[Atlas] Authentication failed for running compact command on oplog.rs with atlasAdmin role

[Kyle_Yoon]

Hi.
I use MongoDB Atlas M20 instance.
I had an issue with huge oplog size(50GB) with storage auto scale option enabled.
So I turned off auto scaling and set Maximum Oplog Size as 990MB to prevent oplog size going to large.
Next, I wanted to run compact command on oplog collection to make disk size smaller but failed to run with authentication failed message.

{
	"message" : "not authorized on local to execute command { compact: 'oplog.rs', $clusterTime...

I found related articles but nobody seems to have an authentication issue like me.

Mongodb Atlas compact oplog.rs

Hello, I am facing some issues with my installation on MongoDB Atlas. I have an M10 cluster with mongo 4.4. This cluster needs to be configured under minimum requirements, with an M10 and 10GB of space. Something happened and the cluster storage autoscaled to 14GB (i forgot to deactivate the cluster storage autoscaling). The culprit of the storage consumption was the oplog.rs collection, on the local database. I successfully reduced the size of the oplog collection from the Atlas console (Clu…

Can anyone give me an advice?

[Kyle_Yoon]

This is a more detailed status of my instance.

VERSION

5.0.15

REGION

AWS / Tokyo (ap-northeast-1)

CLUSTER TIER

M20 (General)

TYPE

Replica Set - 3 nodes

[Ramachandra_Tummala]

Atlas admin role may not be having privilege to run compact command
May be you have to create a custom role giving explicit privileges/actions

[Jason_Tran]

You can try dbAdmin@local to see if that works for you.