Actions to Take When Server IP Address Changes

You can make necessary configuration changes for Kubernetes Master and MongoDB when server IP address changes, renew certificates, and ensure services work properly.

Actions for Kubernetes Master:

#IPs are changed in the following files
/etc/kubernetes/admin.conf
/etc/kubernetes/controller-manager.conf
/etc/kubernetes/kubelet.conf
/etc/kubernetes/scheduler.conf
/etc/kubernetes/manifests/etcd.yaml
/etc/kubernetes/manifests/kube-apiserver.yaml

#Existing certificates are deleted
cd /etc/kubernetes/pki
rm -rf apiserver.* apiserver-kubelet-client.*

#New certificates are created (this stage may give errors but they can be ignored)
sudo kubeadm init phase certs apiserver-kubelet-client
sudo kubeadm init phase certs apiserver
sudo systemctl restart kubelet

#Current config file is moved under user for current user's access
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Actions for MongoDB:

#Connect to MongoDB
mongosh mongodb://<YOUR_NEW_MONGO_IP_ADDRESS>:25080 --authenticationDatabase "admin" -u "apinizer" -p

#New ip settings are given with "force" option
cfg = rs.conf()
cfg.members[0].host = "<YOUR_NEW_MONGO_IP_ADDRESS>:25080"
rs.reconfig(cfg, {force:true})