CentOS Stream 9 – Common Problem 246 – Diagnosis and Fix

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Files owned by nobody on NFSv4

Environment & Reproduction

Client and server idmap domains disagree on CS9 NFSv4.

Root Cause Analysis

rpc.idmapd uses default localdomain while server expects a real domain.

Quick Triage

ls -ln on mount shows nobody/nogroup despite valid UIDs.

Step-by-Step Diagnosis

Run: nfsidmap -d; cat /etc/idmapd.conf; rpc.idmapd -v -fS.

Solution – Primary Fix

Set Domain = in /etc/idmapd.conf on client and server; restart nfs-idmapd.

Solution – Alternative Approaches

Disable id mapping with sec=sys when uid namespaces align across all hosts.

Verification & Acceptance Criteria

Files appear owned by the correct user after fresh mount.

Rollback Plan

Revert /etc/idmapd.conf and restart services.

Prevention & Hardening

Manage idmapd via Ansible templating tied to AD domain.

Related Errors & Cross-Refs

Pairs with NFS permission denied and stale file handle.

Related tutorial: View the step-by-step tutorial for centos-stream-9.

View all centos-stream-9 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

idmapd.conf(5) and nfsidmap(8).