Provided by: inn_1.7.2q-39_i386 bug

NAME

       innwatch.ctl - control Usenet supervision by innwatch

DESCRIPTION

       The  file  /etc/news/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, /var/spool/news.

       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

              @@@df .|awk ’NR==2 {print $4}’@lt@10000@throttle@No space
              @@@df -i .|awk ’NR==2 {print $4}’@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 df 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 1.5,
       dated 1996/09/06.

SEE ALSO

       innd(8), ctlinnd(8), news.daily(8).

                                                               INNWATCH.CTL(5)