# Single rs possible?

**URL:** <https://forums.percona.com/t/single-rs-possible/39295>\
**Category:** Percona Operator for MongoDB\
**Created:** [September 8, 2025, 3:02am UTC](https://forums.percona.com/t/single-rs-possible/39295 "2025-09-08T03:02:30Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![dalu](https://avatars.discourse-cdn.com/v4/letter/d/7bcc69/32.png) [@dalu](https://forums.percona.com/u/dalu)\
**Post date:** [September 8, 2025, 3:02am UTC](https://forums.percona.com/t/single-rs-possible/39295/1 "2025-09-08T03:02:30Z")

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## Description:

Is installing a single rs possible? Not 3 replicas, 1.

I don’t want to waste the limited resources of the cluster. I have rdb underlying with 3 replicas, so I don’t need another layer of 3 nodes consuming at least 2 vcpu and 2GB RAM.

I could imagine 2 instances and 1 arbiter, or simply have just 1 instance, configured as a rs, because changelogs require it to be a rs.

## Steps to Reproduce:

[Step-by-step instructions on how to reproduce the issue, including any specific settings or configurations]

## Version:

8.0.12

## Logs:

[If applicable, include any relevant log files or error messages]

## Expected Result:

[What the user expected to see or happen before the issue occurred]

## Actual Result:

[What actually happened when the user encountered the issue]

## Additional Information:

[Include any additional information that could be helpful to diagnose the issue, such as browser or device information]

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<div class="post-metadata">

**Author:** ![yunus.uyanik](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/yunus.uyanik/32/19250_2.png) [@yunus.uyanik](https://forums.percona.com/u/yunus.uyanik)\
**Post date:** [September 18, 2025, 6:34am UTC](https://forums.percona.com/t/single-rs-possible/39295/2 "2025-09-18T06:34:01Z")

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Yes, it is possible. Some people use this method to feed their debezzium since debezzium feeds from the oplog, and the oplog is only available with a replication setup.,  
You can just follow the below and skip the other nodes:

> **[Convert a Standalone Self-Managed mongod to a Replica Set - Database Manual -...](https://www.mongodb.com/docs/manual/tutorial/convert-standalone-to-replica-set/)**
>
> Convert a standalone mongod to a replica set for production, ensuring redundancy. Check security before exposing the cluster.

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<div class="post-metadata">

**Author:** ![Stateros](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/stateros/32/2490_2.png) [@Stateros](https://forums.percona.com/u/Stateros)\
**Post date:** [September 23, 2025, 6:14pm UTC](https://forums.percona.com/t/single-rs-possible/39295/3 "2025-09-23T18:14:29Z")

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UnsafeFlags section in cr.yaml may help you to avoid any manual manipulation: [Custom Resource options - Percona Operator for MongoDB](https://docs.percona.com/percona-operator-for-mongodb/operator.html#unsafe-flags-section)