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check_remote_by_http
- nagios plugin for getting remote values by
http
check_remote_by_http
[ -D ] [ -L ] [ -A(0|1|2|3|4) ] -w warnlevel
-c critlevel -H ip-address -p port [ -t timeout ] [ -T(O|W|C) ] [ -u unit ] key
check_remote_by_http is a nagios plugin for remote checking
hosts by (simplified) http.
It was written as a (fast) alternative to net-snmp
and it is designed to work with knoerre, a small http-server.
check_remote_by_http
sends according to the given key a HTTP request to
the remote server. Then it expects a value as a result of the remote check.
It takes the value from the last line of the remote HTTP response. The value
will be interpreted as a positive integer with up to 63 bits.
If the remote value is greater than the specified warning or critical level
then check_remote_by_http
will also recognize the line before and print
it contents as additional data. This additional or debug information is
printed between the remote value and the performance data. Its output can
be formatted as HTML-data with the original URL sent to the remote host
as link. See examples.
key is a string sent as http
GET request to the remote server and depends
on the type of the remote http server. If i.e. the key load1 is specified
then the following request is sent:
GET /load1 HTTP/1.0
If you use i.e.
knoerre as remote http
server then you will get a http response with the
current load-per-1-minute as remote check value in the last line and the complete
output of /proc/loadavg in the line before.
- -w warnlevel
- Specify
the warning level. The remote value must be greater than the warnlevel to
trigger.
- -c critlevel
- Specify the critical level. The remote value must be
greater than the critlevel to trigger.
- -H ip-address
- Specify the IP address
of the remote server to check.
- -p port
- Specify the port of the http
server
on the remote host.
- -u unit
- Specify an optional unit string which is placed
after the remote value and which is visible in nagios.
- -t timeout
- The plugins
internal timeout in seconds (default: 10).
- -TO
- On timeout return OK instead
of UNKNOWN.
- -TW
- On timeout return WARNING instead of UNKNOWN.
- -TC
- On timeout
return CRITICAL instead of UNKNOWN.
- -L
- Show additional data as link.
- -A(0|1|2|3|4)
- Specify the level of the remote value which must be reached to print the
additional data. "-A0" causes printing if state is "OK" and "-A4" will disable
printing. "-A1" is currently the default setting.
- -D
- Use TCP_DEFER_ACCEPT
(see tcp(7)
). This can speed up our http-communication
by approx. 10 percent,
but it breaks tcp-communication by RFC - like many others too. It can also
cause trouble with loadbalancers like F5 which send "early" ACK packets
to the server before ACK from client.
According to the Nagios
Plugin API the Return Code is 0 for state "OK", 1 for "WARNING", 2 for
"CRITICAL" and 3 for "UNKNOWN".
check_remote_by_http
does not use
any files, a sample nagios config is shown here:
# cat /etc/nagios/msc.cfg
define service{
use service-1min
name load1
check_command check_remote_generic!8!20!load1
register 0
}
# cat /etc/nagios/remote-generic.cfg
define command{
command_name check_remote_generic
command_line $USER1$/check_remote_by_http
-w $ARG1$ -c $ARG2$ -H $HOSTADDRESS$
-p 8888 $ARG3$
}
check_remote_by_http(1)
, knoerre(1)
http://downloads.tuxad.de/nagios-fwb
Some examples of check_remote_by_http
with knoerre as remote http server:
$ check_remote_by_http
-w 100000 -c
180000 -H 192.168.1.1 -u " direntries" -p 8888 maxdirentries/2/home/www/@/html/typo3temp
REMOTE OK - 15621 direntries | maxdirentries/2/home/www/@/html/typo3temp=15621direntries;100000;180000
$ check_remote_by_http
-w 25 -c 35 -H 192.168.1.1 -p 8888 dirlevels/home/www/@/html
REMOTE OK - 14 | dirlevels/home/www/@/html=14;25;35
$ check_remote_by_http
-w 5000 -c 8000 -H 192.168.1.1 -u " KB" -p 8888 filesizesbysuffix/.gif/2/home/www/@/html/typo3temp
REMOTE OK - 262 KB | filesizesbysuffix/.gif/2/home/www/@/html/typo3temp=262KB;5000;8000
$ check_remote_by_http
-w 5000 -c 8000 -H 192.168.1.1 -u " KB" -p 8888 filesizesbysuffix/.jpg/2/home/www/@/html/typo3temp
REMOTE OK - 1826 KB | filesizesbysuffix/.jpg/2/home/www/@/html/typo3temp=1826KB;5000;8000
$ check_remote_by_http
-w 600000 -c 1800000 -H 192.168.1.1 -u " KB" -p 8888 filesizes/home/www/@/logs/access.log
REMOTE OK - 19081 KB | filesizes/home/www/@/logs/access.log=19081KB;600000;1800000
$ check_remote_by_http
-L -w 400 -c 1200 -H 192.168.1.1 -p 8888 -u " MB used" swap
REMOTE WARNING - 1108 MB used (<a href="http://192.168.1.1:8888/swap
" >memtotal:2000
swaptotal:1999</a>) | swap=1108MB;400;1200
Frank Bergmann, http://www.tuxad.com
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