public static boolean canInPlaceResize(int fromCount, NodeResources fromResources,
                                           int toCount, NodeResources toResources,
                                           ClusterSpec.Type type, boolean exclusive, boolean hasTopologyChange) {
        if (exclusive) return false; // exclusive resources must match the host

        // Never allow in-place resize when also changing topology or decreasing cluster size
        if (hasTopologyChange || toCount < fromCount) return false;

        // Do not allow increasing cluster size and decreasing node resources at the same time for content nodes
        if (type.isContent() && toCount > fromCount && !toResources.satisfies(fromResources.justNumbers()))
            return false;

        return true;
    }
Returns true if the *existing* nodes of this needs to be replaced in this change.
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/ResourceChange.java