com.netflix.fenzo.ScaleDownOrderEvaluator Maven / Gradle / Ivy
/*
* Copyright 2017 Netflix, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.netflix.fenzo;
import java.util.Collection;
import java.util.List;
import java.util.Set;
/**
* A constraint evaluator that examines if VMs can be terminated, and in which order. It groups VMs into equivalence
* classes, and orders them according to their scale down priority. If a VM instance is missing in the returned list
* it means that it should not be terminated.
* The scale down order within an equivalence class is determined by {@link ScaleDownConstraintExecutor}.
*/
public interface ScaleDownOrderEvaluator {
/**
* Returns VMs grouped into equivalence classes ordered according to their scale down priority.
*
* @param candidates VMs to be terminated
* @return VMs in scale down order
*/
List> evaluate(Collection candidates);
}