Problem Statement/Rationale

If we try to restore a second database into a populated cluster, the restore fails with an IllegalOperation error message

Steps to Reproduce

• Set up 2 sharded clusters
• Create 2 databases in the origin cluster
• Create roles and users in these databases (not in admin)
• mongodump a single database with the flag --dumpDbUsersAndRoles
• mongodump another database with the flag --dumpDbUsersAndRoles
• mongorestore the first database with the flag --restoreDbUsersAndRoles
• mongorestore the second database with the flag --restoreDbUsersAndRoles -> error happens here

2025-06-17T18:18:07.927+0000  dropping preexisting temporary collection admin.tempusers
2025-06-17T18:18:07.928+0000  Failed: restore error: error dropping preexisting temporary collection tempusers: (IllegalOperation) Cannot drop collection in 'admin' database in sharded cluster
2025-06-17T18:18:07.928+0000  20000 document(s) restored successfully. 0 document(s) failed to restore. 

Expected Results

Same and different databases can be restored as many times as necessary without errors

Actual Results

Error thrown, data for the second database was restored, but users were not

Additional Notes

Tests were done today with MongoDB CE v8.0.10 and mongodb-database-tools v100.12.2

Workaround

Connect directly to the configuration replica primary node and drop the temp collections:

db.getSiblingDB("admin").getCollection("tempusers").drop()
db.getSiblingDB("admin").getCollection("temproles").drop()