1 files changed, 80 insertions, 0 deletions
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/ResourceChange.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/ResourceChange.java
new file mode 100644
index 00000000000..c0cbb40d992
--- /dev/null
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/ResourceChange.java
@@ -0,0 +1,80 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.provision.autoscale;
+
+import com.yahoo.config.provision.ClusterSpec;
+import com.yahoo.config.provision.NodeResources;
+
+import java.time.Duration;
+
+/**
+ * A resource change.
+ *
+ * @author bratseth
+ */
+public class ResourceChange {
+
+    private final AllocatableResources from, to;
+    private final ClusterModel model;
+
+    public ResourceChange(ClusterModel model, AllocatableResources to) {
+        this.from = model.current();
+        this.to = to;
+        this.model = model;
+    }
+
+    /** Returns the estimated total cost of this resource change (coming in addition to the "to" resource cost). */
+    public double cost() {
+        if (requiresRedistribution()) return toHours(model.redistributionDuration()) * from.cost();
+        if (requiresNodeReplacement()) return toHours(model.nodeReplacementDuration()) * from.cost();
+        return 0;
+    }
+
+    private boolean requiresRedistribution() {
+        if ( ! model.clusterSpec().type().isContent()) return false;
+        if (from.nodes() != to.nodes()) return true;
+        if (from.groups() != to.groups()) return true;
+        if (requiresNodeReplacement()) return true;
+        return false;
+    }
+
+    /** Returns true if the *existing* nodes of this needs to be replaced in this change. */
+    private boolean requiresNodeReplacement() {
+        var fromNodes = from.advertisedResources().nodeResources();
+        var toNodes = to.advertisedResources().nodeResources();
+
+        if (model.isExclusive()) {
+            return ! fromNodes.equals(toNodes);
+        }
+        else {
+            if ( ! fromNodes.justNonNumbers().equalsWhereSpecified(toNodes.justNonNumbers())) return true;
+            if ( ! canInPlaceResize()) return true;
+            return false;
+        }
+    }
+
+    private double toHours(Duration duration) {
+        return duration.toMillis() / 3600000.0;
+    }
+
+    private boolean canInPlaceResize() {
+        return canInPlaceResize(from.nodes(), from.advertisedResources().nodeResources(),
+                                to.nodes(), to.advertisedResources().nodeResources(),
+                                model.clusterSpec().type(), model.isExclusive(), from.groups() != to.groups());
+    }
+
+    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;
+    }
+
+}