<p>How to configure VPN connection between 2 Kubernetes clusters.</p>

<p>The case is:
- 2 kubernetes clusters running on different sites
- OpenVPN connectivity between 2 clusters 
- In both kubernetes clusters are installed openvpn running in separate container.</p>

<p>How to configure kubernetes clusters (vpn, routing, firewall configurations) so, the Nodes and Containers of any of the kubernetes clusters to have connectivity through VPN to nodes and services to the other cluster?</p>

<p>Thank you for the answers !!!</p>

<p>What you need in Kubernetes is called <a href="https://kubernetes.io/docs/concepts/cluster-administration/federation/" rel="nofollow noreferrer">federation</a>.</p>
<blockquote>
<h3>Deprecated</h3>
<p>Use of  <code>Federation v1</code>  is <strong>strongly discouraged</strong>.  <code>Federation V1</code>  never achieved GA status and is no longer under active development. Documentation is for historical purposes only.</p>
<p>For more information, see the intended replacement,  <a href="https://github.com/kubernetes-sigs/federation-v2" rel="nofollow noreferrer">Kubernetes Federation v2</a>.</p>
</blockquote>
<p>As for using a VPN in Kubernetes, I recommend <a href="https://medium.com/@nqbao/exposing-kubernetes-cluster-over-vpn-7a97267b320a" rel="nofollow noreferrer">Exposing Kubernetes cluster over VPN</a>.
It describes how to connect VPN node to kuberentes cluster or Kubernetes services.</p>
<p>You might be also interested in reading Kubernetes documentation regarding <a href="https://kubernetes.io/docs/setup/multiple-zones/" rel="nofollow noreferrer">Running in Multiple Zones</a>.
Also <a href="https://itnext.io/kubernetes-multi-cluster-networking-made-simple-c8f26827813" rel="nofollow noreferrer">Kubernetes multi-cluster networking made simple</a>, which explains different use cases of VPNs across number of clusters and is strongly encouraging to use IPv6 instead of IPv4.</p>
<blockquote>
<p>Why use IPv6? Because “<em>we could assign a — public — IPv6 address to EVERY ATOM ON THE SURFACE OF THE EARTH, and still have enough addresses left to do another 100+ earths</em>” [<a href="https://itknowledgeexchange.techtarget.com/whatis/ipv6-addresses-how-many-is-that-in-numbers/" rel="nofollow noreferrer">SOURCE</a>]</p>
</blockquote>
<p>Lastly <a href="https://improbable.io/games/blog/introducing-kedge-a-fresh-approach-to-cross-cluster-communication" rel="nofollow noreferrer">Introducing kEdge: a fresh approach to cross-cluster communication</a>, which seems to make live easier and helps with configuration and maintenance of VPN services between clusters.</p>
