修改K8S Master节点IP后使用kubeadm join无法添加节点

修改K8S Master节点IP后使用kubeadm join无法添加节点

背景： 目前接了一个需求：修改使用kubeadm部署好的K8S环境所在服务器IP。很明显，修改服务器IP后，kube-apiserver等服务是无法启动的。在使用脚本重新生成了apiserver证书等一系列操作后，将所有的服务恢复后，测试使用kubeadm join添加新的节点一直失败，看日志是kubeadm期间会使用到服务器的旧IP，调试了很久，终于发现使用旧IP的地方，以下是排查过程，记录以下，共后续参考。

一、kubeadm join报错

旧IP： 192.168.12.110
新IP： 192.168.12.224

root@intellif-3:~# kubeadm join 192.168.12.224:6443 --token dperzp.19444xvuwd5lhr2n     --discovery-token-ca-cert-hash sha256:1db95da7507bd5b509eddc7aec24d4921334a175ab5b6b2e5bde66ccc128388a --cri-socket=/run/containerd/containerd.sock
[preflight] Running pre-flight checks
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'

error execution phase preflight: unable to fetch the kubeadm-config ConfigMap: failed to get config map: Get https://192.168.12.110:6443/api/v1/namespaces/kube-system/configmaps/kubeadm-config: dial tcp 192.168.12.110:6443: i/o timeout

二、打开kubeadm调试信息

• 在需要加入k8s集群的新服务器上执行如下命令：

kubeadm join 192.168.12.224:6443
 --token dperzp.19444xvuwd5lhr2n \
 --discovery-token-ca-cert-hash sha256:1db95da7507bd5b509eddc7aec24d4921334a175ab5b6b2e5bde66ccc128388a  \ 
 --cri-socket=/run/containerd/containerd.sock \
 -v=10

• 输出日志如下：

I0711 15:03:41.339810   32744 join.go:367] [preflight] found NodeName empty; using OS hostname as NodeName
[preflight] Running pre-flight checks
I0711 15:03:41.339943   32744 preflight.go:90] [preflight] Running general checks
I0711 15:03:41.339987   32744 checks.go:254] validating the existence and emptiness of directory /etc/kubernetes/manifests
I0711 15:03:41.340005   32744 checks.go:292] validating the existence of file /etc/kubernetes/kubelet.conf
I0711 15:03:41.340013   32744 checks.go:292] validating the existence of file /etc/kubernetes/bootstrap-kubelet.conf
I0711 15:03:41.340021   32744 checks.go:105] validating the container runtime
I0711 15:03:41.357074   32744 checks.go:382] validating the presence of executable crictl
I0711 15:03:41.357218   32744 checks.go:341] validating the contents of file /proc/sys/net/bridge/bridge-nf-call-iptables
I0711 15:03:41.357295   32744 checks.go:341] validating the contents of file /proc/sys/net/ipv4/ip_forward
I0711 15:03:41.357340   32744 checks.go:653] validating whether swap is enabled or not
I0711 15:03:41.357385   32744 checks.go:382] validating the presence of executable ip
I0711 15:03:41.357423   32744 checks.go:382] validating the presence of executable iptables
I0711 15:03:41.357454   32744 checks.go:382] validating the presence of executable mount
I0711 15:03:41.357485   32744 checks.go:382] validating the presence of executable nsenter
I0711 15:03:41.357512   32744 checks.go:382] validating the presence of executable ebtables
I0711 15:03:41.357542   32744 checks.go:382] validating the presence of executable ethtool
I0711 15:03:41.357571   32744 checks.go:382] validating the presence of executable socat
I0711 15:03:41.357