Changes to the error message displayed during the removal of public templates that are used

Author: erikbocks

server/src/main/java/com/cloud/template/TemplateManagerImpl.java

@@ -219,7 +219,6 @@
 import com.cloud.vm.VmDetailConstants;
 import com.cloud.vm.dao.UserVmDao;
 import com.cloud.vm.dao.VMInstanceDao;
-import com.google.common.base.Joiner;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 
@@ -1384,8 +1383,15 @@ public boolean deleteTemplate(DeleteTemplateCmd cmd) {
             vmInstanceVOList = _vmInstanceDao.listNonExpungedByTemplate(templateId);
         }
         if(!cmd.isForced() && CollectionUtils.isNotEmpty(vmInstanceVOList)) {
-            final String message = String.format("Unable to delete Template: %s because Instance: [%s] are using it.",  template, Joiner.on(",").join(vmInstanceVOList));
-            logger.warn(message);
+            String message = String.format("Unable to delete template with ID %s, because there are VM instances using it.", templateId);
+            String instancesListMessage = String.format(" Instances list: [%s].", StringUtils.join(vmInstanceVOList, ","));
+
+            logger.warn("{}{}", message, instancesListMessage);
+
+            if (_accountMgr.isRootAdmin(caller.getAccountId())) {
+                message += instancesListMessage;
+            }
+
             throw new InvalidParameterValueException(message);
         }