kubeadm搭建K8S集群小记

概述

一时兴起，尝试下K8S集群的搭建

步骤

请查看参考链接1

Q&A

Q: raw.githubusercontent.com被墙，导致kube-flannel.yml下不来

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.ymlThe connection to the server raw.githubusercontent.com was refused - did you specify the right host or port?

A:
请查看参考链接2

Q: Worker节点加入集群报错

[root@192 ~]# kubeadm join 192.168.0.109:6443 --token 24alfb.pv5eec2dtb6vh94e \
>     --discovery-token-ca-cert-hash sha256:3c5d6820ee64d1d818bdab58a2f86a1316b09e5218258e96401ce73b3b4928b6 --node-name k8s-worker
[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 Hostname]: hostname "k8s-worker" could not be reached[WARNING Hostname]: hostname "k8s-worker": lookup k8s-worker on 192.168.1.1:53: no such host
error execution phase preflight: [preflight] Some fatal errors occurred:[ERROR Swap]: running with swap on is not supported. Please disable swap
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
To see the stack trace of this error execute with --v=5 or higher

A: Worker主机没有关闭交换内存导致的问题，执行“swapoff -a” 临时关闭内存后，重新执行成功

Q: Worker节点查看执行kubectl get pod报错

[root@192 ~]# kubectl get nodes
The connection to the server localhost:8080 was refused - did you specify the right host or port?

A: 将master节点中的/etc/kubernetes/admin.conf文件拷贝到Worker节点相同目录,然后执行以下命令

export KUBECONFIG=/etc/kubernetes/admin.conf#设置用户环境变量，避免每次都需要export
#echo "export KUBECONFIG=/etc/kubernetes/admin.conf" >> ~/.bash_profile

Q: 运行POD容器，报以下错误

[root@192 myservice]# kubectl run -it busybox --rm=true --image=busybox:1.28.4 -- /bin/sh
If you don't see a command prompt, try pressing enter.
Error attaching, falling back to logs: error dialing backend: dial tcp 192.168.0.112:10250: connect: no route to host
pod "busybox" deleted
Error from server: Get "https://192.168.0.112:10250/containerLogs/default/busybox/busybox": dial tcp 192.168.0.112:10250: connect: no route to host

A: 经过排查，是Worker主机没有关闭防火墙引起的问题