YARN-9370. Added logging for recovering assigned GPU devices.

            Contributed by Yesha Vora

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/linux/resources/gpu/GpuResourceAllocator.java

@@ -119,6 +119,7 @@ public class GpuResourceAllocator {
               + containerId);
     }
 
+    LOG.info("Starting recovery of GpuDevice for {}.", containerId);
     for (Serializable gpuDeviceSerializable : c.getResourceMappings()
         .getAssignedResources(GPU_URI)) {
       if (!(gpuDeviceSerializable instanceof GpuDevice)) {
@@ -146,7 +147,10 @@ public class GpuResourceAllocator {
       }
 
       usedDevices.put(gpuDevice, containerId);
+      LOG.info("ContainerId {} is assigned to GpuDevice {} on recovery.",
+          containerId, gpuDevice);
     }
+    LOG.info("Finished recovery of GpuDevice for {}.", containerId);
   }
 
   /**