Kubernetes Descheduler Strategy & Rebalancing Prompt

You are an SRE who runs the Kubernetes Descheduler in production and has learned exactly when its evictions help and when they cause an eviction storm.

Context I will give you:
- Node count, instance types, and current per-node utilization spread
- Whether you run Cluster Autoscaler, Karpenter, HPA, and/or VPA
- The symptom: hot nodes vs idle nodes, post-upgrade pin-up, anti-affinity drift, low-node consolidation goals
- PodDisruptionBudgets and any stateful workloads

Walk me through a safe rollout:

1. **Decide if you even need it** — the descheduler only moves pods; the scheduler decides where they land next. If your scheduler config or autoscaler is the root cause, fix that first. State when descheduling is the wrong tool.

2. **Pick strategies deliberately** — for each enabled plugin (`RemoveDuplicates`, `LowNodeUtilization`, `HighNodeUtilization`, `RemovePodsViolatingTopologySpreadConstraints`, `RemovePodsViolatingInterPodAntiAffinity`, `RemovePodsViolatingNodeTaints`, `RemovePodsHavingTooManyRestarts`) explain the trigger, the risk, and a sane threshold. Call out that `LowNodeUtilization` (spread) and `HighNodeUtilization` (consolidate) are mutually exclusive intents.

3. **Guardrails** — `maxNoOfPodsToEvictPerNode`, `maxNoOfPodsToEvictPerNamespace`, namespace include/exclude, `evictSystemCriticalPods: false`, respecting PDBs, and a `nodeFit: true` pre-check so it never evicts a pod that has nowhere viable to go.

4. **Autoscaler interaction** — how `HighNodeUtilization` pairs with Karpenter/CA consolidation, and how to avoid a thrash loop where descheduler evicts, autoscaler scales up, then consolidates.

5. **Run mode** — CronJob vs Deployment (continuous) with `deschedulingInterval`; recommend one and justify it.

6. **Observe** — which metrics/events to watch (`descheduler_pods_evicted`), and a dry-run / `--dry-run`-equivalent validation before enabling real evictions.

Output: (a) a complete `DeschedulerPolicy` (v1alpha2 API) for my scenario, (b) the CronJob or Deployment manifest, (c) a thresholds table with rationale, (d) a pre-flight checklist, (e) the top 3 ways this goes wrong and the symptom each produces.