6443: connect: network is unreachable

K8s API Server的鉴权问题由来已久。默认情况下K8s API Server会开启两个端口：8080(Localhost Port)和 6443(Secure Port)，其中8080端口为WEB UI Dashboard，无需认证，用于本地测试与监控；6443端口需要认证且有TLS保护，用于远程连接(如：通过kubectl管理集群)。

root@ubuntu:~# kubectl label node bogon  node-role.kubernetes.io/worker=worker
Unable to connect to the server: dial tcp 10.10.16.82:6443: connect: network is unreachable
root@ubuntu:~#   systemctl status  firewalld
Unit firewalld.service could not be found.
root@ubuntu:~# 

root@ubuntu:~# kubeadm reset

root@ubuntu:~# kubeadm init --kubernetes-version=v1.18.1  --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=10.10.16.82  --image-repository registry.aliyuncs.com/google_containers
W0618 18:47:56.560541    2512 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]
[init] Using Kubernetes version: v1.18.1
[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/
error execution phase preflight: [preflight] Some fatal errors occurred:
        [ERROR FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables does not exist
[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
root@ubuntu:~# echo 1 > /proc/sys/net/bridge/bridge-nf-call-iptables
-bash: /proc/sys/net/bridge/bridge-nf-call-iptables: No such file or directory

root@ubuntu:~# modprobe br_netfilter
root@ubuntu:~# echo 1 > /proc/sys/net/bridge/bridge-nf-call-iptables
-bash: /proc/sys/net/bridge/bridge-nf-call-iptables: No such file or directory
root@ubuntu:~# ls /proc/sys/net/bridge
ls: cannot access '/proc/sys/net/bridge': No such file or directory
root@ubuntu:~# 

MASTER端+NODE共同服务
systemctl restart etcd
systemctl daemon-reload
systemctl enable flanneld
systemctl restart flanneld

MASTER端独有服务
systemctl daemon-reload
systemctl enable kube-apiserver
systemctl restart kube-apiserver

systemctl daemon-reload
systemctl enable kube-controller-manager
systemctl restart kube-controller-manager

systemctl daemon-reload
systemctl enable kube-scheduler
systemctl restart kube-scheduler

NODE端独有服务
systemctl daemon-reload
systemctl enable kubelet
systemctl restart kubelet（status状态为 not ready时候重启即可）

systemctl daemon-reload
systemctl enable kube-proxy
systemctl restart kube-proxy

systemctl status etcd
systemctl status flanneld
systemctl status kube-apiserver
systemctl status kube-controller-manager
systemctl status kube-scheduler
systemctl status kubelet
systemctl status kube-proxy

标签：status,bridge,network,systemctl,6443,ubuntu,unreachable,kube,root
来源： https://www.cnblogs.com/dream397/p/14900907.html