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/*
 * 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.transition;

import org.btrplace.model.Node;
import org.btrplace.model.NodeState;
import org.btrplace.plan.ReconfigurationPlan;
import org.btrplace.plan.event.ShutdownNode;
import org.btrplace.scheduler.SchedulerException;
import org.btrplace.scheduler.choco.ReconfigurationProblem;
import org.btrplace.scheduler.choco.extensions.FastIFFEq;
import org.btrplace.scheduler.choco.extensions.FastImpliesEq;
import org.btrplace.scheduler.choco.extensions.TaskMonitor;
import org.chocosolver.solver.Model;
import org.chocosolver.solver.Solution;
import org.chocosolver.solver.variables.BoolVar;
import org.chocosolver.solver.variables.IntVar;

/**
 * Model an action that allow a node to boot if necessary.
 * An estimation of the action duration must be provided through a
 * {@link org.btrplace.scheduler.choco.duration.ActionDurationEvaluator} accessible from
 * {@link org.btrplace.scheduler.choco.ReconfigurationProblem#getDurationEvaluators()} with the key {@code ShutdownNode.class}
 * 

* The action is modeled as follow: *

    *
  • Definition of the node state. If the node is offline, then no VMs can run on it: *
      *
    • {@link #getState()} = {0,1}
    • *
    • {@link #getState()} = 0 -> {@code btrplace.solver.choco.ReconfigurationProblem.getNbRunningVMs()[nIdx] = 0}
    • *
    *
  • *
  • The action duration equals 0 if the node stays online. Otherwise, it equals the evaluated action duration {@code d} * retrieved from {@link org.btrplace.scheduler.choco.ReconfigurationProblem#getDurationEvaluators()}: *
      *
    • {@link #getDuration()} = {0,d}
    • *
    • {@link #getDuration()} = {@link #getState()} * d
    • *
    *
  • *
  • The action starts and ends necessarily before the end of the reconfiguration problem. Their difference * equals the action duration. If the node stays online then the action starts and ends at moment 0. *
      *
    • {@link #getStart()} < {@link org.btrplace.scheduler.choco.ReconfigurationProblem#getEnd()}
    • *
    • {@link #getEnd()} < {@link org.btrplace.scheduler.choco.ReconfigurationProblem#getEnd()}
    • *
    • {@link #getEnd()} = {@link #getStart()} + {@link #getDuration()}
    • *
    *
  • *
  • The node can consume hosting VMs and the beginning of the reconfiguration plan. If the node goes offline, it stops hosting VMs at * the beginning of the action. Otherwise, it equals the end of the reconfiguration process so that it is always capable * of hosting VMs. *
      *
    • {@link #getHostingStart()} = {@link org.btrplace.scheduler.choco.ReconfigurationProblem#getStart()}
    • *
    • {@code T} = { {@link #getStart()}, {@link org.btrplace.scheduler.choco.ReconfigurationProblem#getEnd()} }; {@link #getHostingEnd()} = T[{@link #getState()}]
    • *
    *
  • *
*

* If the reconfiguration problem has a solution, a {@link org.btrplace.plan.event.ShutdownNode} action is inserted * into the resulting reconfiguration plan if the node is turned offline. * * @author Fabien Hermenier, Tu Dang */ public class ShutdownableNode implements NodeTransition { public static final String PREFIX = "shutdownableNode("; private final Node node; private final BoolVar isOnline; private final BoolVar isOffline; private final IntVar duration; private final IntVar end; private final IntVar hostingStart; private final IntVar hostingEnd; private final IntVar start; /** * Make a new model. * * @param rp the RP to use as a basis. * @param e the node managed by the action * @throws org.btrplace.scheduler.SchedulerException if an error occurred */ public ShutdownableNode(ReconfigurationProblem rp, Node e) throws SchedulerException { this.node = e; Model csp = rp.getModel(); /* - If the node is hosting running VMs, it is necessarily online - If the node is offline, it is sure it cannot host any running VMs */ if (rp.labelVariables()) { isOnline = csp.boolVar(rp.makeVarLabel(PREFIX, e, ").online")); } else { isOnline = csp.boolVar(""); } isOffline = isOnline.not(); csp.post(new FastImpliesEq(isOffline, rp.getNbRunningVMs().get(rp.getNode(e)), 0)); /* * D = {0, d} * D = St * d; */ int d = rp.getDurationEvaluators().evaluate(rp.getSourceModel(), ShutdownNode.class, e); if (rp.labelVariables()) { duration = csp.intVar(rp.makeVarLabel(PREFIX, e, ").duration"), new int[]{0, d}); } else { duration = csp.intVar(new int[]{0, d}); } csp.post(new FastIFFEq(isOnline, duration, 0)); //The moment of shutdown action consume /* As */ if (rp.labelVariables()) { start = rp.makeUnboundedDuration(PREFIX, e, ").start"); } else { start = rp.makeUnboundedDuration(); } //The moment of shutdown action end /* Ae */ if (rp.labelVariables()) { end = rp.makeUnboundedDuration(PREFIX, e, ").end"); } else { end = rp.makeUnboundedDuration(); } csp.post(csp.arithm(end, "<=", rp.getEnd())); /* Ae = As + D */ TaskMonitor.build(start, duration, end); //The node is already online, so it can host VMs at the beginning of the RP hostingStart = rp.getStart(); //The moment the node can no longer host VMs varies depending on its next state if (rp.labelVariables()) { hostingEnd = rp.makeUnboundedDuration(PREFIX, e, ").hostingEnd"); } else { hostingEnd = rp.makeUnboundedDuration(); } /* T = { As, RP.end} He = T[St] */ csp.post(csp.element(hostingEnd, new IntVar[]{start, rp.getEnd()}, isOnline, 0)); } @Override public boolean insertActions(Solution s, ReconfigurationPlan plan) { if (s.getIntVal(isOffline) == 1) { plan.add(new ShutdownNode(node, s.getIntVal(hostingEnd), s.getIntVal(end))); } return true; } @Override public String toString() { return "shutdownable(node=" + node + ", online=" + getState() + ")"; } @Override public Node getNode() { return node; } @Override public IntVar getStart() { return start; } @Override public IntVar getEnd() { return end; } @Override public IntVar getDuration() { return duration; } @Override public BoolVar getState() { return isOnline; } @Override public IntVar getHostingStart() { return hostingStart; } @Override public IntVar getHostingEnd() { return hostingEnd; } @Override public NodeState getSourceState() { return NodeState.ONLINE; } /** * The builder devoted to a online -> (online|offline) transition. */ public static class Builder extends NodeTransitionBuilder { /** * New builder */ public Builder() { super("shutdownable", NodeState.ONLINE); } @Override public NodeTransition build(ReconfigurationProblem r, Node n) throws SchedulerException { return new ShutdownableNode(r, n); } } }





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