How To Add Worker Node Across Region in same K8S in OCI

Requirement:

   We would like to spread our kubernetes workload across region. So we can have safer DR solution for our services. ie we have  worker nodes in phoenix of OCI, we would like to add new worker nodes in ashburn of OCI within the same tenancy  and the same kubernetes cluster. This wiki is based on oracle provided kubernete and container service  see official doc .

Solution:

   The main part is on firewall side between the 2 regions. As long as the ports are open  among nodes for kubernetes own communication and services of pods. It would be fine. The network we use flannel which is on VXLAN.
   Once firewall ports are open, refer this blog to add a new worker node

Firewall Part :

Kubernetes own communctions between the 2 regions

All the worker nodes in the clusters should open "ports:  10250  8472"  to be able to receive connections

Source: All the nodes

Destination : worker nodes

port: TCP: 10250  UDP:8472

All  Master nodes should open "port : 6443" (API server)  to be able to receive  connections

Source: All worker nodes  and  End users Program to access API server

Destation : Master nodes

port: 6443 

All  Etcd nodes should open "port :  2379 " (etcd service) to be able to receive  connections

Source: All the nodes ,

Destation : Etcd nodes

port: 2379

All  services ports need to be exposed to outside kubernetes
Source: 0.0.0.0 or  restricted users depends on what services
Destation : All the worker nodes
port: the ports to be exposed