# PSMDB cros site replication without MCS

**URL:** <https://forums.percona.com/t/psmdb-cros-site-replication-without-mcs/40369>\
**Category:** MongoDB\
**Created:** [March 18, 2026, 9:29am UTC](https://forums.percona.com/t/psmdb-cros-site-replication-without-mcs/40369 "2026-03-18T09:29:32Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![acelayir](https://avatars.discourse-cdn.com/v4/letter/a/e68b1a/32.png) [@acelayir](https://forums.percona.com/u/acelayir)\
**Post date:** [March 18, 2026, 9:29am UTC](https://forums.percona.com/t/psmdb-cros-site-replication-without-mcs/40369/1 "2026-03-18T09:29:32Z")

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Hi

We have 2 cluster on k8s env and we want to do cross site replication. In percona document MCS is described.

Is there a way to create cross site replication without MCS.

Regards

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**Author:** ![Ivan\_Groenewold](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/ivan_groenewold/32/6299_2.png) [@Ivan\_Groenewold](https://forums.percona.com/u/Ivan_Groenewold)\
**Post date:** [March 18, 2026, 10:58am UTC](https://forums.percona.com/t/psmdb-cros-site-replication-without-mcs/40369/2 "2026-03-18T10:58:48Z")

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Hi, technically it is possible but would be quite complicated. You will need to implement cross-cluster DNS resolution (probably ExternalDNS), as well as ensuring all nodes can reach each other’s services.

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**Author:** ![acelayir](https://avatars.discourse-cdn.com/v4/letter/a/e68b1a/32.png) [@acelayir](https://forums.percona.com/u/acelayir)\
**Post date:** [March 19, 2026, 8:13am UTC](https://forums.percona.com/t/psmdb-cros-site-replication-without-mcs/40369/3 "2026-03-19T08:13:09Z")

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Hi @Ivan_Groenewold

Thanks for your response. We exposed services as nodeport on both side like following

➜ ~ k5 get services psmdb-db-rs0-0  
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE  
psmdb-db-rs0-0 NodePort 10.x.x.x 27017:30304/TCP 18h  
➜ ~ k4 get services psmdb-db-rs0-0  
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE  
psmdb-db-rs0-0 NodePort 10.x.x.x 27017:31619/TCP 18h

over node ip both cluster is accessible to each other. Which kind of dns entry we should define? Can we use host alias to handle it?

Regards

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**Author:** ![Ivan\_Groenewold](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/ivan_groenewold/32/6299_2.png) [@Ivan\_Groenewold](https://forums.percona.com/u/Ivan_Groenewold)\
**Post date:** [April 9, 2026, 10:50am UTC](https://forums.percona.com/t/psmdb-cros-site-replication-without-mcs/40369/4 "2026-04-09T10:50:13Z")

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Sorry I had missed your reply. You should be able to make it work with host aliases, however the Operator may reassign NodePorts on pod recreation if you haven’t pinned them. You will need to patch the services after each deploy or use a fixed nodePort. Also you will need to manually generate TLS certificates.

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**Author:** ![acelayir](https://avatars.discourse-cdn.com/v4/letter/a/e68b1a/32.png) [@acelayir](https://forums.percona.com/u/acelayir)\
**Post date:** [April 9, 2026, 11:04am UTC](https://forums.percona.com/t/psmdb-cros-site-replication-without-mcs/40369/5 "2026-04-09T11:04:13Z")

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Hi Ivan  
Do you know any MCP solution which work on openshift?  
Regards