Provided by: inn2_2.5.2+20110413-1_i386 bug

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, for example:

              :label:state:condition:test:limit:command:reason
       or
              @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 this control line.  It is used as an
       internal state indicator and in ctlinnd messages to control the server.
       If this field is empty, 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   articles   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  remainder  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
       5909, dated 2002-12-03.

SEE ALSO

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

                                                               INNWATCH.CTL(5)