Karmada Scheduler Edge Connect

Combined Karmada scheduler that replaces the stock karmada-scheduler with three additional plugins compiled in:

Plugin	Type	Source	What it does
CarbonScore	Filter + Score	karmada-carbon-scheduler	Filters/scores clusters by carbon intensity and renewable energy share via ClusterCarbonMetrics CRD
PredictionFilter	Filter	karmada-prediction-scheduler	Hard-rejects clusters with catastrophic predicted pressure (>95%) or extreme hotspots
PredictionScore	Score	karmada-prediction-scheduler	Ranks clusters by predicted future capacity with optional estimator fusion

All stock Karmada scheduler plugins remain active — these three are additive.

Full documentation lives under docs/. Start with docs/dependencies.md for what each plugin needs to actually do useful work (CRDs, collectors, prediction pipeline), then docs/getting-started/quickstart.md for installation and docs/how-to/enable-plugins-staged.md for the safe rollout sequence.

Why?

Karmada does not support chaining multiple scheduler binaries. A ResourceBinding is handled by exactly one scheduler. Running carbon and prediction as separate schedulers means workloads get one or the other, never both.

This repo compiles all plugins into a single binary that replaces the stock karmada-scheduler deployment so every workload benefits from all scheduling signals.

Architecture

┌─────────────────────────────────────────────────────┐
│              karmada-scheduler-edge-connect          │
│                                                     │
│  ┌─────────────┐  ┌──────────────────┐              │
│  │ Filter phase │  │ Score phase      │              │
│  │              │  │                  │              │
│  │ • built-ins  │  │ • built-ins      │              │
│  │ • CarbonScore│  │ • CarbonScore    │              │
│  │ • Prediction │  │ • PredictionScore│              │
│  │   Filter     │  │                  │              │
│  └──────┬───────┘  └────────┬─────────┘              │
│         │ AND               │ SUM                    │
│         ▼                   ▼                        │
│    candidates          ranked list                   │
└─────────────────────────────────────────────────────┘
         ▲                    ▲
         │                    │
  ClusterCarbonMetrics  ClusterPredictionState
  (carbon-data-collector)  (prediction-service)

Prerequisites

Both CRDs must be installed in the Karmada control plane:

• ClusterCarbonMetrics (API group carbon.edge-connect.eu)
• ClusterPredictionState (API group prediction.edge-connect.eu)

The plugins degrade gracefully if their CRDs are absent — they log a warning and allow all clusters through (fail-open).

Development

# Build locally
make build-local

# Run tests
make test

# Build Docker image (run from repo root — Dockerfile uses sibling dirs)
make docker-build

The module is self-contained: the carbon (pkg/apis/carbon) and prediction (pkg/apis/prediction) API types are vendored in-tree, so no replace directives or sibling checkouts are required.

Deployment

helm install karmada-scheduler chart/ \
  --namespace karmada-system \
  --set image.repository=<registry>/karmada-scheduler-edge-connect \
  --set image.tag=v0.1.0 \
  --set kubeconfig.existingSecret=karmada-kubeconfig

This deployment replaces the stock karmada-scheduler. Delete or scale down the original deployment first.

Configuration

CarbonScore plugin (env vars)

Variable	Default	Description
CARBON_WEIGHT	0.7	Weight for carbon intensity in score calculation
RENEWABLE_WEIGHT	0.3	Weight for renewable share in score calculation
MAX_CARBON_INTENSITY	200	Max gCO₂/kWh threshold for filter (0=disabled)
MIN_RENEWABLE_SHARE	0.0	Min renewable % threshold for filter (0=disabled)

PredictionScore plugin (env vars)

Variable	Default	Description
PREDICTION_SCORE_MODE	prediction_only	prediction_only or estimator_fusion
PREDICTION_SCORE_WEIGHT	30	Weight for prediction score
PREDICTION_HORIZON	10m	Prediction horizon (10m, 30m, 60m)
PREDICTION_ESTIMATOR_TIMEOUT	500ms	RPC timeout for estimator calls

Scheduler flags

Flag	Default	Description
--plugins	*,CarbonScore,PredictionFilter,PredictionScore	Enable all defaults + custom plugins
--enable-scheduler-estimator	true	Enable Karmada scheduler estimator
--leader-elect	true	HA leader election

Publication note

This repository is published as a result of the EU-funded project DTAG Beitrag zur Entwicklung eines Multi-Provider Edge-Cloud-Kontinuums (Deutsche Telekom IPCEI-CIS), part of the 8ra initiative. It is provided for publication and dissemination purposes and is effectively read-only: external contributions, pull requests, and issue-based collaboration are not accepted unless explicitly requested by the project consortium. See CONTRIBUTING.md and SECURITY.md.

License

Unless stated otherwise:

• Source code is licensed under the Apache License 2.0 — see LICENSE-CODE.
• Documentation and other textual materials are licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0) — see LICENSE-DOCS.

Attribution and consortium information are recorded in NOTICE. Third-party components are documented in THIRD-PARTY-NOTICES.md.

EU funding notice and disclaimer

Funded by the European Union – NextGenerationEU under Grant Agreement No. 13IPC005.

The views and opinions expressed are solely those of the author(s) and do not necessarily reflect the views of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them.

See EU-DISCLAIMER.md.