org.btrplace.scheduler.choco.constraint.mttr.VMPlacementUtils Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of scheduler-choco Show documentation

Implementation of the VM scheduler that use the Constraint Programming solver CHOCO to compute solutions.

The newest version!

/*
 * Copyright  2020 The BtrPlace Authors. All rights reserved.
 * Use of this source code is governed by a LGPL-style
 * license that can be found in the LICENSE.txt file.
 */

package org.btrplace.scheduler.choco.constraint.mttr;

import org.btrplace.model.Mapping;
import org.btrplace.model.VM;
import org.btrplace.scheduler.choco.ReconfigurationProblem;
import org.chocosolver.solver.variables.IntVar;

import java.util.HashMap;
import java.util.Map;


/**
 * Tools to ease the management of the VM placement.
 *
 * @author Fabien Hermenier
 */
public final class VMPlacementUtils {

    private VMPlacementUtils() {
    }

    /**
     * Map a map where keys are the placement variable of the future-running VMs
     * and values are the VM identifier.
     *
     * @param rp the problem
     * @return the resulting map.
     */
    public static Map makePlacementMap(ReconfigurationProblem rp) {
        Map m = new HashMap<>(rp.getFutureRunningVMs().size());
        for (VM vm : rp.getFutureRunningVMs()) {
            IntVar v = rp.getVMAction(vm).getDSlice().getHoster();
            m.put(v, vm);
        }
        return m;
    }

    /**
     * Check if a VM can stay on its current node.
     *
     * @param rp the reconfiguration problem.
     * @param vm the VM
     * @return {@code true} iff the VM can stay
     */
    public static boolean canStay(ReconfigurationProblem rp, VM vm) {
        Mapping m = rp.getSourceModel().getMapping();
        if (m.isRunning(vm)) {
            int curPos = rp.getNode(m.getVMLocation(vm));
            return rp.getVMAction(vm).getDSlice().getHoster().contains(curPos);
        }
        return false;
    }
}