Refactor: Skew computation independent of node prioritization

5 files changed, 43 insertions, 27 deletions

diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/Node.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/Node.java
index fa439e50fbd..3d502d2b3da 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/Node.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/Node.java
@@ -16,6 +16,7 @@ import com.yahoo.vespa.hosted.provision.node.Reports;
 import com.yahoo.vespa.hosted.provision.node.Status;
 
 import java.time.Instant;
+import java.util.Arrays;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
@@ -332,6 +333,19 @@ public final class Node {
         }
     }
 
+    /** Computes the allocation skew of a host node */
+    public static double skew(NodeResources totalHostCapacity, NodeResources freeHostCapacity) {
+        NodeResources all = totalHostCapacity.anySpeed();
+        NodeResources allocated = all.subtract(freeHostCapacity.anySpeed());
+
+        return new Mean(allocated.vcpu() / all.vcpu(),
+                                          allocated.memoryGb() / all.memoryGb(),
+                                          allocated.diskGb() / all.diskGb())
+                       .deviation();
+    }
+
+
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
@@ -389,4 +403,19 @@ public final class Node {
         }
     }
 
+    /** The mean and mean deviation (squared difference) of a bunch of numbers */
+    private static class Mean {
+
+        private final double mean;
+        private final double deviation;
+
+        private Mean(double ... numbers) {
+            mean = Arrays.stream(numbers).sum() / numbers.length;
+            deviation = Arrays.stream(numbers).map(n -> Math.pow(mean - n, 2)).sum() / numbers.length;
+        }
+
+        public double deviation() {  return deviation; }
+
+    }
+
 }
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/Rebalancer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/Rebalancer.java
new file mode 100644
index 00000000000..d2158dd08db
--- /dev/null
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/Rebalancer.java
@@ -0,0 +1,5 @@
+// Copyright 2019 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.provision.maintenance;
+
+public class Rebalancer {
+}
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/DockerHostCapacity.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/DockerHostCapacity.java
index 4eea36c342a..112f118705b 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/DockerHostCapacity.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/DockerHostCapacity.java
@@ -26,6 +26,12 @@ public class DockerHostCapacity {
         this.hostResourcesCalculator = Objects.requireNonNull(hostResourcesCalculator, "hostResourcesCalculator must be non-null");
     }
 
+    /** Returns the allocation skew of this host */
+    public double skew(Node host) {
+        NodeResources free = freeCapacityOf(host, false);
+        return Node.skew(host.flavor().resources(), free);
+    }
+
     int compareWithoutInactive(Node hostA, Node hostB) {
         int result = compare(freeCapacityOf(hostB, true), freeCapacityOf(hostA, true));
         if (result != 0) return result;
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/HostResourcesCalculator.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/HostResourcesCalculator.java
index 50aeb464e9f..c5808a53837 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/HostResourcesCalculator.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/HostResourcesCalculator.java
@@ -10,4 +10,5 @@ public interface HostResourcesCalculator {
 
     /** Calculates the resources that are reserved for host level processes and returns the remainder. */
     NodeResources availableCapacityOf(NodeResources hostResources);
+
 }
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/PrioritizableNode.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/PrioritizableNode.java
index d53e36b7501..d6ac5eb2c57 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/PrioritizableNode.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/PrioritizableNode.java
@@ -117,18 +117,8 @@ class PrioritizableNode implements Comparable<PrioritizableNode> {
     private double skewWith(NodeResources resources) {
         if (parent.isEmpty()) return 0;
 
-        NodeResources all = anySpeed(parent.get().flavor().resources());
-        NodeResources allocated = all.subtract(anySpeed(freeParentCapacity)).add(anySpeed(resources));
-
-        return new Mean(allocated.vcpu() / all.vcpu(),
-                        allocated.memoryGb() / all.memoryGb(),
-                        allocated.diskGb() / all.diskGb())
-                       .deviation();
-    }
-
-    /** We don't care about disk speed in calculations here */
-    private NodeResources anySpeed(NodeResources resources) {
-        return resources.withDiskSpeed(NodeResources.DiskSpeed.any);
+        NodeResources free = freeParentCapacity.anySpeed().subtract(resources.anySpeed());
+        return Node.skew(parent.get().flavor().resources(), free);
     }
 
     private boolean isInNodeRepoAndReserved() {
@@ -186,19 +176,4 @@ class PrioritizableNode implements Comparable<PrioritizableNode> {
         }
     }
 
-    /** The mean and mean deviation (squared difference) of a bunch of numbers */
-    private static class Mean {
-
-        private final double mean;
-        private final double deviation;
-
-        private Mean(double ... numbers) {
-            mean = Arrays.stream(numbers).sum() / numbers.length;
-            deviation = Arrays.stream(numbers).map(n -> Math.pow(mean - n, 2)).sum() / numbers.length;
-        }
-
-        public double deviation() {  return deviation; }
-
-    }
-
 }