## What this PR does
Add linstor-scheduler-extender for optimal pod placement on nodes with
LINSTOR storage.
### How it works
The linstor-scheduler consists of two components:
#### 1. Scheduler Extender
A custom Kubernetes scheduler that works alongside the default
kube-scheduler. When a pod requests LINSTOR-backed storage, the
scheduler extender communicates with the LINSTOR controller to find
nodes that have local replicas of the requested volumes, prioritizing
placement on nodes with existing data to minimize network traffic.
#### 2. Admission Webhook
A MutatingWebhookConfiguration that automatically sets `schedulerName:
linstor-scheduler` on pods that use LINSTOR CSI driver volumes. This
ensures that only pods with LINSTOR PVCs are routed through the custom
scheduler, while all other pods continue using the default scheduler.
The webhook inspects pod creation requests and checks if any of the
pod's PVCs use a StorageClass with the LINSTOR CSI provisioner
(`linstor.csi.linbit.com`). If so, it mutates the pod spec to use the
linstor-scheduler.
### Components
- `linstor-scheduler` package in `packages/system/linstor-scheduler/`
- PackageSource definition in
`packages/core/platform/sources/linstor-scheduler.yaml`
- Integration into `paas-full` and `distro-full` bundles
### Upstream PRs
- https://github.com/piraeusdatastore/helm-charts/pull/67 — fix:
KubeSchedulerConfiguration v1 support for Kubernetes 1.25+
- https://github.com/piraeusdatastore/helm-charts/pull/68 — feat:
admission webhook support with cert-manager
- https://github.com/piraeusdatastore/helm-charts/pull/69 — fix chart
template issues
### Release note
```release-note
[linstor] Add linstor-scheduler for optimal pod placement on nodes with local LINSTOR replicas. Includes admission webhook that automatically routes pods using LINSTOR CSI volumes to the custom scheduler.
```
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **New Features**
* Added LINSTOR scheduler component to the platform, packaged as a Helm
chart and installable package.
* Includes admission webhook, scheduler extender, autoscaling support,
pod disruption budget, RBAC and service account integration, and Helm
test hooks.
* **Documentation**
* Added chart README and default configuration values for easy
deployment and customization.
<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
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