## Why
Ceph OSDs manage their own I/O ordering, so the kernel scheduler on the backing disks just adds overhead. The original intent was to set those disks to the `noop` scheduler. The whole OSD fleet (k8s + incus nodes) runs AlmaLinux 9 on blk-mq kernels (5.14), where the equivalent of `noop` is `none`.
## Changes
- Add `profiles::ceph::osd_scheduler`, rendering a udev rule from the `ceph_osd_devices` fact (PR #504) that pins `queue/scheduler` to `none` on each OSD disk.
- Reload udev and trigger the matched block devices so the setting applies immediately; the udev rule keeps it set across reboots and device re-add.
- No-op when the fact is absent/empty, so VMs and non-OSD hosts are untouched.
- Include the class from `profiles::ceph::osd` so it lands only on OSD hosts.
https://claude.ai/code/session_01JUoARVdmhxKQHyyyp1pxeT
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Co-authored-by: BenVincent <benvin@main.unkin.net>
Reviewed-on: #505
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>
## Summary
- Adds `Unkin::Ceph::Utils` facter module detecting ceph service instances via `systemctl list-units`, exposing `is_ceph_mon`, `is_ceph_mgr`, `is_ceph_mds`, `is_ceph_osd` booleans and a `ceph_services` hash of unit names
- Adds `profiles::ceph::mon`, `mgr`, `mds`, `osd` — each with `Boolean $ensure_running` that iterates discovered service instances and manages them as running and enabled
- Works across incus nodes (mon/mgr/mds/osd) and k8s compute/control nodes (osd only); verified on prodnxsr0001 which correctly reports `is_ceph_osd: true` and `ceph_services: {osd: [ceph-osd@5]}`
## Test plan
- [x] Noop deploy against prodnxsr0001.main.unkin.net passed cleanly
- [x] `ceph_services` fact returns correct service map
- [x] `is_ceph_osd` returns `True`, `is_ceph_mon` returns `False` as expected
- [x] Test on an incus/ceph node with mon/mgr/mds services
Reviewed-on: #459
unkinben