Applicability of Standards Track MIBs to Management of World Wide Web Servers
draft-kalbfleisch-www-track-mibs-00

INTERNET DRAFT               WWW Track MIBs                June 9, 1996

                 Applicability of Standards Track MIBs to
                   Management of World Wide Web Servers

                <draft-kalbfleisch-www-track-mibs-00.txt>

                          Carl W. Kalbfleisch
                       OnRamp Technologies, Inc.
                            cwk@onramp.net

                             June, 9 1996

                         Status of this Memo

  This document is an Internet-Draft.  Internet-Drafts are working
  documents of the Internet Engineering Task Force (IETF), its
  areas, and its working groups.  Note that other groups may also
  distribute working documents as Internet-Drafts.

  Internet-Drafts are draft documents valid for a maximum of six
  months and may be updated, replaced, or obsoleted by other
  documents at any time.  It is inappropriate to use Internet-
  Drafts as reference material or to cite them other than as
  ``work in progress.''

  To learn the current status of any Internet-Draft, please check
  the ``1id-abstracts.txt'' listing contained in the Internet-
  Drafts Shadow Directories on ftp.is.co.za (Africa),
  nic.nordu.net (Europe), munnari.oz.au (Pacific Rim),
  ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast).

1. Abstract

  This document was produced at the request of the Network Management
  Area Director following the HTTP-MIB BOF at the 35th IETF meeting
  to report on the applicability of the existing standards track
  MIBs to management of WWW servers.

  Requirements for management of a World Wide Web (WWW) server are
  presented.  The applicable existing standards track MIBs are then
  examined.  Finally, an analysis of the additional groups of MIB
  attributes that are needed to meet the requirements is presented.

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2. Overview

  The World Wide Web (WWW) is a network of information, accessible
  via a simple easy to use interface.  The information is often
  presented in HyperText or multi-media.  The information is
  provided by servers which are located all around the world.
  The usability of the web depends largely on the performance of
  these servers. WWW servers are typically monitored through log files.
  This becomes a difficult task when a single organization is
  responsible for a number of servers. Since many organizations
  currently use the Internet Standard SNMP to manage their network
  devices, it is desirable to treat these WWW servers as additional
  devices within this framework. This will allow a single Network
  Management Station (NMS) to automate the management of a number of
  WWW servers as well as the entire enterprise. Defining a standard for
  this purpose allows a single management application to manage a
  number of servers from a variety of vendors.  Additionally, a formal
  definition of what has to be managed and how to manage it tends to
  lead to integrated and improved performance and fault management.

  Content providers are interested in the access statistics and
  configuration of their sites. The content provider may be the same or
  a different organization than the one that maintains the server as a
  whole. It may be possible to realize the new paradigm of "Customer
  Network Management" to provide this information to the content
  provider. This means that there exists a distinct organization
  different than the network operations center that is also interested
  in the management information from a device. Customer network
  management is desirable to allow each content provider on a server
  to access information about his own documents independent of the
  rest.

  Various organizations may be interested in SNMP manageable WWW
  clients and proxies as well. At this time, our focus is on WWW
  servers. A natural extension to this work could be a framework for
  managing WWW Clients and general information retrieval systems
  like WWW proxies, NNTP, GOPHER, FTP and WAIS.  The focus of this
  document remains the management of WWW servers.

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3. Requirements

  WWW servers can be viewed from several perspectives when assigning
  management responsibilities.  For the sake of discussion, these
  perspectives are named the Operational Model and the Service Model.
  The Operational Model views WWW servers as computers with hardware,
  disk, OS and web server software.  This model represents the actual
  resources that make up the machine so that it can be monitored from
  the perspective of resource utilization.  The Service Model views the
  WWW server as a black box that simply handles the responses to
  requests from clients located on the web.

  The two models compliment each other while providing distinct
  information about the server.  Members of the organization
  responsible for the WWW server, may be interested in one and/or
  both of the management models.  For this reason, the management
  information should be scalable, for one or both models to be
  implemented independent of the other.

  With this in mind, the requirements for WWW server management
  can are summarized below by expanding upon those generated at the
  HTTP-MIB BOF.

3.1  Operational Model Requirements

3.1.1. Host specific and Application Monitoring

  This includes monitoring the utilization of CPU, disk and network
  capacity.

3.1.2. Dependencies among applications.

  Some systems implement a number of services within a single piece of
  code. Others use multiple pieces of code to implement the same set of
  services. Because of this, dependencies develop among processes.
  These dependencies become critical when a particular process needs to
  be stopped, restarted or reconfigured. These dependencies need to be
  defined within the management information so that management
  applications can operate the systems correctly.

3.1.3. Error generation and reporting

  The WWW server generally reports errors via logging facilities.  The
  format of the log file is not well defined.  It is required that a
  standard facility for error reporting be utilized.

3.1.4. Capacity planning

  It is required to obtain statistics which can be used for capacity
  planning purposes. This includes planning for increased network
  bandwidth, computing power, disk space, number of concurrent server
  threads, etc.

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3.1.5. Log Digester

  WWW servers generally report status information by data generated in
  Common Log Format [1].  This information needs to be preserved as
  attributes in a MIB to facilitate remote monitoring providing a
  standard way to represent and retrieve the management information.

3.2. Service Model Requirements

3.2.1. Retrieval services

  Retrieval services are an abstract decoupling the information space
  from the underlying transport mechanism.  The goal at this time is
  to focus on the requirements for management of WWW servers. There
  may be considerable overlap with other types of servers like (FTP,
  NNTP, GOPHER and WAIS).  The term "retrieval services" is used here
  to retain this abstraction.  It is required to get statistics about
  the usage and performance of the retrieval services.

3.2.2. Document information store -- managing documents.

  Information from a WWW server can be static (a file) or dynamic
  (the output of some processing).  Management of these two types
  of information sources range from maintaining access statistics
  and access permissions to verifying the operational status of all
  applications that provide the dynamic information.

3.2.3. Server configuration.

  It is desirable to be able to centralize configuration management of
  the servers within an enterprise.

3.2.4. Server Control.

  WWW servers generally need to be controlled in regards to starting
  and stopping them as well as rotating log files.

3.2.5. Quality of Service

  Provide an indication of the quality of service the WWW server
  is providing.

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4. Relationship to existing IETF efforts

  In general, a WWW server is made up of or depends upon the following
  components:

        -a general purpose workstation running some operating system
        -http server software to answers requests from the network
        -various support routines like CGI programs or external
         applications (like DBMS) used to access information
        -a document store on one or more storage devices

  The health and performance of each of the above components is of
  interest when managing a WWW server.

  There are a number of standards track MIB modules that are of
  interest to the above list of items.  This list includes MIB-II [2],
  Host Resources MIB [3], Network Service Monitoring MIB [4] and
  Application MIB [5].

  This creates an impressive list of attributes to be implemented.  A
  definition of various levels of management of a WWW server is
  desired so that the implementor may scale his implementation in
  chunks which may include various components of each section.  For
  instance, this may allow customer network management without
  requiring the other groups being implemented.

4.1. MIB-II [2]

  MIB-II defines the managed objects which should be contained within
  TCP/IP based devices.

  The WWW server should support the applicable portions of MIB-II.
  This set probably includes, as a minimum, the following groups:
  system, interfaces, udp, icmp, tcp and snmp.

4.2. Host Resources MIB [3]

  This MIB defines a uniform set of objects useful for the management
  of host computers independently of the operating system, network
  services, or any software application.

  The MIB is structured as six groups; each specified as either
  "mandatory" or "optional".  If ANY "optional" group of the MIB is
  implemented, then ALL "mandatory" groups of the MIB must also be
  implemented.  This may cause implementation problems for some
  developers since many of these attributes require intimate knowledge
  of the OS.

  The groups defined by the MIB are:

        -System Group                           Mandatory
        -Storage Group                          Mandatory
        -Device Group                           Mandatory

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                -device types
                -device table
                -processor table
                -network table
                -printer table
                -disk storage table
                -partition table
                -file-system table
                -file-system types
        -Running Software Group                 Optional
        -Running Software Performance Group     Optional
        -Installed Software Group               Optional

  The system group provides general status information about the host.
  The storage and device groups define the information about the
  configuration and status of the resources which compose the host.
  It defines the resources which make up a generic host system and how
  they relate to each other.  Much of this information is useful for
  managing various aspects of a WWW server, like the file system and
  CPU utilization.  This information is useful for meeting the
  operational requirements. Much of this information is however more
  detailed than many WWW server managers require for service level
  requirements.

  The remaining groups define software components which are installed
  and/or running on the host.  Performance information is defined which
  extends that defined for each running process.  Unfortunately, the
  mapping between running software and installed software is difficult
  since it is related by a foreign key (Product ID) which does not
  appear to be required to exist in either table [6]. There is no
  provision to represent a group of processes which together perform
  some task (IE an application made up of multiple processes). The
  Applications MIB WG plans to address these deficiencies.

4.3. Network Services Monitoring MIB [4]

  This MIB is one of three documents produced by the MADMAN (Message
  And Directory MANagement) Working group.  It defines a set of general
  purpose attributes which would be appropriate for a range of
  applications that provide network services.  This definition is from
  the perspective of the service without considering the implementation
  in terms of host computers or processes.  Attributes provide
  statistics and status on the in-bound and out-bound associations that
  are currently active, and which have been active.

  This MIB is intended to be the minimum set of attributes common
  across a number of Network Service Applications.  Additional
  attributes are to be defined as necessary to manage specific network
  service applications.  WWW servers clearly fall into the category of
  network service applications.  All attributes in this MIB are
  relevant to WWW servers.

  The MIB consists of two tables:

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        -applTable                  Mandatory
        -assocTable                 Optional

  The applTable describes applications that provide network services
  and keeps statistics of the current number of active associations and
  the total number of associations since application initialization.
  The assocTable contains more detailed information about active
  associations.

  The other two MIBs defined by MADMAN, MTA MIB [7] and DSA MIB [8],
  are not relevant to the management of WWW services.  They do,
  however, demonstrate how to extend the Network Services Monitoring
  MIB for a specific set of applications.

4.4. Application MIB [5]

  The Application MIB WG is defining two separate MIBs: the sysApplMib
  and the applMib.  The first defines attributes that can be monitored
  without instrumenting the applications.  The second will define
  additional attributes requiring application instrumentation.

  The sysApplMIB allows for the description of applications as a
  collection of executables, and files installed and executing on a
  host computer. The objects support configuration, fault and
  performance management of some of the basic attributes of application
  software.

  The groups defined in the sysApplMIB are:

        -System Application Installed Group     Mandatory
                -sysApplInstalledTable
                -sysApplCfgElmtTable

        -System Application Run Group           Mandatory
                -sysApplRunTable
                -SysApplPastRunTable
                -sysApplElmtRunTable
                -sysApplElmtPastRunTable

  The sysApplInstalledTable captures what applications are installed on
  a particular host and the sysApplCfgElmtTable provides information
  regarding the executables and non executable files which collectively
  compose the application. The sysApplRunTable contains the application
  instances which are currently running and the sysApplPastRunTable
  contains a history about applications which have previously executed
  on the host. The sysApplElmtRunTable contains the process instances
  which are currently running and sysApplElmtPastRunTable contains a
  history about processes which have previously executed on the host.

  It should be noted that two implementations of the same set of
  network services may each define a different set of processes and
  files within this MIB.  Ultimately enough management information is
  needed so that these different implementations can at least be

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  managed similarly.

  WWW servers fall into the general category of application software.
  Therefore the attributes of this MIB are applicable if the process
  level detail is requested to meet the Operational Model requirements.

  The Application MIB WG is to resolve the problems described above
  with the relationship between the running and installed software of
  the Host Resources MIB.

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5. Summary of Existing Standards Track MIBs

  The existing MIBs are largely orthogonal as demonstrated by the
  diagram below.  Host Resources relates network information to the
  interfaces defined in MIB-II.  The system application MIB relates its
  running element table to the equivalent entry in the Host Resources
  running software table.

  It should be noted that the running software of the Host Resources
  includes ALL software running on the host, while the running element
  table of the system application MIB only includes "interesting"
  processes of monitored applications.

  In the diagram below, "Other Services", "Application Specific MIBs"
  and "Application MIB" represent work to be done or in progress.

                          +---------------+
                          |  Application  |
                          | Specific MIBs |
                          +---------------+
                                 |
  +--------+ +---+ +---+  +---------------+
  |Other   | |MTA| |DSA|  |  Application  |
  |services| |MIB| |MIB|  |      MIB      |
  +--------+ +---+ +---+  +---------------+
      |        |     |           |
  +--------------------+  +---------------+  +--------------+  +------+
  |  Network Services  |  |    System     |  |Host Resources|  |MIB-II|
  |   Monitoring MIB   |  |Application MIB|--|     MIB      |--|      |
  +--------------------+  +---------------+  +--------------+  +------+

  The stack of MIBs above "Network Services Monitoring MIB" represent
  monitoring from the Service Model.  The other stacks represent
  monitoring from the Operational Model.  Neither of these stacks goes
  to the level of specific detail for any application. The author is of
  the opinion that HTTP or Web Server specific MIBs would exist at the
  top of each stack to represent the service and implementation view of
  the server respectively.  There should be a relationship between
  these two perspectives defined so that the correlations between the
  two perspectives is possible.  This relationship would be useful for
  general application and service monitoring in addition to just web
  servers.  However, it is not of specific interest to either the
  MADMAN WG or the Application MIB WG. It is therefore suggested that
  such a relationship is defined in a general case outside of either
  of those groups that would be applicable for WWW servers as well as
  for other application to service mappings.

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6. Definition of additional attributes

  The existing MIB attributes meet the Operational Model Requirement
  for tracking information specific to a host.  Specifically, MIB-II,
  Host Resources and the Applications MIB address these items. The
  Network Services MIB addresses a portion of the service model
  requirement for the decoupling of the information space from the
  transport mechanism.

  Several sets of additional attributes are needed to meet the
  remaining requirements. These additional attributes may be generally
  applicable to other network information retrieval services (like FTP,
  NNTP, GOPHER and WAIS) as well as client and proxy management.
  Management of these services is not the scope of this document.

  These additional attributes can be classified as:

  1) Definition of relationship between the Network Services Monitoring
     and Application MIBs.  This allows the functional organization of
     the server to be known.  It allows the management application to
     understand the effect of restarting specific processes on the
     services provided.  This addresses the Operational Model
     requirement to model dependencies between applications.

  2) Additions to generic Network Services Monitoring MIB. A draft [9]
     has already been circulated due to the work of a mailing list and
     a sample implementation.  These attributes list a summary at the
     service level of the configuration and the health of the server.
     From this, performance metrics can be observed.  In addition, the
     health of the server in terms of data timeouts is known.  These
     attributes address the requirement for Operational Model tracking
     of specific activity and the requirement for Service Model
     retrieval services.

  3) Document storage and access statistics are needed to address
     service model requirements.

  4) Additions to Application MIB are required to address server
     configuration requirements in the service model.

  5) Error and fault management attributes are required to address
     requirements for tracking specific activity of the web server.

  6) Configuration and Control are items that may be able to be defined
     in a general way within the applications MIB.  If not, a specific
     definition would be required here.

  Of the items listed above, (1) is needed on a general basis.  The
  others appear to the author as WWW server specific unless the scope
  of the work is opened to WWW clients and proxies as well as other
  services (like NNTP, FTP, GOPHER and WAIS).

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7. Usage Scenarios

  The example scenario will be a single host computer which implements
  WWW services using the "virtual domain" concept.  In this model, a
  single host performs as the WWW server for one or more addresses.
  For the purpose of example, we will specify that there are three
  domains being serviced from this host whose WWW servers are:

        -www.a.com
        -www.b.com
        -www.c.com

  Some implementations may implement these services as one set of
  processes that handle requests for each of the addresses.  Others
  may implement these services as a set of processes for each address.
  This means that the relationship defined between the Network Services
  Monitoring MIB and Application MIB components of the management
  information may vary between different implementations of the same
  configuration.

  MIB-II and Host Resources would provide the information about the
  host including the CPU, disk and network.  The Host Resource running
  table provide information on the processes in the system.

  There would be an entry in the Network Services Monitoring applTable
  for each virtual domain.  In addition, the assocTable shows which
  connections are currently active.  An extension to the association
  table would be helpful to provide information as to what is being
  transmitted.

  The sysApplMib would have entries in its installed software tables
  for the web server software and each "interesting" component.  This
  should include the server binary, CGI programs, configuration files
  and possibly the server log files.  Depending on the implementation
  of the server, the processes for each domain may show up in the same
  or different running software tables.

  Additional information as described in the previous section would
  round out the management information that would be available for
  the WWW server.

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8. Conclusion

  A number of currently defined attributes are useful for management
  of a WWW server. Specifically, MIB-II and Host Resources should be
  considered for monitoring the health of the machine in terms of
  host and network configuration and capacity.  The Network Services
  Monitoring MIB and the Application MIBs provide a general framework
  to represent the components of the WWW server from both a service and
  implementation perspective.  The Network Services Monitoring MIB
  suggests that extensions are necessary to cover specific network
  application monitoring. A set of such attributes can be well defined
  to provide status information of the WWW server.  The Application MIB
  suggests similar extensions.  Some of these attributes may be generic
  to all applications, and thus be implemented within the scope of the
  applMib. It is the opinion of this author that there will still
  remain specific instrumentation for WWW servers that can not, and
  should not, be covered in the Network Services Monitoring and
  Application MIBs.

  Since the Network Services Monitoring MIB and the Applications MIB
  represent orthogonal efforts of management, it is desirable to
  define the relationship between the two in a standard way.  This
  definition is probably more than a simple pointer from one table to
  another. Since it is outside the scope of either of those efforts, it
  is this author's opinion that that definition could and should be
  addressed within the scope of defining management of a specific
  application (IE WWW servers). This defintion although defined for
  a particular application, should be useful in a general way to
  describe the relationship between the Network Services Monitoring
  MIB and the Applications MIB.

  Additional attributes are needed in order to meet all of the
  requirements specified in this document.  An IETF standard would
  prevent independent developments of this effort in many enterprise
  MIBs.  It also allows management applications to control servers from
  multiple vendors.  It is likely that as the work in this area
  progresses, the management information will be useful for other
  Network Information Retrieval services (like FTP, GOPHER, WAIS and
  NNTP) as well.

  Finally, the Operational Model and Service Model Requirements lead
  to two main uses of the management information.  Design of the MIB
  including the usage of the existing MIBs should allow one or the
  other or both of these models to be implemented in a standard way.
  This may be desirable depending specifically on the audience of the
  data, the cost of instrumentation and the resources of the system.

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9. References

 [1] Anonymous, "Logging in the W3C httpd",
     http://www.w3.org/hypertext/WWW/Daemon/User/Config/Logging.html,
     W3C, July 1995

 [2] McCloghrie, K., and M. Rose, Editors, "Management Information
     Base for Network Management of TCP/IP-based internets: MIB-
     II", STD 17, RFC 1213, Hughes LAN Systems, Performance
     Systems International, March 1991.

 [3] Grillo, P., and S. Waldbusser, "Host Resources MIB", RFC 1514,
     Network Innovations, Intel Corporation, Carnegie Mellon
     University, September 1993

 [4] Kille, S., and N. Freed, "Network Services Monitoring MIB",
     RFC 1565, ISODE Consortium, Innosoft, January 1994

 [5] Saperia, J., C. Krupczak, R. Sturm, and J. Weinstock, "Definition
     of Managed Objects for Applications",
     draft-ietf-applmib-sysapplmib-02.txt, BGS Systems, Empire
     Technologies, Enterprise Management Professional Services,
     Bellcore, May 1996

 [6] Krupczak, C. and S. Waldbusser, "Applicability of Host Resources
     MIB to Application Management", Empire Technologies, Inc.,
     International Network Services, October 1995.

 [7] Kille, S., and N. Freed, "Mail Monitoring MIB", RFC 1566, ISODE
     Consortium, Innosoft, January 1994

 [8] Mansfield, G., and S. Kille, "X.500 Directory Monitoring MIB",
     RFC 1567, AIC Systems Laboratory, ISODE Consortium, January 1994

 [9] Hazewinkel, H., E. van Hengstum, A. Pras, "Definitions of Managed
     Objects for HTTP", draft-hazewinkel-httpmib-00.txt, University of
     Twente, April 1996

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10. Acknowledgments

  This document was produced at the request of the Network Management
  Area Director following the HTTP-MIB BOF at the 35th IETF meeting
  to report on the applicability of the existing standards track
  MIBs to management of WWW servers.

  The author gratefully acknowledges the comments of the following
  individuals:

            Ned Freed, ned@innosoft.com
                Innosoft, Inc.

            Harrie Hazewinkel, hazewink@cs.utwente.nl
                University of Twente

            Cheryl Krupczak, cheryl@empiretech.com
                Empire Technologies, Inc.

            Rui Meneses, rui.meneses@jrc.it
                Centre for Earth Observation

            Jon Saperia, saperia@bgs.com
                BGS Systems, Inc.

            Juergen Schoenwaelder, schoenw@cs.utwente.nl
                University of Twente

            Chris Wellens, chrisw@iwl.com
                InterWorking Labs, Inc.

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11. Further Information

  The current status of the HTTP-MIB standardization can be found on
  the World Wide Web at <URL:http://http-mib.onramp.net/>.  An email
  list is in operation for discussion of this topic.  To subscribe,
  send email to "http-mib-request@onramp.net" with the message body
  of "subscribe HTTP-MIB".

12. Security Considerations

  Security issues are not discussed in this memo.

13. Authors' Address

  Carl W. Kalbfleisch
  OnRamp Technologies, Inc.
  Email: cwk@onramp.net
  1950 Stemmons Frwy
  2026 INFOMART
  Dallas, TX 75207, USA               Tel: (214) 672-7246
  cwk@onramp.net                      Fax: (214) 672-7275

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Table of Contents

  1.     Abstract.................................................1
  2.     Overview.................................................1
  3.     Requirements.............................................2
  3.1    Operational Model Requirements...........................3
  3.1.1. Host specific and Application Monitoring.................3
  3.1.2. Dependencies among applications..........................3
  3.1.3. Error generation and reporting...........................3
  3.1.4. Capacity planning........................................3
  3.1.5. Log Digester.............................................3
  3.2.   Service Model Requirements...............................4
  3.2.1. Retrieval services.......................................4
  3.2.2. Document information store -- managing documents.........4
  3.2.3. Server configuration.....................................4
  3.2.4. Server Control...........................................4
  3.2.5. Quality of Service.......................................4
  4.     Relationship to existing IETF efforts....................4
  4.1.   MIB-II [2]...............................................5
  4.2.   Host Resources MIB [3]...................................5
  4.3.   Network Services Monitoring MIB [4]......................6
  4.4.   Application MIB [5]......................................7
  5.     Summary of Existing Standards Track MIBs.................8
  6.     Definition of additional attributes......................9
  7.     Usage Scenarios.........................................10
  8.     Conclusion..............................................11
  9.     References..............................................12
  10.    Acknowledgments.........................................13
  11.    Further Information.....................................14
  12.    Security Considerations.................................15
  13.    Authors' Address........................................15

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