From a7cdfccf38caed80c08abca1d3bd2d54f3c840fb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Czern=C3=BD?= <pczerny@opennebula.systems>
Date: Tue, 26 Jan 2021 11:28:07 +0100
Subject: [PATCH] F #1048: Unique VM identification (for KVM) (#700)

---
 include/NebulaUtil.h           |  5 +++++
 src/common/NebulaUtil.cc       | 22 ++++++++++++++++++++++
 src/vm/VirtualMachine.cc       |  2 +-
 src/vm/VirtualMachineParser.cc | 17 ++++++++++++++---
 src/vmm/LibVirtDriverKVM.cc    |  8 ++++++++
 5 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/include/NebulaUtil.h b/include/NebulaUtil.h
index ba724f50d1..0407e7c40d 100644
--- a/include/NebulaUtil.h
+++ b/include/NebulaUtil.h
@@ -327,6 +327,11 @@ namespace one_util
         return output;
     }
 
+    /**
+     * Generates a new uuid
+     */
+    std::string uuid();
+
 } // namespace one_util
 
 #endif /* _NEBULA_UTIL_H_ */
diff --git a/src/common/NebulaUtil.cc b/src/common/NebulaUtil.cc
index 9310a6abf1..c319b5eadf 100644
--- a/src/common/NebulaUtil.cc
+++ b/src/common/NebulaUtil.cc
@@ -428,3 +428,25 @@ void one_util::split_unique(const string& st, char delim, set<string>& res)
         res.insert(str);
     }
 }
+
+/* -------------------------------------------------------------------------- */
+/* -------------------------------------------------------------------------- */
+
+string one_util::uuid()
+{
+    // Generate from random numbers to avoid adding a dependency
+    ostringstream oss;
+
+    oss.fill('0');
+    oss << hex
+        << setw(4) << random<short uint>()
+        << setw(4) << random<short uint>()
+        << "-" << setw(4) << random<short uint>()
+        << "-" << setw(4) << ((random<short uint>() & 0x0fff) | 0x4000)
+        << "-" << setw(4) << random<short uint>() % 0x3fff + 0x8000
+        << "-" << setw(4) << random<short uint>()
+        << setw(4) << random<short uint>()
+        << setw(4) << random<short uint>();
+
+    return oss.str();
+}
\ No newline at end of file
diff --git a/src/vm/VirtualMachine.cc b/src/vm/VirtualMachine.cc
index cb1612c343..e9354946a1 100644
--- a/src/vm/VirtualMachine.cc
+++ b/src/vm/VirtualMachine.cc
@@ -2767,7 +2767,7 @@ void VirtualMachine::get_public_clouds(const string& pname, set<string> &clouds)
 /* -------------------------------------------------------------------------- */
 
 static std::map<std::string,std::vector<std::string>> UPDATECONF_ATTRS = {
-    {"OS", {"ARCH", "MACHINE", "KERNEL", "INITRD", "BOOTLOADER", "BOOT", "KERNEL_CMD", "ROOT", "SD_DISK_BUS"} },
+    {"OS", {"ARCH", "MACHINE", "KERNEL", "INITRD", "BOOTLOADER", "BOOT", "KERNEL_CMD", "ROOT", "SD_DISK_BUS", "UUID"} },
     {"FEATURES", {"PAE", "ACPI", "APIC", "LOCALTIME", "HYPERV", "GUEST_AGENT",
          "VIRTIO_SCSI_QUEUES"} },
     {"INPUT", {"TYPE", "BUS"} },
diff --git a/src/vm/VirtualMachineParser.cc b/src/vm/VirtualMachineParser.cc
index 9d4babc3a8..5cbdb9ca63 100644
--- a/src/vm/VirtualMachineParser.cc
+++ b/src/vm/VirtualMachineParser.cc
@@ -187,15 +187,18 @@ int VirtualMachine::parse_os(string& error_str)
 
     if ( num == 0 )
     {
-        return 0;
+        os = new VectorAttribute("OS");
+        obj_template->set(os);
     }
     else if ( num > 1 )
     {
         error_str = "Only one OS attribute can be defined.";
         return -1;
     }
-
-    os = dynamic_cast<VectorAttribute *>(os_attr[0]);
+    else
+    {
+        os = dynamic_cast<VectorAttribute *>(os_attr[0]);
+    }
 
     if ( os == 0 )
     {
@@ -212,6 +215,14 @@ int VirtualMachine::parse_os(string& error_str)
 
     rc = set_os_file(os, "INITRD", Image::RAMDISK, error_str);
 
+    string uuid = os->vector_value("UUID");
+
+    if (uuid.empty())
+    {
+        uuid = one_util::uuid();
+        os->replace("UUID", uuid);
+    }
+
     if ( rc != 0 )
     {
         return -1;
diff --git a/src/vmm/LibVirtDriverKVM.cc b/src/vmm/LibVirtDriverKVM.cc
index 5fbc54db6d..1274ca18cf 100644
--- a/src/vmm/LibVirtDriverKVM.cc
+++ b/src/vmm/LibVirtDriverKVM.cc
@@ -614,6 +614,14 @@ int LibVirtDriver::deployment_description_kvm(
 
     file << "\t<title>" << vm->get_name() << "</title>" << endl;
 
+    auto os = vm->get_template_attribute("OS");
+    auto uuid = os->vector_value("UUID");
+
+    if (!uuid.empty())
+    {
+        file << "\t<uuid>" << uuid << "</uuid>" << endl;
+    }
+
     // ------------------------------------------------------------------------
     // CPU & Memory
     // ------------------------------------------------------------------------