Set balloon on startup.

org.jdrupes.vmoperator.runner.qemu/src/org/jdrupes/vmoperator/runner/qemu/QemuMonitor.java

@@ -68,7 +68,9 @@ public class QemuMonitor extends Component {
     @SuppressWarnings("PMD.UseConcurrentHashMap")
     private final Map<String, String> monitorMessages = new HashMap<>(Map.of(
         "connect", "{ \"execute\": \"qmp_capabilities\" }",
-        "powerdown", "{ \"execute\": \"system_powerdown\" }"));
+        "powerdown", "{ \"execute\": \"system_powerdown\" }",
+        "setBalloon", "{ \"execute\": \"balloon\", \"arguments\": "
+            + "{ \"value\": %d } }"));
 
     private Path socketPath;
     private int powerdownTimeout;
@@ -185,6 +187,16 @@ public class QemuMonitor extends Component {
         });
     }
 
+    /**
+     * Sets the current ram.
+     *
+     * @param amount the new current ram
+     */
+    public void setCurrentRam(Number amount) {
+        writeToMonitor(
+            String.format(monitorMessages.get("setBalloon"), amount));
+    }
+
     /**
      * Handle data from qemu monitor connection.
      *

org.jdrupes.vmoperator.runner.qemu/src/org/jdrupes/vmoperator/runner/qemu/Runner.java

@@ -108,7 +108,7 @@ import org.jgrapes.util.events.WatchFile;
  *     qemu --> monitor : FileChanged[monitor socket created] 
  * 
  *     monitor: entry/fire OpenSocketConnection
- *     monitor --> success: ClientConnected[for monitor]
+ *     monitor --> success: ClientConnected[for monitor]/set balloon value
  *     monitor -> error: ConnectError[for monitor]
  * }
  * 
@@ -129,7 +129,7 @@ import org.jgrapes.util.events.WatchFile;
  * 
  *     qemuPowerdown: entry/suspend Stop, send powerdown to qemu, start timer
  *     
- *     qemuPowerdown --> terminateProcesses: Closed[for monitor]/resume Stop
+ *     qemuPowerdown --> terminateProcesses: Closed[for monitor]/resume Stop,\ncancel Timer
  *     qemuPowerdown --> terminateProcesses: Timeout/resume Stop
  *     terminateProcesses --> terminated
  * }
@@ -445,6 +445,9 @@ public class Runner extends Component {
      */
     @Handler
     public void onQemuMonitorOpened(QemuMonitorOpened event) {
+        Optional.ofNullable(config.vm.currentRam)
+            .map(Configuration::parseMemory)
+            .ifPresent(qemuMonitor::setCurrentRam);
         state.set(State.RUNNING);
     }