KubeVirt Descheduler Plugins

Out-of-tree KubeVirt-aware plugins for the Kubernetes descheduler.

This repository is consumed by openshift/descheduler as a statically-linked Go module. It is maintained by the OpenShift Virtualization team independently of the upstream descheduler release cycle.

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Plugins

Plugin	Extension points	Purpose
KubevirtMigrationAware	Filter, PreEvictionFilter	Prevents eviction of virt-launcher pods while a VM live-migration is in progress and applies an exponential-backoff cooldown after migrations complete.

See each plugin's own README for configuration details, tuning guidance, and operational metrics.

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Usage

Consumers import the root package and call Register once during plugin setup:

import kubevirtplugins "github.com/openshift-virtualization/kubevirt-descheduler-plugins"

func RegisterDefaultPlugins(registry pluginregistry.Registry) {
    // ... other plugins ...
    kubevirtplugins.Register(registry)
}

Calling Register adds every plugin in this repository to the registry. Adding a new plugin to this repo does not require changing the import or the call site in the downstream descheduler.

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Development

Prerequisites

• Go 1.25+
• A local checkout of openshift/descheduler

Running tests

go test ./plugins/...

The go.mod replace directive pins sigs.k8s.io/descheduler to a specific commit of the openshift/descheduler fork. If you need to test against a local descheduler checkout instead, override the replace directive:

go mod edit -replace sigs.k8s.io/descheduler=/path/to/openshift/descheduler
go test ./plugins/...

Adding a new plugin

1. Create plugins/<pluginname>/ with the plugin implementation.
2. Add a pluginregistry.Register(...) call for it in register.go.
3. Add a row to the table above and a plugins/<pluginname>/README.md.

No changes to the downstream descheduler carry commit are required.

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Repository structure

.
├── register.go              # root package — exposes Register(registry)
├── plugins/
│   └── kubevirtmigrationaware/
│       ├── README.md
│       └── *.go
└── .github/workflows/
    └── test.yml

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CI

Unit tests run on every pull request via GitHub Actions (see .github/workflows/test.yml). The workflow checks out this repository, sets up Go, and runs go build, go vet, and go test ./plugins/....

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License

Apache 2.0 — see LICENSE.