问题信息

1.kubectl命令查看信息报如下问题(系统版本为 Ubuntu-18-04)：

root@k8s-node2:~# kubectl get node
The connection to the server localhost:8080 was refused - did you specify the right host or port?

2.查看kubelet状态发现为未启动状态

root@k8s-node2:~# systemctl status kubelet
● kubelet.service - kubelet: The Kubernetes Node Agent
   Loaded: loaded (/lib/systemd/system/kubelet.service; enabled; vendor preset: enabled)
  Drop-In: /etc/systemd/system/kubelet.service.d
           └─10-kubeadm.conf
   Active: activating (auto-restart) (Result: exit-code) since Mon 2022-01-10 20:54:05 CST; 2s ago

3.重启kubelet后无效，仍为未启动状态
4.关闭swap后，重启成功。

root@k8s-node1:~# swapoff -a
root@k8s-node1:~# free
              total        used        free      shared  buff/cache   available
Mem:        2017444      279420      151024         860     1587000     1551172
Swap:             0           0           0
root@k8s-node1:~# systemctl start kubelet
root@k8s-node1:~# systemctl status kubelet
● kubelet.service - kubelet: The Kubernetes Node Agent
   Loaded: loaded (/lib/systemd/system/kubelet.service; enabled; vendor preset: enabled)
  Drop-In: /etc/systemd/system/kubelet.service.d
           └─10-kubeadm.conf
   Active: active (running) since Mon 2022-01-10 20:32:25 CST; 23s ago

总结

kubelet启动时需要关闭swap交换空间。
永久关闭swap方法为将/etc/fstab 文件中/swap开头的行注释掉即可。