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RFC 7666

Management Information Base for Virtual Machines Controlled by a Hypervisor

Pages: 52
Proposed Standard
Errata
Part 1 of 3 – Pages 1 to 8
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Top   ToC   RFC7666 - Page 1
Internet Engineering Task Force (IETF)                           H. Asai
Request for Comments: 7666                                Univ. of Tokyo
Category: Standards Track                                    M. MacFaden
ISSN: 2070-1721                                              VMware Inc.
                                                        J. Schoenwaelder
                                                       Jacobs University
                                                                K. Shima
                                           IIJ Innovation Institute Inc.
                                                                 T. Tsou
                                               Huawei Technologies (USA)
                                                            October 2015


            Management Information Base for Virtual Machines
                       Controlled by a Hypervisor

Abstract

This document defines a portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. In particular, this specifies objects for managing virtual machines controlled by a hypervisor (a.k.a. virtual machine monitor). Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7666.
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Copyright Notice

   Copyright (c) 2015 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. The Internet-Standard Management Framework . . . . . . . . . 3 3. Overview and Objectives . . . . . . . . . . . . . . . . . . . 3 4. Structure of the VM-MIB Module . . . . . . . . . . . . . . . 5 5. Relationship to Other MIB Modules . . . . . . . . . . . . . . 7 6. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 8 6.1. VM-MIB . . . . . . . . . . . . . . . . . . . . . . . . . 8 6.2. IANA-STORAGE-MEDIA-TYPE-MIB . . . . . . . . . . . . . . . 43 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 45 8. Security Considerations . . . . . . . . . . . . . . . . . . . 45 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 46 9.1. Normative References . . . . . . . . . . . . . . . . . . 46 9.2. Informative References . . . . . . . . . . . . . . . . . 47 Appendix A. State Transition Table . . . . . . . . . . . . . . . 49 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 51 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 52

1. Introduction

This document defines a portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. In particular, this specifies objects for managing virtual machines controlled by a hypervisor (a.k.a. virtual machine monitor). A hypervisor controls multiple virtual machines on a single physical machine by allocating resources to each virtual machine using virtualization technologies. Therefore, this MIB module contains information on virtual machines and their resources controlled by a hypervisor as well as information about a hypervisor's hardware and software.
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   The design of this MIB module has been derived from product-specific
   MIB modules -- namely, a MIB module for managing guests of the Xen
   hypervisor [Xen], a MIB module for managing virtual machines
   controlled by the VMware hypervisor [VMware], and a MIB module using
   the libvirt programming interface [libvirt] to access different
   hypervisors.  However, this MIB module attempts to generalize the
   managed objects to support other implementations of hypervisors.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2. The Internet-Standard Management Framework

For a detailed overview of the documents that describe the current Internet-Standard Management Framework, please refer to section 7 of RFC 3410 [RFC3410]. Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. MIB objects are generally accessed through the Simple Network Management Protocol (SNMP). Objects in the MIB are defined using the mechanisms defined in the Structure of Management Information (SMI). This memo specifies a MIB module that is compliant to the SMIv2, which is described in STD 58, RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580 [RFC2580].

3. Overview and Objectives

This document defines a portion of MIB for the management of virtual machines controlled by a hypervisor. This MIB module consists of the managed objects related to system and software information of a hypervisor, the list of virtual machines controlled by the hypervisor, and information of virtual resources allocated to virtual machines by the hypervisor. This document specifies four specific types of virtual resources that are common to many hypervisor implementations: processors (CPUs), memory, network interfaces (NICs), and storage devices. These managed objects are independent of the families of hypervisors or operating systems running on virtual machines.
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   +------------------------------------------------------------------+
   | +-------------------------------------------------+              |
   | | Virtual machine                                 |              |
   | |                                                 |              |
   | | +---------+ +---------+ +---------+ +---------+ | .......      |
   | | | Virtual | | Virtual | | Virtual | | Virtual | |              |
   | +-| CPU     |-| memory  |-| storage |-| NIC     |-+              |
   |   +---------+ +---------+ +---------+ +---------+                |
   |            Virtual resources                                     |
   |                   ^                                              |
   |                   | Allocation using virtualization technologies |
   |                   |                                              |
   |                   +-- Physical resources  ._____.                |
   |              +--------+    .--------.    /       \    +--^--+    |
   +- - - - - - - |        | - /________/| - *\_______/* - |     | - -+
   | Hypervisor   |  CPU   |   | Memory |/   | Storage |   | NIC |    |
   |              +--------+   +--------+     \_______/    +-----+    |
   |  +-----------------------+                                       |
   |  ||     MIB objects     ||                                       |
   |  +-----------------------+                                       |
   +------------------------------------------------------------------+

           Figure 1: An Example of a Virtualization Environment

   On the common implementations of hypervisors, a hypervisor allocates
   virtual resources from physical resources: virtual CPUs, virtual
   memory, virtual storage devices, and virtual network interfaces to
   virtual machines as shown in Figure 1.  Since the virtual resources
   allocated to virtual machines are managed by the hypervisor, the MIB
   objects are managed at the hypervisor.  In case that the objects are
   accessed through the SNMP, an SNMP agent is launched at the
   hypervisor to provide access to the objects.

   The objects are managed from the viewpoint of the operators of
   hypervisors, but not the operators of virtual machines; that is, the
   objects do not take into account the actual resource utilization on
   each virtual machine but rather the resource allocation from the
   physical resources.  For example, vmNetworkIfIndex indicates the
   virtual interface associated with an interface of a virtual machine
   at the hypervisor, and consequently, the 'in' and 'out' directions
   denote 'from a virtual machine to the hypervisor' and 'from the
   hypervisor to a virtual machine', respectively.  Moreover,
   vmStorageAllocatedSize denotes the size allocated by the hypervisor,
   but not the size actually used by the operating system on the virtual
   machine.  This means that vmStorageDefinedSize and
   vmStorageAllocatedSize do not take different values when the
   vmStorageSourceType is 'block' or 'raw'.
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   The objectives of this document are the following: 1) this document
   defines the MIB objects common to many hypervisors for the management
   of virtual machines controlled by a hypervisor, and 2) this document
   clarifies the relationship with other MIB modules for managing host
   computers and network devices.

4. Structure of the VM-MIB Module

The MIB module is organized into a group of scalars and tables. The scalars below 'vmHypervisor' provide basic information about the hypervisor. The 'vmTable' lists the virtual machines (guests) that are known to the hypervisor. The 'vmCpuTable' provides the mapping table of virtual CPUs to virtual machines, including CPU time used by each virtual CPU. The 'vmCpuAffinityTable' provides the affinity of each virtual CPU to a physical CPU. The 'vmStorageTable' provides the list of virtual storage devices and their mapping to virtual machines. In case that an entry in the 'vmStorageTable' has a corresponding parent physical storage device managed in 'vmStorageTable' of HOST-RESOURCES-MIB [RFC2790], the entry contains a pointer 'vmStorageParent' to the physical storage device. The 'vmNetworkTable' provides the list of virtual network interfaces and their mapping to virtual machines. Each entry in the 'vmNetworkTable' also provides a pointer 'vmNetworkIfIndex' to the corresponding entry in the 'ifTable' of IF-MIB [RFC2863]. In case that an entry in the 'vmNetworkTable' has a corresponding parent physical network interface managed in the 'ifTable' of IF-MIB, the entry contains a pointer 'vmNetworkParent' to the physical network interface.
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   Notation:

       +-------------+
       | vmOperState | : Finite state; the first line presents the
       |             |   'vmOperState', and the second line presents a
       +-------------+   notification generated if applicable.

       + - - - - - - +
       | vmOperState | : Transient state; first line presents the
       |             |   'vmOperState', and the second line presents a
       + - - - - - - +   notification generated if applicable.

       !               : Notification; a text followed by the symbol "!"
                         denotes a notification generated.

   =====================================================================

   +---------------+   + - - - - - - - -+     +------------+
   |  suspended(6) |<--|  suspending(5) |     |  paused(8) |
   | !vmSuspended  |   | !vmSuspending  |     | !vmPaused  |
   +---------------+   + - - - - - - - -+     +------------+
         |                ^                    ^
         |                |                    |
         v                |                    |
   + - - - - - - -+   +-------------+<----------+    + - - - - - - - +
   |  resuming(7) |-->|  running(4) |<-------------->|  migrating(9) |
   | !vmResuming  |   | !vmRunning  |                | !vmMigrating  |
   + - - - - - - -+   +-------------+                + - - - - - - - +
                          |      ^                        ^
                          |      |                        |
                          |      +-------------------+    |
                          |                          |    |
                          v                          v    v
                   + - - - - - - - - - +          +---------------+
                   |  shuttingdown(10) |--------->|  shutdown(11) |
                   | !vmShuttingdown   |          | !vmShutdown   |
                   + - - - - - - - - - +          +---------------+
                                                    ^      |
                                                    |      v !vmDeleted
                   +--------------+   + - - - - - - - -+  (Deleted from
                   |  crashed(12) |   |  preparing(3)  |   vmTable)
                   | !vmCrashed   |   |                |
                   +--------------+   + - - - - - - - -+

              Figure 2: State Transition of a Virtual Machine
Top   ToC   RFC7666 - Page 7
   The 'vmAdminState' and 'vmOperState' textual conventions define an
   administrative state and an operational state model for virtual
   machines.  Events causing transitions between major operational
   states will cause the generation of notifications.  Per virtual
   machine (per-VM) notifications (vmRunning, vmShutdown, vmPaused,
   vmSuspended, vmCrashed, vmDeleted) are generated if
   vmPerVMNotificationsEnabled is true(1).  Bulk notifications
   (vmBulkRunning, vmBulkShutdown, vmBulkPaused, vmBulkSuspended,
   vmBulkCrashed, vmBulkDeleted) are generated if
   vmBulkNotificationsEnabled is true(1).  The overview of the
   transition of 'vmOperState' by the write access to 'vmAdminState' and
   the notifications generated by the operational state changes are
   illustrated in Figure 2.  The detailed state transition is summarized
   in Appendix A.  Note that the notifications shown in this figure are
   per-VM notifications.  In the case of Bulk notifications, the prefix
   'vm' is replaced with 'vmBulk'.

   The bulk notification mechanism is designed to reduce the number of
   notifications that are trapped by an SNMP manager.  This is because
   the number of virtual machines managed by a bunch of hypervisors in a
   data center possibly becomes several thousands or more, and
   consequently, many notifications could be trapped if these virtual
   machines frequently change their administrative state.  The per-VM
   notifications carry more detailed information, but the scalability is
   a problem.  The notification filtering mechanism described in
   Section 6 of RFC 3413 [RFC3413] is used by the management
   applications to control the notifications.

5. Relationship to Other MIB Modules

The HOST-RESOURCES-MIB [RFC2790] defines the MIB objects for managing host systems. On systems implementing the HOST-RESOURCES-MIB, the objects of HOST-RESOURCES-MIB indicate resources of a hypervisor. Some objects of HOST-RESOURCES-MIB are used to indicate physical resources through indexes. On systems implementing HOST-RESOURCES-MIB, the 'vmCpuPhysIndex' points to the processor's 'hrDeviceIndex' in the 'hrProcessorTable'. The 'vmStorageParent' also points to the storage device's 'hrStorageIndex' in the 'hrStorageTable'. The IF-MIB [RFC2863] defines the MIB objects for managing network interfaces. Both physical and virtual network interfaces are required to be contained in the 'ifTable' of IF-MIB. The virtual network interfaces in the 'ifTable' of IF-MIB are pointed from the 'vmNetworkTable' defined in this document through a pointer 'vmNetworkIfIndex'. In case that an entry in the 'vmNetworkTable'
Top   ToC   RFC7666 - Page 8
   has a corresponding parent physical network interface managed in the
   'ifTable' of IF-MIB, the entry contains a pointer 'vmNetworkParent'
   to the physical network interface.

   The objects related to virtual switches are not included in the MIB
   module defined in this document though virtual switches MAY be placed
   on a hypervisor.  This is because the virtual network interfaces are
   the lowest abstraction of network resources allocated to a virtual
   machine.  Instead of including the objects related to virtual
   switches, for example, IEEE8021-BRIDGE-MIB [IEEE8021-BRIDGE-MIB] and
   IEEE8021-Q-BRIDGE-MIB [IEEE8021-Q-BRIDGE-MIB] could be used.

   The other objects related to virtual machines such as management IP
   addresses of a virtual machine are not included in this MIB module
   because this MIB module defines the objects common to general
   hypervisors, but they are specific to some hypervisors.  They may be
   included in the entLogicalTable of ENTITY-MIB [RFC6933].

   The SNMPv2-MIB [RFC3418] provides an object 'sysObjectID' that
   identifies the network management subsytem and an object 'sysUpTime'
   that reports the uptime of the network management portion of the
   system.  The HOST-RESOURCES-MIB [RFC2790] provides an object
   'hrSystemUptime' that reports the uptime of the host's operating
   system.  To complement these objects, the new 'vmHvUpTime' object
   reports the time since the hypervisor was last re-initialized, and
   the new 'vmHvObjectID' provides an identification of the hypervisor
   software.



(page 8 continued on part 2)

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