Overview

Ceph Reef (18.x) marked several features as deprecated in preparation for Squid and future releases. Understanding these deprecations helps you plan migrations before forced removal breaks workloads.

Check Deprecation Warnings

Ceph surfaces deprecation warnings in the health output:

kubectl -n rook-ceph exec -it deploy/rook-ceph-tools -- ceph health detail | grep -i deprecat

Review the Ceph log for deprecation notices:

kubectl -n rook-ceph logs deploy/rook-ceph-mon-a | grep -i deprecated

Key Deprecated Features in Reef

Legacy CephFS MDS Affinity

The old MDS affinity configuration using mds_standby_for_name is deprecated:

# Check if old affinity settings are in use
kubectl -n rook-ceph exec -it deploy/rook-ceph-tools -- ceph config dump | grep mds_standby

Migrate to the new fs set standby_count_wanted approach:

kubectl -n rook-ceph exec -it deploy/rook-ceph-tools -- ceph fs set myfs standby_count_wanted 1

RBD Mirroring Bootstrap Token Format

The old bootstrap token format for RBD mirroring is deprecated. Generate a new token:

kubectl -n rook-ceph exec -it deploy/rook-ceph-tools -- rbd mirror pool peer bootstrap create \
  --site-name primary mypool

Legacy FileStore OSD Backend

The FileStore OSD backend is deprecated in Reef. All OSDs should use BlueStore:

# Check OSD backend type
kubectl -n rook-ceph exec -it deploy/rook-ceph-tools -- ceph osd metadata | jq '.[].osd_objectstore' | sort | uniq -c

If any OSDs still report filestore, plan a migration to bluestore by reprovisioning those OSDs.

Audit Your Configuration

Generate a full config dump to spot deprecated options:

kubectl -n rook-ceph exec -it deploy/rook-ceph-tools -- ceph config dump > config-dump.txt
grep -E "(deprecated|legacy|old)" config-dump.txt

Remove deprecated config keys proactively:

kubectl -n rook-ceph exec -it deploy/rook-ceph-tools -- ceph config rm global old_option_name

Update Rook CRDs

Check your CephCluster and related CRDs for deprecated fields in the Rook API:

kubectl get cephcluster rook-ceph -n rook-ceph -o yaml | grep -i deprecated

Compare against the Rook v1.14+ CRD reference to identify removed fields.

Summary

Ceph Reef deprecates several legacy features including old MDS standby settings, bootstrap token formats, and the FileStore OSD backend. Use ceph health detail and ceph config dump to audit your cluster, and proactively migrate deprecated configurations before upgrading to Squid to prevent service disruptions.