部署单节点k8s并允许master节点调度pod
安装k8s
需要注意的是k8s1.24+ 已经弃用dockershim，现在使用docker需要cri-docker插件作为垫片，对接k8s的CRI。
硬件环境： 2c2g
主机环境： CentOS Linux release 7.9.2009 (Core)
IP地址： 192.168.44.161
一、 主机配置
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设置主机名
hostnamectl set-hostname k8s-master -
关闭selinux，防火墙
systemctl disable firewalld --now setenforce 0 sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config -
关闭swap分区
swapoff -a注释掉/etc/fstab的信息
二、 安装容器运行时
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安装docker engine
1.1. 安装和配置先决条件
转发 IPv4 并让 iptables 看到桥接流量
执行下述指令cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf overlay br_netfilter EOF sudo modprobe overlay sudo modprobe br_netfilter # 设置所需的 sysctl 参数，参数在重新启动后保持不变 cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf net.bridge.bridge-nf-call-iptables = 1 net.bridge.bridge-nf-call-ip6tables = 1 net.ipv4.ip_forward = 1 EOF # 应用 sysctl 参数而不重新启动 sudo sysctl --system # 通过运行以下指令确认 br_netfilter 和 overlay 模块被加载： lsmod | grep br_netfilter lsmod | grep overlay # 通过运行以下指令确认 net.bridge.bridge-nf-call-iptables、net.bridge.bridge-nf-call-ip6tables 和 net.ipv4.ip_forward 系统变量在你的 sysctl 配置中被设置为 1： sysctl net.bridge.bridge-nf-call-iptables net.bridge.bridge-nf-call-ip6tables net.ipv4.ip_forward1.2. 安装docker engine
curl -fsSL https://get.docker.com -o get-docker.sh sh get-docker.sh1.3. 启动自启
systemctl enable docker --now1.4. 修改cgroup
由于kubelet 和 容器运行时必须使用一致的cgroup驱动，kubelet 使用的是systemd 所以需要将docke
engine的cgroup修改为 systemcat > /etc/docker/daemon.json << EOF { "exec-opts": ["native.cgroupdriver=systemd"] } EOFsystemctl daemon-reload systemctl restart docker
三、 安装 docker engine 对接 cri 的垫片 cri-docker
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安装cri-docker
wget https://github.com/Mirantis/cri-dockerd/releases/download/v0.3.11/cri-dockerd-0.3.11-3.el7.x86_64.rpm rpm -ivh cri-dockerd-0.3.11-3.el7.x86_64.rpmsystemctl enable cri-docker --nowcri-docker 默认的socket文件在 /run/cri-dockerd.sock 后面会用到
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配置cri-docker
只需要配置 ExecStart=/usr/bin/cri-dockerd --container-runtime-endpoint
fd:// --network-plugin=cni
–pod-infra-container-image=registry.aliyuncs.com/google_containers/pause:3.9即可
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–network-plugin：指定网络插件规范的类型，这里要使用CNI
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–pod-infra-container-image：Pod中的puase容器要使用的Image,默认为registry.k8s.io上的pause仓库中的镜像,由于安装k8s使用阿里云的镜像仓库，所以提前指定 puase 镜像
vi /usr/lib/systemd/system/cri-docker.service[Unit] Description=CRI Interface for Docker Application Container Engine Documentation=https://docs.mirantis.com After=network-online.target firewalld.service docker.service Wants=network-online.target Requires=cri-docker.socket[Service] Type=notify ExecStart=/usr/bin/cri-dockerd --container-runtime-endpoint fd:// --network-plugin=cni --pod-infra-container-image=registry.aliyuncs.com/google_containers/pause:3.9 ExecReload=/bin/kill -s HUP $MAINPID TimeoutSec=0 RestartSec=2 Restart=always# Note that StartLimit* options were moved from "Service" to "Unit" in systemd 229. # Both the old, and new location are accepted by systemd 229 and up, so using the old location # to make them work for either version of systemd. StartLimitBurst=3# Note that StartLimitInterval was renamed to StartLimitIntervalSec in systemd 230. # Both the old, and new name are accepted by systemd 230 and up, so using the old name to make # this option work for either version of systemd. StartLimitInterval=60s# Having non-zero Limit*s causes performance problems due to accounting overhead # in the kernel. We recommend using cgroups to do container-local accounting. LimitNOFILE=infinity LimitNPROC=infinity LimitCORE=infinity# Comment TasksMax if your systemd version does not support it. # Only systemd 226 and above support this option. TasksMax=infinity Delegate=yes KillMode=process
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重新加载cri-docker
systemctl daemon-reload systemctl restart cri-docker
四、 部署k8s集群
1. 配置yum仓库（使用阿里云的镜像仓库）
cat > /etc/yum.repos.d/kubernetes.repo << EOF
[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.gpghttp://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
yum -y install kubeadm kubectl kubelet --disableexcludes=Kubernetes
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启动 kubelet
systemctl enable kubelet --now -
使用 kubeadm 创建集群
3.1. 修改初始集群默认配置文件kubeadm config print init-defaults > init-defaults.yamlvim init-defaults.yaml
apiVersion: kubeadm.k8s.io/v1beta3
bootstrapTokens:
- groups:- system:bootstrappers:kubeadm:default-node-tokentoken: abcdef.0123456789abcdefttl: 24h0m0susages:- signing- authentication
kind: InitConfiguration
localAPIEndpoint:advertiseAddress: 192.168.44.161 bindPort: 6443
nodeRegistration:criSocket: unix:///run/cri-dockerd.sockimagePullPolicy: IfNotPresentname: nodetaints: null
---
apiServer:timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta3
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns: {}
etcd:local:dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
kubernetesVersion: 1.28.0
networking:dnsDomain: cluster.localserviceSubnet: 10.96.0.0/12podSubnet: 10.244.0.0/16
scheduler: {}-
advertiseAddress 集群宣告地址（master地址）
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criSocket cri-docker 的socket文件的地址
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imageRepository 拉取镜像的地址（这里使用的是阿里云）
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podSubnet 设置pod的网络范围，后面安装网络插件必须和这个地址一致
3.2. 使用初始化配置文件，下载镜像
kubeadm config images list --config=init-defaults.yaml # 查看需要哪些镜像
kubeadm config images pull --config=init-defaults.yaml # 拉取镜像
3.3. 初始化集群
kubeadm init --config=init-defaults.yaml
3.4. 如果以root用户执行kub-ctl需要执行如下（根据提示执行）
export KUBECONFIG=/etc/kubernetes/admin.conf
3.5. 安装网络插件（这里使用简单的三层网络flannel）
kubectl apply -f https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml
五、 允许master节点调度pod
这是因为master配置了污点所有pod无法调度，只需要把污点删除即可（本地环境或者测试环境可以使用，生产不建议）
关于污点的官方文档介绍：
https://kubernetes.io/zh-cn/docs/concepts/scheduling-eviction/taint-and-toleration/
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查看节点的污点
kubectl describe nodes node | grep Taint
可以看出master节点被配置了 NoSchedule污点 -
删除污点
kubectl taint nodes node node-role.kubernetes.io/control-plane:NoSchedule-
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创建pod测试
kubectl run nginx --image=nginx
可以看出master节点现在也能调度pod了