内容简介:使用kubeadm搭建一个单节点kubernets实例,仅供学习. 运行环境和软件概要如下:以上系统和软件基本是2018最新的状态, 其中docker需要注意必须安装k8s支持到的版本.2.1 准备镜像
0. 概要
使用kubeadm搭建一个单节点kubernets实例,仅供学习. 运行环境和软件概要如下:
~ | 版本 | 备注 |
---|---|---|
OS | Ubuntu 18.0.4 | 192.168.132.152 my.servermaster.local/192.168.132.154 my.worker01.local |
Docker | 18.06.1~ce~3-0~ubuntu | k8s最新版(1.12.3)支持的最高版本, 必须固定 |
Kubernetes | 1.12.3 | 目标软件新 |
以上系统和软件基本是2018最新的状态, 其中 docker 需要注意必须安装k8s支持到的版本.
1. 安装步骤
- 关闭防火墙
swapoff -a
- 安装运行时, 默认使用docker, 安装docker即可
apt-get install docker-ce=18.06.1~ce~3-0~ubuntu
- 安装kubeadm 一下命令和官网的命令一致, 但是是包源改为阿里云
apt-get update && apt-get install -y apt-transport-https curl -s https://mirrors.aliyun.com/kubernetes/apt/doc/apt-key.gpg | apt-key add - cat <<EOF >/etc/apt/sources.list.d/kubernetes.list deb https://mirrors.aliyun.com/kubernetes/apt/ kubernetes-xenial main EOF apt-get update apt-get install -y kubelet kubeadm kubectl apt-mark hold kubelet kubeadm kubectl
2. 使用kubeadm创建集群
2.1 准备镜像
因为国内是访问不到k8s.gcr.io所以需要将需要的镜像提前下载, 这次采用从阿里云镜像仓库下载, 并修改下载后的镜像tag为k8s.gcr.io
# a. 查看都需要哪些镜像需要下载 kubeadm config images list --kubernetes-version=v1.12.3 k8s.gcr.io/kube-apiserver:v1.12.3 k8s.gcr.io/kube-controller-manager:v1.12.3 k8s.gcr.io/kube-scheduler:v1.12.3 k8s.gcr.io/kube-proxy:v1.12.3 k8s.gcr.io/pause:3.1 k8s.gcr.io/etcd:3.2.24 k8s.gcr.io/coredns:1.2 # b. 创建一个自动处理脚本下载镜像->重新tag->删除老tag vim ./load_images.sh #!/bin/bash ### config the image map declare -A images map=() images["k8s.gcr.io/kube-apiserver:v1.12.3"]="registry.cn-hangzhou.aliyuncs.com/google_containers/kube-apiserver:v1.12.3" images["k8s.gcr.io/kube-controller-manager:v1.12.3"]="registry.cn-hangzhou.aliyuncs.com/google_containers/kube-controller-manager:v1.12.3" images["k8s.gcr.io/kube-scheduler:v1.12.3"]="registry.cn-hangzhou.aliyuncs.com/google_containers/kube-scheduler:v1.12.3" images["k8s.gcr.io/kube-proxy:v1.12.3"]="registry.cn-hangzhou.aliyuncs.com/google_containers/kube-proxy:v1.12.3" images["k8s.gcr.io/pause:3.1"]="registry.cn-hangzhou.aliyuncs.com/google_containers/pause:3.1" images["k8s.gcr.io/etcd:3.2.24"]="registry.cn-hangzhou.aliyuncs.com/google_containers/etcd:3.2.24" images["k8s.gcr.io/coredns:1.2.2"]="registry.cn-hangzhou.aliyuncs.com/google_containers/coredns:1.2.2" ### re-tag foreach for key in ${!images[@]} do docker pull ${images[$key]} docker tag ${images[$key]} $key docker rmi ${images[$key]} done ### check docker images # c. 执行脚本准镜像 sudo chmod +x load_images.sh ./load_images.sh
2.2 初始化集群(master)
初始化需要指定至少两个参数:
- kubernetes-version: 方式kubeadm访问外网获取版本
- pod-network-cidr: flannel网络插件配置需要
### 执行初始化命令 sudo kubeadm init --kubernetes-version=v1.12.3 --pod-network-cidr=10.244.0.0/16 ### 最后的结果如下 ... ... Your Kubernetes master 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/ You can now join any number of machines by running the following on each node as root: kubeadm join 192.168.132.152:6443 --token ymny55.4jlbbkxiggmn9ezh --discovery-token-ca-cert-hash sha256:70265fafdb22d524c15616543d0b76527c686329221340b3b8da3652abed46b9
2.3 根据成功信息配置非管理员账号使用kubectl
mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config
使用非root账号查看节点情况:
kubectl get nodes NAME STATUS ROLES AGE VERSION servermaster NotReady master 28m v1.12.3
发现有一个master节点, 但是状态是NotReady, 这里需要做一个决定:
如果希望是单机则执行如下
kubectl taint nodes --all node-role.kubernetes.io/master-
如果希望搭建继续, 则继续后续步骤, 此时主节点状态可以忽略.
2.4 应用网络插件
查看 kube-flannel.yml 文件内容, 复制到本地文件避免terminal无法远程获取
kubectl apply -f kube-flannel.yml clusterrole.rbac.authorization.k8s.io/flannel created clusterrolebinding.rbac.authorization.k8s.io/flannel created serviceaccount/flannel created configmap/kube-flannel-cfg created daemonset.extensions/kube-flannel-ds-amd64 created daemonset.extensions/kube-flannel-ds-arm64 created daemonset.extensions/kube-flannel-ds-arm created daemonset.extensions/kube-flannel-ds-ppc64le created daemonset.extensions/kube-flannel-ds-s390x created
2.5 新建worker节点
worker节点新建参考[1. 安装步骤]在另外一台服务器上新建即可, worker节点不用准备2.1~2.3及之后的所有步骤, 仅需完成基本安装, 安装完毕进入新的worker节点, 执行上一步最后得到join命令:
kubeadm join 192.168.132.152:6443 --token ymny55.4jlbbkxiggmn9ezh --discovery-token-ca-cert-hash sha256:70265fafdb22d524c15616543d0b76527c686329221340b3b8da3652abed46b9 ... ... 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 master to see this node join the cluster.
2.6 检查集群(1 master, 1 worker)
kubectl get nodes NAME STATUS ROLES AGE VERSION servermaster Ready master 94m v1.12.3 worker01 Ready <none> 54m v1.12.3
2.5 创建dashboard
复制 kubernetes-dashboard.yaml 内容到本地文件
kubectl create -f kubernetes-dashboard.yaml secret/kubernetes-dashboard-certs created serviceaccount/kubernetes-dashboard created role.rbac.authorization.k8s.io/kubernetes-dashboard-minimal created rolebinding.rbac.authorization.k8s.io/kubernetes-dashboard-minimal created deployment.apps/kubernetes-dashboard created service/kubernetes-dashboard created
浏览器输入 worker节点 ip和端口使用 https 访问如下: https://my.worker01.local:30000/#!/login 即可以验证dashboard是否安装成功.
3. 遇到问题
-
master搭建好了, worker也join了get nodes发现还是NotReady状态
原因: 太复杂说不清楚任然是一个k8s issue , 查看issue基本可以确定是cni(Container Network Interface)问题,而flannel覆盖修改了这个问题
解决方法: 安装flannel插件(kubectl apply -f kube-flannel.yml )
-
配置错误重新开始搭建集群
解决方案: kubeadm reset
-
不能访问dashboard
原因: Back-off pulling image "k8s.gcr.io/kubernetes-dashboard-amd64:v1.10.0
解决方案:
-
修改 kubernetes-dashboard-ce.yaml 文件中的 k8s.gcr.io/kubernetes-dashboard-amd64:v1.10.0 为 registry.cn-hangzhou.aliyuncs.com/google_containers/kubernetes-dashboard-amd64:v1.10.0
-
提前下载好镜像并配置好tag, 注意下载的位置worker节点, 可以通过: kubectl describe pod kubernetes-dashboard-85477d54d7-wzt7 -n kube-system 查看比较具体的信息
-
4. 参考资料
安装kuadmin相关:
创建集群相关:
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