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INNWATCH.CTL(5)
NAME
  innwatch.ctl - control Usenet supervision by innwatch

DESCRIPTION
  The file <pathetc in inn.conf>/innwatch.ctl is used to determine what
  actions are taken during the periodic supervisions by innwatch.

  The file consists of a series of lines; blank lines and lines beginning
  with a number sign (``#'') are ignored.  All other lines consist of seven
  fields, each preceded by a delimiting character:
       :label:state:condition:test:limit:command:reason

  The delimiter can be any one of several non-alphanumeric characters that
  does not appear elsewhere in the line; there is no way to quote it to
  include it in any of the fields.  Any of ``!'', ``,'', ``:'', ``@'', ``;'',
  or ``?'' is a good choice.  Each line can have a different delimiter; the
  first character on each line is the delimiter for that line.	White space
  surrounding delimiters, except before the first, is ignored, and does not
  form part of the fields, white space within fields is permitted.  All
  delimiters must be present.

  The first field is a label for the control line.  It is used as an internal
  state indicator and in ctlinnd messages to control the server.  If omitted,
  the line number is used.

  The second field specifies when this control line should be used.  It
  consists of a list of labels, and special indicators, separated by
  whitespace.  If the current state matches against any of the labels in this
  field, this line will be used as described below.  The values that may be
  used are:

  -    This line matches if the current state is the same as the label on
       this line, or if the current state is ``run,'' the initial state.
       This is also the default state if this field is empty.

  +    This line matches if the current state is ``run.''

  *    This line always matches.

  label
       This line matches if the current state is the specified ``label.''

  -label
       This line matches if the current state is not the specified ``label.''

  The third field specifies a shell command that is invoked if this line
  matches.  Do not use any shell filename expansion characters such as ``*'',
  ``?'', or ``['' (even quoted, they're not likely to work as intended).  If
  the command succeeds, as indicated by its exit status, it is expected to
  have printed a single integer to standard output.  This gives the value of
  this control line, to be used below.	If the command fails, the line is
  ignored.  The command is executed with its current directory set to the
  news spool directory, <patharticles in inn.conf>.

  The fourth field specifies the operator to use to test the value returned
  above.  It should be one of the two letter numeric test operators defined
  in test(1) such as ``eq'', ``lt'' and the like.  The leading dash (``-'')
  should not be included.

  The fifth field specifies a constant with which to compare the value using
  the operator just defined.  This is done by invoking the command:
       test value -operator constant
  The line is said to ``succeed'' if it returns true.

  The sixth field specifies what should be done if the line succeeds, and in
  some cases if it fails.  Any of the following words may be used:

  throttle
       Causes innwatch to throttle the server if this line succeeds.  It also
       sets the state to the value of the line's label.	 If the line fails,
       and the state was previously equal to the label on this line (that is,
       this line had previously succeeded), then a go command will be sent to
       the server, and innwatch will return to the ``run'' state.  The
       ``throttle'' is only performed if the current state is ``run'' or a
       state other than the label of this line, regardless of whether the
       command succeeds.

  pause
       Is identical to ``throttle'' except that the server is paused.

  shutdown
       Sends a ``shutdown'' command to the server.  It is for emergency use
       only.

  flush
       Sends a ``flush'' command to the server.

  go   Causes innwatch to send a ``go'' command to the server and to set the
       state to ``run.''

  exit Causes innwatch to exit.

  skip The result of the control file is skipped for the current pass.

  The last field specifies the reason that is used in those ctlinnd commands
  that require one.  More strictly, it is part of the reason - innwatch
  appends some information to it.  In order to enable other sites to
  recognize the state of the local innd server, this field should usually be
  set to one of several standard values.  Use ``No space'' if the server is
  rejecting articles because of a lack of filesystem resources.	 Use
  ``loadav'' if the server is rejecting articles because of a lack of CPU
  resources.

  Once innwatch has taken some action as a consequence of its control line,
  it skips the rest of the control file for this pass.	If the action was to
  restart the server (that is, issue a ``go'' command), then the next pass
  will commence almost immediately, so that innwatch can discover any other
  condition that may mean that the server should be suspended again.

EXAMPLES
       @@@inndf .@lt@10000@throttle@No space
       @@@inndf -i .@lt@1000@throttle@No space (inodes)

  The first line causes the server to be throttled if the free space drops
  below 10000 units (using whatever units inndf(8) uses), and restarted again
  when free space increases above the threshold.

  The second line does the same for inodes.

  The next three lines act as a group and should appear in the following
  order.  It is easier to explain them, however, if they are described from
  the last up.
       !load!load hiload!loadavg!lt!5!go!
       :hiload:+ load:loadavg:gt:8:throttle:loadav
       /load/+/loadavg/ge/6/pause/loadav
  The final line causes the server to be paused if innwatch is in the ``run''
  state and the load average rises to, or above, six.  The state is set to
  ``load'' when this happens.  The previous line causes the server to be
  throttled when innwatch is in the ``run'' or ``load'' state, and the load
  average rises above eight.  The state is set to ``hiload'' when this
  happens.  Note that innwatch can switch the server from ``paused'' to
  ``throttled'' if the load average rises from below six to between six and
  seven, and then to above eight.  The first line causes the server to be
  sent a ``go'' command if innwatch is in the ``load'' or ``hiload'' state,
  and the load average drops below five.

  Note that all three lines assume a mythical command loadavg that is assumed
  to print the current load average as an integer.  In more practical
  circumstances, a pipe of uptime into awk is more likely to be useful.

BUGS
  This file must be tailored for each individual site, the sample supplied is
  truly no more than a sample.	The file should be ordered so that the more
  common problems are tested first.

  The ``run'' state is not actually identified by the label with that three
  letter name, and using it will not work as expected.

  Using an ``unusual'' character for the delimiter such as ``('', ``*'',
  ``&'', ```'', ``''', and the like, is likely to lead to obscure and hard to
  locate bugs.

HISTORY
  Written by <kre@munnari.oz.au> for InterNetNews.  This is revision 1.7.4.1,
  dated 2000/08/17.

SEE ALSO
  inn.conf(5), innd(8), inndf(8), ctlinnd(8), news.daily(8).

Index for Section 5

Alphabetical listing for I

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