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188 lines
5.3 KiB
Go
188 lines
5.3 KiB
Go
# 使用 kubeadm 部署 kubernetes
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`kubeadm` 提供了 `kubeadm init` 以及 `kubeadm join` 这两个命令作为快速创建 `kubernetes` 集群的最佳实践。
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## 安装 Docker
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参考 [安装 Docker](../../install) 一节安装 Docker。
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## 安装 **kubelet** **kubeadm** **kubectl**
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### Ubuntu/Debian
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```bash
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$ apt-get update && apt-get install -y apt-transport-https
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$ curl https://mirrors.aliyun.com/kubernetes/apt/doc/apt-key.gpg | apt-key add -
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$ cat <<EOF | sudo tee /etc/apt/sources.list.d/kubernetes.list
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deb https://mirrors.aliyun.com/kubernetes/apt/ kubernetes-xenial main
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EOF
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$ apt-get update
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$ apt-get install -y kubelet kubeadm kubectl
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```
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### CentOS/Fedora
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```bash
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$ cat <<EOF | sudo tee /etc/yum.repos.d/kubernetes.repo
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[kubernetes]
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name=Kubernetes
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baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
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enabled=1
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gpgcheck=1
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repo_gpgcheck=1
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gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
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EOF
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$ sudo yum install -y kubelet kubeadm kubectl
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```
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## 修改内核的运行参数
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```bash
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$ cat <<EOF | sudo tee /etc/sysctl.d/99-kubernetes-cri.conf
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net.bridge.bridge-nf-call-iptables = 1
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net.ipv4.ip_forward = 1
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net.bridge.bridge-nf-call-ip6tables = 1
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EOF
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# 应用配置
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$ sysctl --system
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```
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## 配置 kubelet
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### 修改 `kubelet.service`
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`/etc/systemd/system/kubelet.service.d/10-proxy-ipvs.conf` 写入以下内容
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```bash
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# 启用 ipvs 相关内核模块
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[Service]
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ExecStartPre=-/sbin/modprobe ip_vs
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ExecStartPre=-/sbin/modprobe ip_vs_rr
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ExecStartPre=-/sbin/modprobe ip_vs_wrr
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ExecStartPre=-/sbin/modprobe ip_vs_sh
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```
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执行以下命令应用配置。
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```bash
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$ sudo systemctl daemon-reload
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```
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## 部署
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### master
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```bash
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$ sudo kubeadm init --image-repository registry.cn-hangzhou.aliyuncs.com/google_containers \
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--pod-network-cidr 10.244.0.0/16 \
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--v 5 \
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--ignore-preflight-errors=all
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```
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* `--pod-network-cidr 10.244.0.0/16` 参数与后续 CNI 插件有关，这里以 `flannel` 为例，若后续部署其他类型的网络插件请更改此参数。
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> 执行可能出现错误，例如缺少依赖包，根据提示安装即可。
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执行成功会输出
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```bash
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...
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[addons] Applied essential addon: CoreDNS
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I1116 12:35:13.270407 86677 request.go:538] Throttling request took 181.409184ms, request: POST:https://192.168.199.100:6443/api/v1/namespaces/kube-system/serviceaccounts
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I1116 12:35:13.470292 86677 request.go:538] Throttling request took 186.088112ms, request: POST:https://192.168.199.100:6443/api/v1/namespaces/kube-system/configmaps
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[addons] Applied essential addon: kube-proxy
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Your Kubernetes control-plane has initialized successfully!
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To start using your cluster, you need to run the following as a regular user:
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mkdir -p $HOME/.kube
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sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
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sudo chown $(id -u):$(id -g) $HOME/.kube/config
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You should now deploy a pod network to the cluster.
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Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
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https://kubernetes.io/docs/concepts/cluster-administration/addons/
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Then you can join any number of worker nodes by running the following on each as root:
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kubeadm join 192.168.199.100:6443 --token cz81zt.orsy9gm9v649e5lf \
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--discovery-token-ca-cert-hash sha256:5edb316fd0d8ea2792cba15cdf1c899a366f147aa03cba52d4e5c5884ad836fe
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```
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### node 工作节点
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在 **另一主机** 重复 **部署** 小节以前的步骤，安装配置好 kubelet。根据提示，加入到集群。
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```bash
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$ kubeadm join 192.168.199.100:6443 --token cz81zt.orsy9gm9v649e5lf \
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--discovery-token-ca-cert-hash sha256:5edb316fd0d8ea2792cba15cdf1c899a366f147aa03cba52d4e5c5884ad836fe
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```
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## 查看服务
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所有服务启动后，查看本地实际运行的 Docker 容器。这些服务大概分为三类：主节点服务、工作节点服务和其它服务。
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### 主节点服务
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* `apiserver` 是整个系统的对外接口，提供 RESTful 方式供客户端和其它组件调用；
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* `scheduler` 负责对资源进行调度，分配某个 pod 到某个节点上；
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* `controller-manager` 负责管理控制器，包括 endpoint-controller（刷新服务和 pod 的关联信息）和 replication-controller（维护某个 pod 的复制为配置的数值）。
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### 工作节点服务
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* `proxy` 为 pod 上的服务提供访问的代理。
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### 其它服务
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* Etcd 是所有状态的存储数据库；
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## 使用
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将 `/etc/kubernetes/admin.conf` 复制到 `~/.kube/config`
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执行 `$ kubectl get all -A` 查看启动的服务。
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由于未部署 CNI 插件，CoreDNS 未正常启动。如何使用 Kubernetes，请参考后续章节。
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## 部署 CNI
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这里以 `flannel` 为例进行介绍。
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### flannel
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检查 podCIDR 设置
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```bash
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$ kubectl get node -o yaml | grep CIDR
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# 输出
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podCIDR: 10.244.0.0/16
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podCIDRs:
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```
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```bash
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$ kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/v0.11.0/Documentation/kube-flannel.yml
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```
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## master 节点默认不能运行 pod
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如果用 `kubeadm` 部署一个单节点集群，默认情况下无法使用，请执行以下命令解除限制
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```bash
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$ kubectl taint nodes --all node-role.kubernetes.io/master-
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# 恢复默认值
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# $ kubectl taint nodes NODE_NAME node-role.kubernetes.io/master=true:NoSchedule
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```
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## 参考文档
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* [官方文档](https://kubernetes.io/zh/docs/setup/independent/create-cluster-kubeadm/)
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