Factor out allocation policy and add memory-aware policy

7 files changed, 60 insertions, 8 deletions

diff --git a/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/driver/VirtDriver.kt b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/driver/VirtDriver.kt
index 68b8e541..e68dd488 100644
--- a/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/driver/VirtDriver.kt
+++ b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/driver/VirtDriver.kt
@@ -24,8 +24,8 @@
 
 package com.atlarge.opendc.compute.virt.driver
 
-import com.atlarge.opendc.compute.core.Server
 import com.atlarge.opendc.compute.core.Flavor
+import com.atlarge.opendc.compute.core.Server
 import com.atlarge.opendc.compute.core.image.Image
 import com.atlarge.opendc.compute.core.monitor.ServerMonitor
 import com.atlarge.opendc.core.services.AbstractServiceKey
@@ -53,5 +53,12 @@ public interface VirtDriver {
      */
     public suspend fun getNumberOfSpawnedImages(): Int
 
+    /**
+     * Returns the available memory on the server managed by this driver.
+     *
+     * @return The available memory, in MB.
+     */
+    public suspend fun getAvailableMemory(): Long
+
     companion object Key : AbstractServiceKey<VirtDriver>(UUID.randomUUID(), "virtual-driver")
 }
diff --git a/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/driver/hypervisor/HypervisorVirtDriver.kt b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/driver/hypervisor/HypervisorVirtDriver.kt
index 9745b56c..4b23159f 100644
--- a/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/driver/hypervisor/HypervisorVirtDriver.kt
+++ b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/driver/hypervisor/HypervisorVirtDriver.kt
@@ -69,10 +69,6 @@ class HypervisorVirtDriver(
         return server
     }
 
-    override suspend fun getNumberOfSpawnedImages(): Int {
-        return vms.size
-    }
-
     internal inner class VmServerContext(
         override var server: Server,
         val monitor: ServerMonitor,
diff --git a/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/SimpleVirtProvisioningService.kt b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/SimpleVirtProvisioningService.kt
index 888364e2..309cfa83 100644
--- a/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/SimpleVirtProvisioningService.kt
+++ b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/SimpleVirtProvisioningService.kt
@@ -12,9 +12,11 @@ import com.atlarge.opendc.compute.virt.driver.VirtDriver
 import com.atlarge.opendc.compute.virt.driver.hypervisor.HypervisorImage
 import com.atlarge.opendc.compute.virt.driver.hypervisor.InsufficientMemoryOnServerException
 import com.atlarge.opendc.compute.virt.monitor.HypervisorMonitor
+import com.atlarge.opendc.compute.virt.service.allocation.AllocationPolicy
 import kotlinx.coroutines.launch
 
 class SimpleVirtProvisioningService(
+    public override val allocationPolicy: AllocationPolicy,
     private val ctx: SimulationContext,
     private val provisioningService: ProvisioningService,
     private val hypervisorMonitor: HypervisorMonitor
@@ -83,9 +85,7 @@ class SimpleVirtProvisioningService(
         for (imageInstance in imagesToBeScheduled) {
             println("Spawning $imageInstance")
 
-            val selectedNode = availableNodes.minBy {
-                it.server!!.serviceRegistry[VirtDriver.Key].getNumberOfSpawnedImages()
-            }
+            val selectedNode = availableNodes.minWith(allocationPolicy().thenBy { it.uid })
 
             try {
                 imageInstance.server = selectedNode?.server!!.serviceRegistry[VirtDriver.Key].spawn(
diff --git a/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/VirtProvisioningService.kt b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/VirtProvisioningService.kt
index fb087f9d..7770ec50 100644
--- a/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/VirtProvisioningService.kt
+++ b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/VirtProvisioningService.kt
@@ -3,11 +3,14 @@ package com.atlarge.opendc.compute.virt.service
 import com.atlarge.opendc.compute.core.Flavor
 import com.atlarge.opendc.compute.core.image.Image
 import com.atlarge.opendc.compute.core.monitor.ServerMonitor
+import com.atlarge.opendc.compute.virt.service.allocation.AllocationPolicy
 
 /**
  * A service for VM provisioning on a cloud.
  */
 interface VirtProvisioningService {
+    val allocationPolicy: AllocationPolicy
+
     /**
      * Submit the specified [Image] to the provisioning service.
      *
diff --git a/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/allocation/AllocationPolicy.kt b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/allocation/AllocationPolicy.kt
new file mode 100644
index 00000000..fc08aa87
--- /dev/null
+++ b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/allocation/AllocationPolicy.kt
@@ -0,0 +1,13 @@
+package com.atlarge.opendc.compute.virt.service.allocation
+
+import com.atlarge.opendc.compute.metal.Node
+
+/**
+ * A policy for selecting the [Node] an image should be deployed to,
+ */
+interface AllocationPolicy {
+    /**
+     * Builds the logic of the policy.
+     */
+    suspend operator fun invoke(): Comparator<Node>
+}
diff --git a/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/allocation/AvailableMemoryAllocationPolicy.kt b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/allocation/AvailableMemoryAllocationPolicy.kt
new file mode 100644
index 00000000..e02e2cef
--- /dev/null
+++ b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/allocation/AvailableMemoryAllocationPolicy.kt
@@ -0,0 +1,18 @@
+package com.atlarge.opendc.compute.virt.service.allocation
+
+import com.atlarge.opendc.compute.metal.Node
+import com.atlarge.opendc.compute.virt.driver.VirtDriver
+import kotlinx.coroutines.runBlocking
+
+/**
+ * Allocation policy that selects the node with the most available memory.
+ */
+class AvailableMemoryAllocationPolicy : AllocationPolicy {
+    override suspend fun invoke(): Comparator<Node> = Comparator { o1, o2 ->
+        runBlocking {
+            compareValuesBy(o1, o2) {
+                -it.server!!.serviceRegistry[VirtDriver.Key].getAvailableMemory()
+            }
+        }
+    }
+}
diff --git a/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/allocation/NumHostsAllocationPolicy.kt b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/allocation/NumHostsAllocationPolicy.kt
new file mode 100644
index 00000000..c5ee29c5
--- /dev/null
+++ b/opendc/opendc-compute/src/main/kotlin/com/atlarge/opendc/compute/virt/service/allocation/NumHostsAllocationPolicy.kt
@@ -0,0 +1,15 @@
+package com.atlarge.opendc.compute.virt.service.allocation
+
+import com.atlarge.opendc.compute.metal.Node
+import com.atlarge.opendc.compute.virt.driver.VirtDriver
+import kotlinx.coroutines.runBlocking
+
+class NumHostsAllocationPolicy : AllocationPolicy {
+    override suspend fun invoke(): Comparator<Node> = Comparator { o1, o2 ->
+        runBlocking {
+            compareValuesBy(o1, o2) {
+                it.server!!.serviceRegistry[VirtDriver.Key].getNumberOfSpawnedImages()
+            }
+        }
+    }
+}