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Network Working Group                                    C. KalbfleischRequest for Comments: 2039                    OnRamp Technologies, Inc.Category: Informational                                   November 1996Applicablity of Standards Track MIBs to Management of World WideWeb ServersStatus of this Memo   This memo provides information for the Internet community.  This memo   does not specify an Internet standard of any kind.  Distribution of   this memo is unlimited.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.Table of Contents1.     Abstract.................................................12.     Overview.................................................23.     Requirements.............................................33.1    Operational Model Requirements...........................33.1.1. Host specific and Application Monitoring.................33.1.2. Dependencies among applications..........................33.1.3. Error generation and reporting...........................33.1.4. Capacity planning........................................43.1.5. Log Digester.............................................43.2.   Service Model Requirements...............................43.2.1. Retrieval services.......................................43.2.2. Document information store -- managing documents.........43.2.3. Server configuration.....................................43.2.4. Server Control...........................................43.2.5. Quality of Service.......................................44.     Relationship to existing IETF efforts....................54.1.   MIB-II [2]...............................................54.2.   Host Resources MIB [3]...................................54.3.   Network Services Monitoring MIB [4]......................64.4.   Application MIB [5]......................................7Kalbfleisch                  Informational                      [Page 1]

RFC 2039                     WWW Track MIBs                November 19965.     Summary of Existing Standards Track MIBs.................86.     Definition of additional attributes......................97.     Usage Scenarios.........................................118.     Conclusion..............................................119.     References..............................................1310.    Acknowledgments.........................................1311.    Further Information.....................................1412.    Security Considerations.................................1413.    Authors' Address........................................142. 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.Kalbfleisch                  Informational                      [Page 2]

RFC 2039                     WWW Track MIBs                November 19963. 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 Requirements3.1.1. 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.Kalbfleisch                  Informational                      [Page 3]

RFC 2039                     WWW Track MIBs                November 19963.1.4. 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.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 Requirements3.2.1. 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.Kalbfleisch                  Informational                      [Page 4]

RFC 2039                     WWW Track MIBs                November 19964. 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.Kalbfleisch                  Informational                      [Page 5]

RFC 2039                     WWW Track MIBs                November 1996   The groups defined by the MIB are:      -System Group                           Mandatory      -Storage Group                          Mandatory      -Device Group                           Mandatory                -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 provideKalbfleisch                  Informational                      [Page 6]

RFC 2039                     WWW Track MIBs                November 1996   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:           -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.Kalbfleisch                  Informational                      [Page 7]

RFC 2039                     WWW Track MIBs                November 1996   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   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.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.Kalbfleisch                  Informational                      [Page 8]

RFC 2039                     WWW Track MIBs                November 1996   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.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.Kalbfleisch                  Informational                      [Page 9]

RFC 2039                     WWW Track MIBs                November 1996   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).Kalbfleisch                  Informational                     [Page 10]

RFC 2039                     WWW Track MIBs                November 19967. 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.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 frameworkKalbfleisch                  Informational                     [Page 11]

RFC 2039                     WWW Track MIBs                November 1996   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.Kalbfleisch                  Informational                     [Page 12]

RFC 2039                     WWW Track MIBs                November 19969. 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", Work in Progress. [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", Work in Progress.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.Kalbfleisch                  Informational                     [Page 13]

RFC 2039                     WWW Track MIBs                November 1996   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.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) 672-7275Kalbfleisch                  Informational                     [Page 14]