kubernetes 源
cat < /etc/yum.repos.d/kubernetes.repo[kubernetes]name=Kubernetesbaseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64enabled=1gpgcheck=0repo_gpgcheck=0EOF
安装kubeadm、kubelet、kubectl
各节点均需安装 kubeadm、kubelet，kubectl仅 k8s-master 节点续约安装（作为 worker 节点， kubectl 无法使用， 可以不装）
yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetessystemctl 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/kubectlkubeadm completion bash > /etc/bash_completion.d/kubeadm
预拉取kubernetes镜像 （第一种方式）
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[root@ecs-2aae ~]# kubeadm config images listk8s.gcr.io/kube-apiserver:v1.20.1k8s.gcr.io/kube-controller-manager:v1.20.1k8s.gcr.io/kube-scheduler:v1.20.1k8s.gcr.io/kube-proxy:v1.20.1k8s.gcr.io/pause:3.2k8s.gcr.io/etcd:3.4.13-0k8s.gcr.io/coredns:1.7.0[root@ecs-2aae ~]#
在 /opt/soft/kuberetes 目录下，新建脚本pull-k8s-images.sh，内容如下：
#!/bin/bash# Script For Quick Pull K8S Docker Images# by WUXH  KUBE_VERSION=v1.20.1PAUSE_VERSION=3.2CORE_DNS_VERSION=1.7.0ETCD_VERSION=3.4.13-0# pull kubernetes images from hub.docker.comdocker pull kubeimage/kube-proxy:$KUBE_VERSIONdocker pull kubeimage/kube-controller-manager:$KUBE_VERSIONdocker pull kubeimage/kube-apiserver:$KUBE_VERSIONdocker pull kubeimage/kube-scheduler:$KUBE_VERSION# pull aliyuncs mirror docker imagesdocker pull registry.cn-hangzhou.aliyuncs.com/google_containers/pause:$PAUSE_VERSIONdocker pull registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:$CORE_DNS_VERSIONdocker pull registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:$ETCD_VERSION# retag to k8s.gcr.io prefixdocker tag kubeimage/kube-proxy:$KUBE_VERSION  k8s.gcr.io/kube-proxy:$KUBE_VERSIONdocker tag kubeimage/kube-controller-manager:$KUBE_VERSION k8s.gcr.io/kube-controller-manager:$KUBE_VERSIONdocker tag kubeimage/kube-apiserver:$KUBE_VERSION k8s.gcr.io/kube-apiserver:$KUBE_VERSIONdocker tag kubeimage/kube-scheduler:$KUBE_VERSION k8s.gcr.io/kube-scheduler:$KUBE_VERSIONdocker tag registry.cn-hangzhou.aliyuncs.com/google_containers/pause:$PAUSE_VERSION k8s.gcr.io/pause:$PAUSE_VERSIONdocker tag registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:$CORE_DNS_VERSION k8s.gcr.io/coredns:$CORE_DNS_VERSIONdocker tag registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:$ETCD_VERSION k8s.gcr.io/etcd:$ETCD_VERSION# untag origin tag, the images won't be delete.docker rmi kubeimage/kube-proxy:$KUBE_VERSIONdocker rmi kubeimage/kube-controller-manager:$KUBE_VERSIONdocker rmi kubeimage/kube-apiserver:$KUBE_VERSIONdocker rmi kubeimage/kube-scheduler:$KUBE_VERSIONdocker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/pause:$PAUSE_VERSIONdocker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:$CORE_DNS_VERSIONdocker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:$ETCD_VERSION
脚本添加可执行权限，执行脚本拉取镜像：
chmod +x pull-k8s-images.sh./opt/soft/kuberetes/pull-k8s-images.sh
拉取完成，执行 docker images 查看镜像：
kubernetes初始化指定镜像 （第二种方式）
kubeadm init --image-repository=registry.aliyuncs.com/google_containers --kubernetes-version=v1.20.1 --pod-network-cidr 10.244.0.0/16
输出如下：
[root@ecs-2aae ~]# kubeadm init --image-repository=registry.aliyuncs.com/google_containers --pod-network-cidr=10.244.0.0/16 --kubernetes-version=v1.20.1[init] Using Kubernetes version: v1.20.1[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/        [WARNING FileExisting-tc]: tc not found in system path        [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 20.10.1. Latest validated version: 19.03[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'[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 [ecs-2aae kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.1.61][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 [ecs-2aae localhost] and IPs [192.168.1.61 127.0.0.1 ::1][certs] Generating "etcd/peer" certificate and key[certs] etcd/peer serving cert is signed for DNS names [ecs-2aae localhost] and IPs [192.168.1.61 127.0.0.1 ::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[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[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"[control-plane] Creating static Pod manifest for "kube-scheduler"[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 7.501971 seconds[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace[kubelet] Creating a ConfigMap "kubelet-config-1.20" 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 ecs-2aae as control-plane by adding the labels "node-role.kubernetes.io/master=''" and "node-role.kubernetes.io/control-plane='' (deprecated)"[mark-control-plane] Marking the node ecs-2aae as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule][bootstrap-token] Using token: xksx1a.t09ok8h7w6ixnyva[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-proxyYour 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/configAlternatively, if you are the root user, you can run:  export KUBECONFIG=/etc/kubernetes/admin.confYou 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 192.168.1.61:6443 --token 379rcy.4k2gsoggyjxzo4u9 \    --discovery-token-ca-cert-hash sha256:a8f563cd1c742fa64eef6db0420401ecb57556281199989449f872da9f50609f[root@ecs-2aae ~]#
可能故障
故障1：k8s node节点加入集群报错[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver.# 解决cat < /etc/docker/daemon.json {   "exec-opts": ["native.cgroupdriver=systemd"]}EOF #重启dockersystemctl restart docker
为日常使用集群的用户添加kubectl使用权限，配置master认证
[root@ecs-2aae ~]# mkdir -p ~/.kube[root@ecs-2aae ~]# cp -i /etc/kubernetes/admin.conf ~/.kube/admin.conf[root@ecs-2aae ~]# chown $(id -u):$(id -g) ~/.kube/admin.conf[root@ecs-2aae ~]# echo 'export KUBECONFIG=/etc/kubernetes/admin.conf' >> /etc/profile[root@ecs-2aae ~]# . /etc/profile
安装网络组件，以flannel为例
[root@k8s-master ~]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.ymlpodsecuritypolicy.policy/psp.flannel.unprivileged createdclusterrole.rbac.authorization.k8s.io/flannel createdclusterrolebinding.rbac.authorization.k8s.io/flannel createdserviceaccount/flannel createdconfigmap/kube-flannel-cfg createddaemonset.apps/kube-flannel-ds created[root@k8s-master ~]#
Node节点加入集群
这句话其实就是Master节点执行kubeadm init成功之后输出的最后一句话，我们拿到Node节点中直接执行即可
kubeadm join 192.168.1.61:6443 --token 379rcy.4k2gsoggyjxzo4u9 \    --discovery-token-ca-cert-hash sha256:a8f563cd1c742fa64eef6db0420401ecb57556281199989449f872da9f50609f
输出：
[root@k8s-node1 ~]# kubeadm join 192.168.1.61:6443 --token 379rcy.4k2gsoggyjxzo4u9     --discovery-token-ca-cert-hash sha256:a8f563cd1c742fa64eef6db0420401ecb57556281199989449f872da9f50609f [preflight] Running pre-flight checks        [WARNING FileExisting-tc]: tc not found in system path        [WARNING SystemVerification]: this Docker version is not on the list of validated versions: 20.10.1. Latest validated version: 19.03[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: ### 节点加入成功啦* 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.[root@k8s-node1 ~]#
查看集群节点状态
[root@k8s-master ~]# kubectl get nodesNAME         STATUS   ROLES                  AGE   VERSIONk8s-master   Ready    control-plane,master   67m   v1.20.1k8s-node1    Ready                     40m   v1.20.1k8s-node2    Ready                     32m   v1.20.1k8s-node3    Ready                     30m   v1.20.1[root@k8s-master ~]#
⚠： 如果节点是 NoReady 状态，可以稍微等一会儿，集群节点会自动拉起 flannel 镜像，由于网络可能稍慢！！
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