node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/CapacityPolicies.java


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// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.hosted.provision.provisioning;

import com.yahoo.config.provision.Capacity;
import com.yahoo.config.provision.ClusterSpec;
import com.yahoo.config.provision.Environment;
import com.yahoo.config.provision.SystemName;
import com.yahoo.config.provision.Zone;

import com.yahoo.config.provision.Flavor;
import com.yahoo.config.provision.NodeFlavors;

import java.util.Arrays;
import java.util.Optional;

/**
 * Defines the policies for assigning cluster capacity in various environments
 *
 * @author bratseth
 */
public class CapacityPolicies {

    private final Zone zone;
    private final NodeFlavors flavors;

    public CapacityPolicies(Zone zone, NodeFlavors flavors) {
        this.zone = zone;
        this.flavors = flavors;
    }

    public int decideSize(Capacity requestedCapacity, ClusterSpec.Type clusterType) {
        int requestedNodes = ensureRedundancy(requestedCapacity.nodeCount(), clusterType, requestedCapacity.canFail());
        if (requestedCapacity.isRequired()) return requestedNodes;

        switch(zone.environment()) {
            case dev : case test : return 1;
            case perf : return Math.min(requestedCapacity.nodeCount(), 3);
            case staging: return requestedNodes <= 1 ? requestedNodes : Math.max(2, requestedNodes / 10);
            case prod : return requestedNodes;
            default : throw new IllegalArgumentException("Unsupported environment " + zone.environment());
        }
    }

    public Flavor decideFlavor(Capacity requestedCapacity, ClusterSpec cluster) {
        // for now, always use the requested flavor if a docker flavor is requested
        Optional<String> requestedFlavor = requestedCapacity.flavor();
        if (requestedFlavor.isPresent() &&
            flavors.getFlavorOrThrow(requestedFlavor.get()).getType() == Flavor.Type.DOCKER_CONTAINER)
            return flavors.getFlavorOrThrow(requestedFlavor.get());

        String defaultFlavorName = zone.defaultFlavor(cluster.type());
        if (zone.system() == SystemName.cd)
            return flavors.getFlavorOrThrow(requestedFlavor.orElse(defaultFlavorName));
        switch(zone.environment()) {
            case dev : case test : case staging : return flavors.getFlavorOrThrow(defaultFlavorName);
            default : return flavors.getFlavorOrThrow(requestedFlavor.orElse(defaultFlavorName));
        }
    }

    /**
     * Whether or not the nodes requested can share physical host with other applications.
     * A security feature which only makes sense for prod.
     */
    public boolean decideExclusivity(boolean requestedExclusivity) {
        return requestedExclusivity && zone.environment() == Environment.prod;
    }

    /**
     * Throw if the node count is 1 for container and content clusters and we're in a production zone
     *
     * @return the argument node count
     * @throws IllegalArgumentException if only one node is requested and we can fail
     */
    private int ensureRedundancy(int nodeCount, ClusterSpec.Type clusterType, boolean canFail) {
        if (canFail &&
                nodeCount == 1 &&
                Arrays.asList(ClusterSpec.Type.container, ClusterSpec.Type.content).contains(clusterType) &&
                zone.environment().isProduction())
            throw new IllegalArgumentException("Deployments to prod require at least 2 nodes per cluster for redundancy");
        return nodeCount;
    }

}