NAME¶
mrtg-reference - MRTG 2.17.4 configuration reference
OVERVIEW¶
The runtime behaviour of MRTG is governed by a configuration file.
Run-of-the-mill configuration files can be generated with
cfgmaker.
(Check cfgmaker). But for more elaborate configurations some hand-tuning is
required.
This document describes all the configuration options understood by the mrtg
software.
SYNTAX¶
MRTG configuration file syntax follows some simple rules:
- •
- Keywords must start at the beginning of a line.
- •
- Lines which follow a keyword line which start with a blank
are appended to the keyword line
- •
- Empty Lines are ignored
- •
- Lines starting with a # sign are comments.
- •
- You can add other files into the configuration file using
Include: file
Example:
Include: base-options.inc
If included files are specified with relative paths, both the current
working directory and the directory containing the main config file will
be searched for the files. The current working directory will be searched
first.
If the included filename contains an asterisk, then this is taken as a
wildcard for zero or more characters, and all matching files are included.
Thus, you can use this statement to include all files in a specified
subdirectory.
Example:
Include: servers/*.cfg
In this case, you should be very careful that your wildcard pattern does not
find a match relative to the current working directory if you mean it to
be relative to the main config file directory, since the working directory
is checked for a match first (as with a normal Include directive).
Therefore, use of something like '*/*' is discouraged.
GLOBAL KEYWORDS¶
WorkDir¶
WorkDir specifies where the logfiles and the webpages should be created.
Example:
WorkDir: /usr/tardis/pub/www/stats/mrtg
OPTIONAL GLOBAL KEYWORDS¶
HtmlDir¶
HtmlDir specifies the directory where the html (or shtml, but we'll get on to
those later) lives.
NOTE: Workdir overrides the settings for htmldir, imagedir and logdir.
Example:
Htmldir: /www/mrtg/
ImageDir¶
ImageDir specifies the directory where the images live. They should be under the
html directory.
Example:
Imagedir: /www/mrtg/images
LogDir¶
LogDir specifies the directory where the logs are stored. This need not be under
htmldir directive.
Example:
Logdir: /www/mrtg/logs
Forks (UNIX only)¶
With system that supports fork (UNIX for example), mrtg can fork itself into
multiple instances while it is acquiring data via snmp.
For situations with high latency or a great number of devices this will speed
things up considerably. It will not make things faster, though, if you query a
single switch sitting next door.
As far as I know NT can not fork so this option is not available on NT.
Example:
Forks: 4
EnableIPv6¶
When set to yes, IPv6 support is enabled if the required libraries are present
(see the mrtg-ipv6 manpage). When IPv6 is enabled, mrtg can talk to routers
using SNMP over IPv6 and targets may be specified by their numeric IPv6
addresses as well as by hostname or IPv4 address.
If IPv6 is enabled and the target is a hostname, mrtg will try to resolve the
hostname to an IPv6 address and, if this fails, to an IPv4 address. Note that
mrtg will only use IPv4 if you specify an IPv4 address or a hostname with no
corresponding IPv6 address; it will not fall back to IPv4 if it simply fails
to communicate with the target using IPv6. This is by design.
Note that many routers do not currently support SNMP over IPv6. Use the
IPv4Only per target option for these routers.
IPv6 is disabled by default.
Example:
EnableIPv6: Yes
EnableSnmpV3¶
When set to yes, uses the Net::SNMP module instead of the SNMP_SESSION module
for generating snmp queries. This allows the use of SNMPv3 if other snmpv3
parameters are set.
SNMPv3 is disabled by default.
Example:
EnableSnmpV3: yes
Refresh¶
How many seconds apart should the browser (Netscape) be instructed to reload the
page? If this is not defined, the default is 300 seconds (5 minutes).
Example:
Refresh: 600
Interval¶
How often do you call mrtg? The default is 5 minutes. If you call it less often,
you should specify it here. This does two things:
- •
- The generated HTML page contains the right information
about the calling interval ...
- •
- A META header in the generated HTML page will instruct
caches about the time-to-live of this page .....
In this example, we tell mrtg that we will be calling it every 10 minutes. If
you are calling mrtg every 5 minutes, you can leave this line commented out.
Example:
Interval: 10
Note that unless you are using rrdtool you can not set Interval to less than 5
minutes. If you are using rrdtool you can set interval in the format
Interval: MM[:SS]
Down to 1 second. Note though, setting the Interval for an rrdtool/mrtg setup
will influence the initial creation of the database. If you change the
interval later, all existing databases will remain at the resolution they were
initially created with. Also note that you must make sure that your mrtg-rrd
Web-frontend can deal with this kind of Interval setting.
MaxAge¶
MRTG relies heavily on the real time clock of your computer. If the time is set
to a wrong value, especially if it is advanced far into the future, this will
cause mrtg to expire lots of supposedly old data from the log files.
To prevent this, you can add a 'reasonability' check by specifying a maximum age
for log files. If a file seems to be older, mrtg will not touch it but
complain instead, giving you a chance to investigate the cause.
Example:
MaxAge: 7200
The example above will make mrtg refuse to update log files older than 2 hours
(7200 seconds).
WriteExpires¶
With this switch mrtg will generate .meta files for CERN and Apache servers
which contain Expiration tags for the html and gif files. The *.meta files
will be created in the same directory as the other files, so you will have to
set "MetaDir ." and "MetaFiles on" in your apache.conf or
.htaccess file for this to work
NOTE: If you are running Apache-1.2 or later, you can use the mod_expire to
achieve the same effect ... see the file htaccess.txt
Example:
WriteExpires: Yes
NoMib2¶
Normally we ask the SNMP device for 'sysUptime' and 'sysName' properties. Some
do not have these. If you want to avoid getting complaints from mrtg about
these missing properties, specify the nomib2 option.
An example of agents which do not implement base mib2 attributes are Computer
Associates - Unicenter TNG Agents. CA relies on using the base OS SNMP agent
in addition to its own agents to supplement the management of a system.
Example:
NoMib2: Yes
SingleRequest¶
Some SNMP implementations can not deal with requests asking for multiple snmp
variables in one go. Set this in your cfg file to force mrtg to only ask for
one variable per request.
Examples
SingleRequest: Yes
SnmpOptions¶
Apart from the per target timeout options, you can also configure the behaviour
of the snmpget process on a more profound level. SnmpOptions accepts a hash of
options. The following options are currently supported:
timeout => $default_timeout,
retries => $default_retries,
backoff => $default_backoff,
default_max_repetitions => $max_repetitions,
use_16bit_request_ids => 1,
lenient_source_port_matching => 0,
lenient_source_address_matching => 1
The values behind the options indicate the current default value. Note that
these settings OVERRIDE the per target timeout settings.
A per-target SnmpOptions[] keyword will override the global settings. That
keyword is primarily for SNMPv3.
The 16bit request ids are the only way to query the broken SNMP implementation
of SMC Barricade routers.
Example:
SnmpOptions: retries => 2, only_ip_address_matching => 0
Note that AS/400 snmp seems to be broken in a way which prevents mrtg from
working with it unless
SnmpOptions: lenient_source_port_matching => 1
is set.
IconDir¶
If you want to keep the mrtg icons in someplace other than the working (or
imagedir) directory, use the
IconDir variable for defining the url of
the icons directory.
Example:
IconDir: /mrtgicons/
LoadMIBs¶
Load the MIB file(s) specified and make its OIDs available as symbolic names.
For better efficiancy, a cache of MIBs is maintained in the WorkDir.
Example:
LoadMIBs: /dept/net/mibs/netapp.mib,/usr/local/lib/ft100m.mib
Language¶
Switch output format to the selected Language (Check the
translate
directory to see which languages are supported at the moment. In this
directory you can also find instructions on how to create new translations).
Currently the following laguages are supported:
big5 brazilian bulgarian catalan chinese croatian czech danish dutch eucjp
french galician gb gb2312 german greek hungarian icelandic indonesia iso2022jp
italian korean lithuanian malay norwegian polish portuguese romanian russian
russian1251 serbian slovak slovenian spanish swedish turkish ukrainian
Example:
Language: danish
Setting LogFormat to 'rrdtool' in your mrtg.cfg file enables rrdtool mode. In
rrdtool mode, mrtg relies on
rrdtool to do its logging. See mrtg-rrd.
Example:
LogFormat: rrdtool
LibAdd¶
If you are using rrdtool mode and your
rrdtool Perl module (RRDs.pm) is
not installed in a location where perl can find it on its own, you can use
LibAdd to supply an appropriate path.
Example:
LibAdd: /usr/local/rrdtool/lib/perl/
PathAdd¶
If the
rrdtool executable can not be found in the normal
"PATH", you can use this keyword to add a suitable directory to your
path.
Example:
PathAdd: /usr/local/rrdtool/bin/
RRDCached¶
If you are running RRDTool 1.4 or later with
rrdcached, then you can
configure MRTG to take advantage of this for updates, either by using the
RRDCACHED_ADDRESS environment variable, or by setting the RRDCached keyword in
the configuration file. Note that, if both are set, the configuration file
keyword will take precedence.
Only UNIX domain sockets are fully supported prior to RRDTool v1.5, and you
should note that using RRDCached mode will disable all Threshold checking
normally done by MRTG. Appropriate warning messages will be printed if
necessary.
Examples:
RRDCached: unix:/var/tmp/rrdcached.sock
RRDCached: localhost:42217
RunAsDaemon¶
The RunAsDaemon keyword enables daemon mode operation. The purpose of daemon
mode is that MRTG is launched once and not repeatedly (as it is with cron).
This behavior saves computing resourses as loading and parsing of
configuration files happens only once on startup, and if the configuration
file is modified.
Using daemon mode MRTG itself is responible for timing the measurement
intervals. Therfore its important to set the Interval keyword to an apropiate
value.
Note that when using daemon mode MRTG should no longer be started from cron as
each new process runs forever. Instead MRTG should be started from the command
prompt or by a system startup script.
If you want mrtg to run under a particular user and group (it is not recomended
to run MRTG as root) then you can use the
--user=user_name and
--group=group_name options on the mrtg commandline.
mrtg --user=mrtg_user --group=mrtg_group mrtg.cfg
Also note that in daemon mode restarting the process is required in order to
activate changes in the config file.
Under UNIX, the Daemon switch causes mrtg to fork into background after checking
its config file. On Windows NT the MRTG process will detach from the console,
but because the NT/2000 shell waits for its children you have to use this
special start sequence when you launch the program:
start /b perl mrtg mrtg.cfg
You may have to add path information equal to what you add when you run mrtg
from the commandline.
Example
RunAsDaemon: Yes
Interval: 5
This makes MRTG run as a daemon beginning data collection every 5 minutes
If you are daemontools and still want to run mrtg as a daemon you can
additionally specify
NoDetach: Yes
this will make mrtg run but without detaching it from the terminal.
If the modification date on the configuration file changes during operation,
then MRTG will re-read the configuration on the next polling cycle. Note that
sub-files which are included from the main configuration do not have their
modification times monitored, only the top-level file is so checked.
ConversionCode¶
Some devices may produce non-numeric values that would nevertheless be useful to
graph with MRTG if those values could be converted to numbers. The
ConversionCode keyword specifies the path to a file containing Perl code to
perform such conversions. The code in this file must consist of one or more
Perl subroutines. Each subroutine must accept a single string argument and
return a single numeric value. When RRDtool is in use, a decimal value may be
returned. When the name of one of these subroutines is specified in a target
definition (see below), MRTG calls it twice for that target, once to convert
the the input value being monitored and a second time to convert the output
value. The subroutine must return an undefined value if the conversion fails.
In case of failure, a warning may be posted to the MRTG log file using Perl's
warn function. MRTG imports the subroutines into a separate name space
(package MRTGConversion), so the user need not worry about pollution of MRTG's
global name space. MRTG automatically prepends this package declaration to the
user-supplied code.
Example: Suppose a particular OID returns a character string whose length is
proportional to the value to be monitored. To convert this string to a number
that can be graphed by MRTG, create a file arbitrarily named
"MyConversions.pl" containing the following code:
# Return the length of the string argument
sub Length2Int {
my $value = shift;
return length( $value );
}
Then include the following global keyword in the MRTG configuration file
(assuming that the conversion code file is saved in the mrtg/bin directory
along with mrtg itself):
ConversionCode: MyConversions.pl
This will cause MRTG to include the definition of the subroutine Length2Int in
its execution environment. Length2Int can then be invoked on any target by
appending "|Length2Int" to the target definition as follows:
Target[myrouter]: 1.3.6.1.4.1.999.1&1.3.6.1.4.1.999.1:public@mydevice|Length2Int
See "Extended Host Name Syntax" below for complete target definition
syntax information.
PER TARGET CONFIGURATION¶
Each monitoring target must be identified by a unique name. This name must be
appended to each parameter belonging to the same target. The name will also be
used for naming the generated webpages, logfiles and images for this target.
Target¶
With the
Target keyword you tell mrtg what it should monitor. The
Target keyword takes arguments in a wide range of formats:
- Basic
- The most basic format is "port:community@router"
This will generate a traffic graph for the interface 'port' of the host
'router' (dns name or IP address) and it will use the community
'community' (snmp password) for the snmp query.
Example:
Target[myrouter]: 2:public@wellfleet-fddi.domain
If your community contains a "@" or a " " these
characters must be escaped with a "\".
Target[bla]: 2:stu\ pi\@d@router
- SNMPv2c
- If you have a fast router you might want to try to poll the
ifHC* counters. This feature gets activated by switching to SNMPv2c.
Unfortunately not all devices support SNMPv2c yet. If it works, this will
prevent your counters from wraping within the 5 minute polling interval,
since we now use 64 bit instead of the normal 32 bit.
Example:
Target[myrouter]: 2:public@router1:::::2
- SNMPv3
- As an alternative to SNMPv2c, SNMPv3 provides access to the
ifHC* counters, along with encryption. Not all devices support SNMPv3, and
you will also need the perl Net::SNMP library in order to use it. It is
recommended that cfgmaker be used to generate configurations involving
SNMPv3, as it will check if the Net::SNMP library is loadable, and will
switch to SNMPv2c if v3 is unavailable.
SNMP v3 requires additional authentication parameters, passed using the
SnmpOptions[] per-target keyword.
Example:
Target[myrouter]: 2:router1:::::3
SnmpOptions[myrouter]: username=>'user1'
- noHC
- Not all routers that support SNMPv2 or SNMPv3 provide the
ifHC* counters on every interface. The noHC[] per-target keyword signals
that the low-speed counters ifInOctets and ifOutOctets should be queried
instead. cfgmaker will automatically insert this tag if SNMPv2 or SNMPv3
is specified but the ifHC* counters are unavailable.
Example:
Target[myrouter]: #Bri0:router1:::::3
SnmpOptions[myrouter]: username=>'user1'
noHC[myrouter]: yes
- Reversing
- Sometimes you are sitting on the wrong side of the link,
and you would like to have mrtg report Incoming traffic as Outgoing and
vice versa. This can be achieved by adding the '-' sign in front of the
"Target" description. It flips the incoming and outgoing traffic
rates.
Example:
Target[ezci]: -1:public@ezci-ether.domain
- Explicit OIDs
- You can also explicitly define which OID to query by using
the following syntax 'OID_1&OID_2:community@router' The following
example will retrieve error counts for input and output on interface 1.
MRTG needs to graph two variables, so you need to specify two OID's such
as temperature and humidity or error input and error output.
Example:
Target[myrouter]: 1.3.6.1.2.1.2.2.1.14.1&1.3.6.1.2.1.2.2.1.20.1:public@myrouter
- MIB Variables
- MRTG knows a number of symbolic SNMP variable names. See
the file mibhelp.txt for a list of known names. One example are the
ifInErrors and ifOutErrors. This means you can specify the above as:
Example:
Target[myrouter]: ifInErrors.1&ifOutErrors.1:public@myrouter
- SnmpWalk
- It may be that you want to monitor an snmp object that is
only reachable by 'walking'. You can get mrtg to walk by prepending the
OID with the string WaLK or if you want a particular entry from the
table returned by the walk you can use WaLKx where x
is a number starting from 0 (!).
Example:
Target[myrouter]: WaLKstrangeOid.1&WaLKstrangeOid.2:public@myrouter
Target[myrouter]: WaLK3strangeOid.1&WaLK4strangeOid.2:public@myrouter
- SnmpGetNext
- A special case of an snmp object that is only reachable by
'walking' occurs when a single snmpgetnext will return the correct value,
but snmpwalk fails. This may occur with snmp V2 or V3, as the snmpgetbulk
method is used in these versions. You can get mrtg to use getnext instead
of getbulk by prepending the OID with the string GeTNEXT.
Example:
Target[myrouter]: GeTNEXTstrangeOid&GeTNEXTstrangeOid:public@myrouter
- Counted SNMP Walk
- In other situations, an snmpwalk is needed to count rows,
but the actual data is uninteresting. For example, counting the number of
mac-addresses in a CAM table, or the number of simultaneous dialup
sessions. You can get MRTG to count the number of instances by prepending
the OID with the string CnTWaLK. The following will retrieve the
number of simultaneous VOIP calls on some routers:
Example:
Target[myrouter]: CnTWaLK1.3.6.1.4.1.9.10.55.1.1.1.1.3&CnTWaLK1.3.6.1.4.1.9.10.55.1.1.1.1.3:public@myrouter
- Interface by IP
- Sometimes SNMP interface index can change, like when new
interfaces are added or removed. This can cause all Target entries in your
config file to become offset, causing MRTG to graphs wrong instances etc.
MRTG supports IP address instead of ifindex in target definition. Then
MRTG will query snmp device and try to map IP address to the current
ifindex. You can use IP addresses in every type of target definition by
adding IP address of the numbered interface after OID and separation char
'/'.
Make sure that the given IP address is used on your same target router,
especially when graphing two different OIDs and/or interface split by
'&' delimiter.
You can tell cfgmaker to generate such references with the option
--ifref=ip.
Example:
Target[myrouter]: /1.2.3.4:public@wellfleet-fddi.domain
Target[ezci]: -/1.2.3.4:public@ezci-ether.domain
Target[myrouter]: ifInErrors/1.2.3.4&ifOutErrors/1.2.3.4:public@myrouter
- Interface by Description
- If you can not use IP addresses you might want to use the
interface names. This works similar to the IP address aproach except that
the prefix to use is a \ instead of a /
You can tell cfgmaker to generate such references with the option
--ifref=descr.
Example:
Target[myrouter]: \My-Interface2:public@wellfleet-fddi.domain
Target[ezci]: -\My-Interface2:public@ezci-ether.domain
Target[myrouter]: ifInErrors\My-If2&ifOutErrors\My-If3:public@myrouter
If your description contains a "&", a ":", a
"@" or a " " you can include them but you must escape
with a backlash:
Target[myrouter]: \fun\:\ ney\&ddd:public@hello.router
- Interface by Name
- This is the only sensible way to reference the interfaces
of your switches.
You can tell cfgmaker to generate such references with the option
--ifref=name.
Example:
Target[myrouter]: #2/11:public@wellfleet-fddi.domain
Target[ezci]: -#2/11:public@ezci-ether.domain
Target[myrouter]: ifInErrors#3/7&ifOutErrors#3/7:public@myrouter
If your description contains a "&", a ":", a
"@" or a " " you can include them but you must escape
with a backlash:
Target[myrouter]: #\:\ fun:public@hello.router
Note that the # sign will be interpreted as a comment character if it is the
first non white-space character on the line.
- Interface by Ethernet Address
- When the SNMP interface index changes, you can key that
interface by its 'Physical Address', sometimes called a 'hard address',
which is the SNMP variable 'ifPhysAddress'. Internally, MRTG matches the
Physical Address from the *.cfg file to its current index, and then uses
that index for the rest of the session.
You can use the Physical Address in every type of target definition by
adding the Physical Address after the OID and the separation char '!'
(analogous to the IP address option). The Physical address is specified as
'-' delimited octets, such as "0a-0-f1-5-23-18" (omit the double
quotes). Note that some routers use the same Hardware Ethernet Address for
all of their Interfaces which prevents unique interface identification.
Mrtg will notice such problems and alert you.
You can tell cfgmaker to generate configuration files with hardware ethernet
address references by using the option --ifref=eth.
Example:
Target[myrouter]: !0a-0b-0c-0d:public@wellfleet-fddi.domain
Target[ezci]: -!0-f-bb-05-71-22:public@ezci-ether.domain
Target[myrouter]: 1.3.6.1.2.1.2.2.1.14!0a-00-10-23-44-51& *BREAK*
1.3.6.1.2.1.2.2.1.14!0a-00-10-23-44-51:public@myrouter
Target[myrouter]: ifInErrors!0a-00-10-23-44-51& *BREAK*
ifOutErrors!0a-00-10-23-44-51:public@myrouter
Join the lines at *BREAK* ...
- Interface by Type
- It seems that there are devices that try to defy all
monitoring efforts: the interesting interfaces have neither ifName nor a
constant ifDescr not to mention a persistent ifIndex. The only way to get
a constant mapping is by looking at the interface type, because the
interface you are interested in is unique in the device you are looking at
...
You can tell cfgmaker to generate such references with the option
--ifref=type.
Example:
Target[myrouter]: %13:public@wellfleet-fddi.domain
Target[ezci]: -%13:public@ezci-ether.domain
Target[myrouter]: ifInErrors%13&ifOutErrors%14:public@myrouter
- Extended positioning of ifIndex
- There are OIDs that contain the interface index at some
inner position within the OID. To use the above mentioned Interface by
IP/Description/Name/Type methods in the target definition the keyword
'IndexPOS' can be used to indicate the position of ifIndex. If 'IndexPOS'
is not used the ifIndex will be appended at the end of the OID.
Example:
Target[myrouter]: OID.IndexPOS.1/1.2.3.4&OID.IndexPOS.1/1.2.3.4:public@myrouter
Replace OID by your numeric OID.
- Extended Host Name Syntax
- In all places where ``community@router'' is accepted, you
can add additional parameters for the SNMP communication using
colon-separated suffixes. You can also append a pipe symbol ( | ) and the
name of a numeric conversion subroutine as described under the global
keyword "ConversionCode" above. The full syntax is as follows:
community@router[:[port][:[timeout][:[retries][:[backoff][:[version]][|name]]]]]
where the meaning of each parameter is as follows:
- port
- the UDP port under which to contact the SNMP agent
(default: 161)
The complete syntax of the port parameter is
remote_port[!local_address[!local_port]]
Some machines have additional security features that only allow SNMP queries
to come from certain IP addresses. If the host doing the query has
multiple interface, it may be necessary to specify the interface the query
should come from.
The port parameter allows the specification of the port of the machine being
queried. In addition, the IP address (or hostname) and port of the machine
doing the query may be specified.
Examples:
somehost
somehost:161
somehost:161!192.168.2.4!4000 use 192.168.2.4 and port 4000 as source
somehost:!192.168.2.4 use 192.168.2.4 as source
somehost:!!4000 use port 4000 as source
- timeout
- initial timeout for SNMP queries, in seconds (default:
2.0)
- retries
- number of times a timed-out request will be retried
(default: 5)
- backoff
- factor by which the timeout is multiplied on every retry
(default: 1.0).
- version
- for SNMP version. If you have a fast router you might want
to put a '2' here. For authenticated or encrypted SNMP, you can try to put
a '3' here. This will make mrtg try to poll the 64 bit counters and thus
prevent excessive counter wrapping. Not all routers support this though.
SNMP v3 requires additional setup, see SnmpOptions[] for full details.
Example:
3:public@router1:::::2
- name
- the name of the subroutine that MRTG will call to convert
the input and output values to integers. See the complete example under
the global keyword "ConversionCode" above.
Example:
1.3.6.1.4.1.999.1&1.3.6.1.4.1.999.2:public@mydevice:161::::2|Length2Int
This would retrieve values from the OID 1.3.6.1.4.1.999.1 for input and .2
for output on mydevice using UDP port 161 and SNMP version 2, and would
execute the user-defined numeric conversion subroutine Length2Int to
convert those values to integers.
A value that equals the default value can be omitted. Trailing colons can be
omitted, too. The pipe symbol followed by the name parameter, if present, must
come at the end. There must be no spaces around the colons or pipe symbol.
Example:
Target[ezci]: 1:public@ezci-ether.domain:9161::4
This would refer to the input/output octet counters for the interface with
ifIndex 1 on
ezci-ether.domain, as known by the SNMP agent
listening on UDP port 9161. The standard initial timeout (2.0 seconds) is
used, but the number of retries is set to four. The backoff value is the
default.
- Numeric IPv6 addresses
- If IPv6 is enabled you may also specify a target using its
IPv6 address. To avoid ambiguity with the port number, numeric IPv6
addresses must be placed in square brackets.
Example:
Target[IPv6test]: 2:public@[2001:760:4::]:6161::4
- External Monitoring Scripts
- If you want to monitor something which does not provide
data via snmp you can use some external program to do the data gathering.
The external command must return 4 lines of output:
- Line 1
- current state of the first variable, normally 'incoming
bytes count'
- Line 2
- current state of the second variable, normally 'outgoing
bytes count'
- Line 3
- string (in any human readable format), telling the uptime
of the target.
- Line 4
- string, telling the name of the target.
Depending on the type of data your script returns you might want to use the
'gauge' or 'absolute' arguments for the
Options keyword.
Example:
Target[myrouter]: `/usr/local/bin/df2mrtg /dev/dsk/c0t2d0s0`
Note the use of the backticks (`), not apostrophes (') around the command.
If you want to use a backtick in the command name this can be done but you must
escape it with a backslash ...
If your script does not have any data to return but does not want mrtg to
complain about invalid data, it can return 'UNKNOWN' instead of a number. Note
though that only rrdtool is realy equipped to handle unknown data well.
- Multi Target Syntax
- You can also combine several target definitions in a
mathematical expression. Any syntactically correct expression that the
Perl interpreter can evaluate to will work. An expression could be used,
for example, to aggregate both B channels in an ISDN connection or to
calculate the percentage hard disk utilization of a server from the
absolute used space and total capacity.
Examples:
Target[myrouter]: 2:public@wellfleetA + 1:public@wellfleetA
Target[myrouter]: .1.3.6.1.4.1.999.1&.1.3.6.1.4.1.999.2:public@mydevice /
.1.3.6.1.4.1.999.3&.1.3.6.1.4.1.999.4:public@mydevice * 100
Note that whitespace must surround each target definition in the expression.
Target definitions themselves must not contain whitespace, except in
interface descriptions and interface names, where each whitespace
character is escaped by a backslash.
MRTG automatically rounds the result of the expression to an integer unless
RRDTool logging is in use and the gauge option is in effect for the
target. Internally MRTG uses Perl's Math::BigFloat package to calculate
the result of the expression with 40 digits of precision. Even in extreme
cases, where, for example, you take the difference of two 64-bit integers,
the result of the expression should be accurate.
- SNMP Request Optimization
- MRTG is designed to economize on its SNMP requests. Where a
target definition appears more than once in the configuration file, MRTG
requests the data from the device only once per round of data collection
and uses the collected data for each instance of a particular target.
Recognition of two target definitions as being identical is based on a
simple string match rather than any kind of deeper semantic analysis.
Example:
Target[Targ1]: 1:public@CiscoA
Target[Targ2]: 2:public@CiscoA
Target[Targ3]: 1:public@CiscoA + 2:public@CiscoA
Target[Targ4]: 1:public@CISCOA
This results in a total of three SNMP requests. Data for 1:public@CiscoA and
2:public@CiscoA are requested only once each, and used for Targ1, Targ2,
and Targ3. Targ4 causes another SNMP request for 1:public@CISCOA, which is
not recognized as being identical to 1:public@CiscoA.
MaxBytes¶
The maximum value either of the two variables monitored are allowed to reach.
For monitoring router traffic this is normally the bytes per second this
interface port can carry.
If a number higher than
MaxBytes is returned, it is ignored. Also read
the section on
AbsMax for further info. The
MaxBytes value is
also used in calculating the Y range for unscaled graphs (see the section on
Unscaled).
Since most links are rated in bits per second, you need to divide their maximum
bandwidth (in bits) by eight (8) in order to get bytes per second. This is
very important to make your unscaled graphs display realistic information. T1
= 193000, 56K = 7000, 10 MB Ethernet = 1250000, 100 MB Ethernet = 12500000.
The
MaxBytes value will be used by mrtg to decide whether it got a
valid response from the router.
If you need two different MaxBytes values for the two monitored variables, you
can use MaxBytes1 and MaxBytes2 instead of MaxBytes.
Example:
MaxBytes[myrouter]: 1250000
Title¶
Title for the HTML page which gets generated for the graph.
Example:
Title[myrouter]: Traffic Analysis for Our Nice Company
OPTIONAL PER TARGET KEYWORDS¶
PageTop¶
Things to add to the top of the generated HTML page. Note that you can have
several lines of text as long as the first column is empty.
Note that the continuation lines will all end up on the same line in the html
page. If you want linebreaks in the generated html use the '\n' sequence.
Example:
PageTop[myrouter]: <H1>Traffic Analysis for ETZ C95.1</H1>
Our Campus Backbone runs over an FDDI line\n
with a maximum transfer rate of 12.5 megabytes per
Second.
RouterUptime¶
In cases where you calculate the used bandwidth from several interfaces you
normally don't get the router uptime and router name displayed on the web
page.
If these interfaces are on the same router and the uptime and name should be
displayed you have to specify its community and address again with the
RouterUptime keyword.
If you want to use a special OID for querying the router uptime, use prepend the
oid.
Example:
Target[kacisco.comp.edu]: 1:public@194.64.66.250 + 2:public@194.64.66.250
RouterUptime[kacisco.comp.edu]: public@194.64.66.250
RouterUptime[kacisco.comp.edu]: hrSystemUptime.0:public@194.64.66.250
RouterName¶
If the default name of the router is incorrect/uninformative, you can use
RouterName to specify a different OID on either the same or a different host.
A practical example: sysName on BayTech DS72 units always display
"ds72", no matter what you set the Unit ID to be. Instead, the Unit
ID is stored at 1.3.6.1.4.1.4779.1.1.3.0, so we can have MRTG display this
instead of sysName.
Example:
RouterName[kacisco.comp.edu]: 1.3.6.1.4.1.4779.1.1.3.0
A different OID on a different host can also be specified:
RouterName[kacisco.comp.edu]: 1.3.6.1.4.1.4779.1.1.3.0:public@194.64.66.251
MaxBytes1¶
Same as MaxBytes, for variable 1.
MaxBytes2¶
Same as MaxBytes, for variable 2.
IPv4Only¶
Many IPv6 routers do not currently support SNMP over IPv6 and must be monitored
using IPv4. The IPv4Only option forces mrtg to use IPv4 when communicating
with the target, even if IPv6 is enabled. This is useful if the target is a
hostname with both IPv4 and IPv6 addresses; without the IPv4Only keyword,
monitoring such a router will not work if IPv6 is enabled.
If set to no (the default), mrtg will use IPv6 unless the target has no IPv6
addresses, in which case it will use IPv4. If set to yes, mrtg will only use
IPv4.
Note that if this option is set to yes and the target does not have an IPv4
address, communication with the target will fail.
This option has no effect if IPv6 is not enabled.
Example:
Target[v4onlyrouter_1]: 1:public@v4onlyrouter
IPv4Only[v4onlyrouter_1]: Yes
SnmpOptions (V3)¶
SNMPv3 requires a fairly rich set of options. This per-target keyword allows
access to the User Security Model of SNMPv3. Options are listed in the same
syntax as a perl hash.
Security Modes
SNMPv3 has three security modes, defined on the device being polled. For
example, on Cisco routers the security mode is defined by the snmp-server
group global configuration command.
- NoAuthNoPriv
- Neither Authentication nor Privacy is defined. Only the
Username option is specified for this mode.
Example:
SnmpOptions[myrouter]: username=>'user1'
- AuthNoPriv
- Uses a Username and a password. The password can be hashed
using the snmpkey application, or passed in plain text along with the
ContextEngineID
Example:
SnmpOptions[myrouter]: username=>'user1',authpassword=>'example',
contextengineid=>'80000001110000004000000'
- Priv
- Both Authentication and Privacy is defined. The default
privacy protocol is des.
Example:
SnmpOptions[myrouter]:
authkey=>'0x1e93ab5a396e2af234c8920e61cfe2028072c0e2',
authprotocol=>'sha',privprotocol=>'des',username=>'user1',
privkey=>'0x498d74940c5872ed387201d74b9b25e2'
snmp options
The following option keywords are recognized:
- username
- The user associated with the User Security Model
- contextname
- An SNMP agent can define multiple contexts. This keyword
allows them to be polled.
- contextengineid
- A unique 24-byte string identifying the snmp-agent.
- authpassword
- The plaintext password for a user in either AuthNoPriv or
Priv mode.
- authkey
- A md5 or sha hash of the plain-text password, along with
the engineid. Use the snmpkey commandline program to generate this hash,
or use Net::SNMP::Security::USM in a script.
- authprotocol {sha|md5}
- The hashing algorithm defined on the SNMP client. Defaults
to md5.
- privpassword
- A plaintext pre-shared key for encrypting snmp packets in
Priv mode.
- privkey
- A hash of the plain-text pre-shared key, along with the
engineid. Use the snmpkey commandline program to generate this hash, or
use Net::SNMP::Security::USM in a script.
- privprotocol
{des|3desede|aescfb128|aescfb192|aescfb256}
- Specifies the encryption method defined on the snmp agent.
The default is des.
Things to add to the bottom of the generated HTML page. Note that you can have
several lines of text as long as the first column is empty.
Note that the continuation lines will all end up on the same line in the html
page. If you want linebreaks in the generated html use the '\n' sequence.
The material will be added just before the </BODY> tag:
Example:
PageFoot[myrouter]: Contact <A HREF="mailto:peter@x.yz">Peter</A>
if you have questions regarding this page
AddHead¶
Use this tag like the
PageTop header, but its contents will be added
between </TITLE> and </HEAD>.
Example:
AddHead[myrouter]: <link rev="made" href="mailto:mrtg@blabla.edu">
BodyTag¶
BodyTag lets you supply your very own <body ...> tag for the generated
webpages.
Example:
BodyTag[myrouter]: <BODY LEFTMARGIN="1" TOPMARGIN="1"
BACKGROUND="/stats/images/bg.neo2.gif">
AbsMax¶
If you are monitoring a link which can handle more traffic than the
MaxBytes value. Eg, a line which uses compression or some frame relay
link, you can use the
AbsMax keyword to give the absolute maximum value
ever to be reached. We need to know this in order to sort out unrealistic
values returned by the routers. If you do not set
AbsMax, rateup will
ignore values higher than
MaxBytes.
Example:
AbsMax[myrouter]: 2500000
Unscaled¶
By default each graph is scaled vertically to make the actual data visible even
when it is much lower than
MaxBytes. With the
Unscaled variable
you can suppress this. It's argument is a string, containing one letter for
each graph you don't want to be scaled: d=day w=week m=month y=year. There is
also a special case to unset the variable completely: n=none. This could be
useful in the event you need to override a global configuration. In the
example scaling for the yearly and the monthly graph are suppressed.
Example:
Unscaled[myrouter]: ym
WithPeak¶
By default the graphs only contain the average values of the monitored variables
- normally the transfer rates for incoming and outgoing traffic. The following
option instructs mrtg to display the peak 5 minute values in the [w]eekly,
[m]onthly and [y]early graph. In the example we define the monthly and the
yearly graph to contain peak as well as average values.
Examples:
WithPeak[myrouter]: ym
Suppress¶
By default mrtg produces 4 graphs. With this option you can suppress the
generation of selected graphs. The option value syntax is analogous to the
above two options. In this example we suppress the yearly graph as it is quite
empty in the beginning.
Example:
Suppress[myrouter]: y
Extension¶
By default, mrtg creates .html files. Use this option to tell mrtg to use a
different extension. For example you could set the extension to php3, then you
will be able to enclose PHP tags into the output (useful for getting a router
name out of a database).
Example:
Extension[myrouter]: phtml
Directory¶
By default, mrtg puts all the files that it generates for each target (the GIFs,
the HTML page, the log file, etc.) in
WorkDir.
If the
Directory option is specified, the files are instead put into a
directory under
WorkDir or Log-, Image- and HtmlDir). (For example the
Directory option below would cause all the files for a target myrouter
to be put into directory /usr/tardis/pub/www/stats/mrtg/myrouter/ .)
The directory must already exist; mrtg will not create it.
Example:
WorkDir: /usr/tardis/pub/www/stats/mrtg
Directory[myrouter]: myrouter
NOTE: the Directory option must always be 'relative' or bad things will happen.
Clonedirectory¶
If the
Directory option is specified, the
Clonedirectory option
will copy all the contents of
Directory to the
Clonedirectory.
Example:
WorkDir: /usr/tardis/pub/www/stats/mrtg
Directory[myrouter]: myrouter
Clonedirectory[myrouter]: myclonedirectory
Optionally the target name can be changed in the cloning process.
Example:
WorkDir: /usr/tardis/pub/www/stats/mrtg
Directory[myrouter]: myrouter
Clonedirectory[myrouter]: myclonedirectory mynewtarget
NOTE1: The clone directory must already exist; mrtg will not create it.
NOTE2: The Clonedirectory option must also always be 'relative' or bad things
will happen.
NOTE3: This requires the File::Copy module
XSize and YSize¶
By default mrtgs graphs are 100 by 400 pixels wide (plus some more for the
labels. In the example we get almost square graphs ...
Note: XSize must be between 20 and 600; YSize must be larger than 20
Example:
XSize[myrouter]: 300
YSize[myrouter]: 300
XZoom and YZoom¶
If you want your graphs to have larger pixels, you can "Zoom" them.
Example:
XZoom[myrouter]: 2.0
YZoom[myrouter]: 2.0
XScale and YScale¶
If you want your graphs to be actually scaled use
XScale and
YScale. (Beware: while this works, the results look ugly (to be frank)
so if someone wants to fix this: patches are welcome.
Example:
XScale[myrouter]: 1.5
YScale[myrouter]: 1.5
YTics and YTicsFactor¶
If you want to show more than 4 lines per graph, use YTics. If you want to scale
the value used for the YLegend of these tics, use YTicsFactor. The default
value for YTics is 4 and the default value for YTicsFactor is 1.0 .
Example:
Suppose you get values ranging from 0 to 700. You want to plot 7 lines and want
to show 0, 1, 2, 3, 4, 5, 6, 7 instead of 0, 100, 200, 300, 400, 500, 600,
700. You should write then:
YTics[myrouter]: 7
YTicsFactor[myrouter]: 0.01
Factor¶
If you want to multiply all numbers shown below the graph with a constant
factor, use this directive to define it ..
Example:
Factor[as400]: 4096
Step¶
Change the default step from 5 * 60 seconds to something else (I have not tested
this much ...)
Example:
Step[myrouter]: 60
PNGTitle¶
When using rateup for graph generation, this will print the given title in the
graph it generates.
Example:
PNGTitle[myrouter]: WAN Link UK-US
Options¶
The
Options Keyword allows you to set some boolean switches:
- growright
- The graph grows to the left by default. This option flips
the direction of growth causing the current time to be at the right edge
of the graph and the history values to the left of it.
- bits
- All the monitored variable values are multiplied by 8 (i.e.
shown in bits instead of bytes) ... looks much more impressive :-) It also
affects the 'factory default' labeling and units for the given
target.
- perminute
- All the monitored variable values are multiplied by 60
(i.e. shown in units per minute instead of units per second) in case of
small values more accurate graphs are displayed. It also affects the
'factory default' labeling and units for the given target.
- perhour
- All the monitored variable values are multiplied by 3600
(i.e. shown in units per hour instead of units per second) in case of
small values more accurate graphs are displayed. It also affects the
'factory default' labeling and units for the given target.
- noinfo
- Suppress the information about uptime and device name in
the generated webpage.
- nopercent
- Don't print usage percentages.
- transparent
- Make the background of the generated gifs transparent.
- integer
- Print summary lines below graph as integers without
commas.
- dorelpercent
- The relative percentage of IN-traffic to OUT-traffic is
calculated and displayed in the graph as an additional line. Note: Only a
fixed scale is available (from 0 to 100%). Therefore if IN-traffic is
greater than OUT-traffic then 100% is displayed. If you suspect that your
IN-traffic is not always less than or equal to your OUT-traffic you are
urged to not use this options. Note: If you use this option in combination
with the Colours options, a fifth colour-name colour-value pair is
required there.
- avgpeak
- There are some ISPs who use the average Peak values to bill
their customers. Using this option MRTG displays these values for each
graph. The value is built by averaging the max 5 minute traffic average
for each 'step' shown in the graph. For the Weekly graph this means that
it builds the average of all 2 hour intervals 5 minute peak values.
(Confused? Thought so!)
- gauge
- Treat the values gathered from target as 'current status'
measurements and not as ever incrementing counters. This would be useful
to monitor things like disk space, processor load, temperature, and the
like ...
In the absence of 'gauge' or 'absolute' options, MRTG treats variables as a
counters and calculates the difference between the current and the
previous value and divides that by the elapsed time between the last two
readings to get the value to be plotted.
- absolute
- This is for counter type data sources which reset their
value when they are read. This means that rateup does not have to build
the difference between the current and the last value read from the data
source. The value obtained is still divided by the elapsed time between
the current and the last reading, which makes it different from the
'gauge' option. Useful for external data gatherers.
- derive
- If you are using rrdtool as logger/grapher you can use a
third type of data source. Derive is like counter, except that it is not
required to go UP all the time. It is useful for situations where the
change of some value should be graphed.
- unknaszero
- Log unknown data as zero instead of the default behaviour
of repeating the last value seen. Be careful with this, often a flat line
in the graph is much more obvious than a line at 0.
- withzeroes
- Normally we ignore all values which are zero when
calculating the average transfer rate on a line. If this is not desirable
use this option.
- noborder
- If you are using rateup to log data, MRTG will create the
graph images. Normally these images have a shaded border around them. If
you do not want the border to be drawn, enable this option. This option
has no effect if you are not using rateup.
- noarrow
- As with the option above, this effects rateup graph
generation only. Normally rateup will generate graphs with a small arrow
showing the direction of the data. If you do not want this arrow to be
drawn, enable this option. This option has no effect if you are not using
rateup.
- noi
- When using rateup for graph generation, you can use this
option to stop rateup drawing a graph for the 'I' or first variable. This
also removes entries for this variable in the HTML page MRTG generates,
and will remove the peaks for this variable if they are enabled. This
allows you to hide this data, or can be very useful if you are only
graphing one line of data rather than two. This option is not destructive
- any data received for the the variable continued to be logged, it just
isn't shown.
- noo
- Same as above, except relating to the 'O' or second
variable.
- nobanner
- When using rateup for graph generation, this option
disables MRTG adding the MRTG banner to the HTML pages it generates.
- nolegend
- When using rateup for graph generation, this option will
stop MRTG from creating a legend at the bottom of the HTML pages it
generates.
- printrouter
- When using rateup for graph generation, this option will
print the router name in the graph it generates. This option is overridden
by the value of PNGTitle if one is given
- pngdate
- When using rateup for graph generation, this option will
print a timestamp in the graph it generates, including a timezone if one
is specified by the 'Timezone' parameter. This is aequivalent to setting
TimeStrPost[x]: RU
- logscale
- The logscale option causes rateup to display the
data with the Y axis scaled logarithmically. Doing so allows the normal
traffic to occupy the majority of the vertical range, while still showing
any spikes at their full height.
logscale displays all the available data and will always produce
well-behaved graphs. People often consider a logarithmically scaled graph
counterintuitive, however, and thus hard to interpret.
- expscale
- The expscale option causes rateup to display the
data with the Y axis scaled exponentially. Doing so emphasizes small
changes at the top of the scale; this can be useful when graphing values
that fluctuate by a small amount near the top of the scale, such as line
voltage.
expscale is essentially the inverse of logscale.
- secondmean
- The secondmean option sets the maximum value on the
graph to the mean of the data greater than the mean of all data. This
produces a graph that focuses more on the typical data, while clipping
large peaks.
Using secondmean will give a more intutive linearly scaled graph, but
can result in a uselessly high or low scale in some rare situations
(specifically, when the data includes a large portion of values far from
the actual mean)
If a target includes both logscale and secondmean in the
options, the secondmean takes precedence.
Example:
Options[myrouter]: growright, bits
kilo¶
Use this option to change the multiplier value for building prefixes.
Defaultvalue is 1000. This tag is for the special case that 1kB = 1024B, 1MB =
1024kB and so far.
Example:
kilo[myrouter]: 1024
kMG¶
Change the default multiplier prefixes (,k,M,G,T,P). In the tag
ShortLegend define only the basic units. Format: Comma separated list
of prefixed. Two consecutive commas or a comma at start or end of the line
gives no prefix on this item. If you do not want prefixes, just put two
consecutive commas. If you want to skip a magnitude select '-' as value.
Example: velocity in nm/s (nanometers per second) displayed in nm/h.
ShortLegend[myrouter]: m/h
kMG[myrouter]: n,u,m,,k,M,G,T,P
options[myrouter]: perhour
Colours¶
The
Colours tag allows you to override the default colour scheme. Note:
All 4 of the required colours must be specified here. The colour name
('Colourx' below) is the legend name displayed, while the RGB value is the
real colour used for the display, both on the graph and in the html doc.
Format is: Col1#RRGGBB,Col2#RRGGBB,Col3#RRGGBB,Col4#RRGGBB
Important: If you use the
dorelpercent options tag a fifth colour name
colour value pair is required:
Col1#RRGGBB,Col2#RRGGBB,Col3#RRGGBB,Col4#RRGGBB,Col5#RRGGBB
- Colour1
- First variable (normally Input) on default graph.
- Colour2
- Second variable (normally Output) on default graph.
- Colour3
- Max first variable (input).
- Colour4
- Max second variable (output).
- RRGGBB
- 2 digit hex values for Red, Green and Blue.
Example:
Colours[myrouter]: GREEN#00eb0c,BLUE#1000ff,DARK GREEN#006600,VIOLET#ff00ff
Background¶
With the
Background tag you can configure the background colour of the
generated HTML page.
Example:
Background[myrouter]: #a0a0a0a
YLegend, ShortLegend, Legend[1234]¶
The following keywords allow you to override the text displayed for the various
legends of the graph and in the HTML document:
- YLegend
- The Y-axis label of the graph. Note that a text which is
too long to fit in the graph will be silently ignored.
- ShortLegend
- The units string (default 'b/s') used for Max, Average and
Current
- Legend[1234IO]
- The strings for the colour legend.
Example:
YLegend[myrouter]: Bits per Second
ShortLegend[myrouter]: b/s
Legend1[myrouter]: Incoming Traffic in Bits per Second
Legend2[myrouter]: Outgoing Traffic in Bits per Second
Legend3[myrouter]: Maximal 5 Minute Incoming Traffic
Legend4[myrouter]: Maximal 5 Minute Outgoing Traffic
LegendI[myrouter]: In:
LegendO[myrouter]: Out:
Note, if
LegendI or
LegendO are set to an empty string with
LegendO[myrouter]:
The corresponding line below the graph will not be printed at all.
Timezone¶
If you live in an international world, you might want to generate the graphs in
different timezones. This is set in the TZ variable. Under certain operating
systems like Solaris, this will provoke the localtime call to give the time in
the selected timezone.
Example:
Timezone[myrouter]: Japan
The Timezone is the standard timezone of your system, ie Japan, Hongkong, GMT,
GMT+1 etc etc.
By default, mrtg (actually rateup) uses the
strftime(3) '%V' option to
format week numbers in the monthly graphs. The exact semantics of this format
option vary between systems. If you find that the week numbers are wrong, and
your system's
strftime(3) routine supports it, you can try another
format option. The POSIX '%V' option correspond to the widely used ISO 8601
week numbering standard. The week format character should be specified as a
single letter; either W, V, or U.
The UNIX version of rateup uses the libc implementation of strftime. On Windows,
the native strftime implementation does not know about %V. So there we use a
different implementation of strftime that does support %V.
Example:
Weekformat[myrouter]: W
RRDRowCount¶
This affects the creation of new rrd files. By default rrds are created to hold
about 1 day's worth of high resolution data. (plus 1 week of 30 minute data, 2
months of 2 hour data and 2 years of 1 day data). With this Keyword you can
change the number of base interval entries configured for new rrds as they get
created. Note that you must take the interval time into account.
Example:
RRDRowCount[myrouter]: 1600
RRDRowCount30m¶
As per RRDRowCount, but for the RRA's -typically- used for 30 minute data. Even
so, you must still take the base interval into account. Leaving out this
keyword will force the old default of 800 rows.
Example:
RRDRowCount30m[myrouter]: 800
RRDRowCount2h¶
As per RRDRowCount, but for the RRA's -typically- used for 2 hour data. Even so,
you must still take the base interval into account. Leaving out this keyword
will force the old default of 800 rows.
Example:
RRDRowCount2h[myrouter]: 400
RRDRowCount1d¶
As per RRDRowCount, but for the RRA's -typically- used for 1 day data. Even so,
you must still take the base interval into account. Leaving out this keyword
will force the old default of 800 rows.
Example:
RRDRowCount1d[myrouter]: 200
RRDHWRRAs¶
Normally the RRDs created by MRTG will just contain the information gathered
directly from the respective target. With this option you can tap into
rrdtools advanced aberrant behaviour detection module based on Holt-Winters
forecasting. The RRDHWRRAs property specifies the Holt-Winters RRAs as
described in the rrdcreate manual page.
Note, this setting will only affect newly created RRDs (targets).
Example:
RRDHWRRAs[myrouter]: RRA:HWPREDICT:1440:0.1:0.0035:288
TimeStrPos¶
This defines placement of the timestamp string on the image. Possible values are
RU, LU, RL, LL (which stand, respectively, for RightUpper, LeftUpper,
RightLower and LeftLower corner) and NO (for no timestamp). By default, no
timestamp is placed on the image.
Example:
TimeStrPos[myrouter]: RU
TimeStrFmt¶
Using this keyword you may specify format of the timestamp to be placed on the
image (if enabled by the TimeStrPos keyword). Specified string will be used by
the
strftime() function - see
strftime(3) documentation for
conversion specifiers available on your system. Default format: %Y-%m-%d %H:%M
Example:
TimeStrFmt[myrouter]: %H:%M:%S
THRESHOLD CHECKING¶
Through its threshold checking functionality mrtg is able to detect threshold
problems for the various targets and can call external scripts to handle those
problems (e.g. send email or a page to an administrator).
Threshold checking is configured through the following parameters:
ThreshDir (GLOBAL)¶
By defining ThreshDir to point to a writable directory, MRTG will only alert you
when a threshold boundary has been crossed.
Example:
ThreshDir: /var/mrtg/thresh
ThreshHyst (GLOBAL)¶
If a threshold is broken, and you have a threshdir defined, then mrtg will send
mail once the threshold becomes 'unborken' to avoid situations where broken
and unbroken messages get sent in close succession, we only send an unbroken
message once the curent value is 0.1 (10%) away from the threshold. using the
ThreshHyst config variable you can customize this value.
Example for 5%:
ThreshHyst: 0.05
ThreshMailServer (GLOBAL)¶
Adderss of an SMTP server which is going to accept mail about Thresholds being
broken and unbroken.
ThreshMailSender (GLOBAL)¶
What is the sender address of the threshold mail.
Example:
ThreshMailSender: mrtg@example.com
ThreshMailAddress (PER TARGET)¶
Email address for Threshold related Mails. This will only work if a mailserver
has been configured.
Example:
ThreshMailAddress[_]: admin@example.com
ThreshMailAddress[router]:
This would bring threshold releaed mail to all but the target called 'router'.
ThreshMinI (PER TARGET)¶
This is the minimum acceptable value for the Input (first) parameter. If the
parameter falls below this value, the program specified in ThreshProgI will be
run and a mail will be sent to the ThreshMailAddress if specified. If the
value ends in '%' then the threshold is defined relative to MaxBytes.
ThreshMaxI (PER TARGET)¶
Works the same as TheshMinI but it acts when the value is higher than
ThreshMaxI.
ThreshDesc (PER TARGET)¶
Its value will be assigned to the environment variable THRESH_DESC before any of
the programs mentioned below are called. The programs can use the value of
this variable to produce more user-friendly output.
ThreshProgI (PER TARGET)¶
This defines a program to be run if ThreshMinI or ThreshMaxI is broken. MRTG
passes 3 arguments: the $router variable, the threshold value broken, and the
current parameter value.
ThreshProgOKI (PER TARGET)¶
This defines a program to be run if the parameter is currently OK (based on
ThreshMinI and ThreshMaxI), but wasn't OK on the previous running -- based on
the files found in ThreshDir. MRTG passes 3 arguments: the $router variable
the unbroken threshold value, and the current parameter value.
ThreshMinO, ThreshMaxO, ThreshProgO, and ThreshProgOKO¶
These work the same as their *I counterparts, except on the Output (second)
parameter.
SetEnv¶
When calling threshold scripts from within your cfg file you might want to pass
some data on to the script. This can be done with the SetEnv configuration
option which takes a series of environment variable assignments. Note that the
quotes are mandatory. This does not work for external scripts. It is not
possible to set environment variables per target.
Example:
SetEnv[myrouter]: EMAIL="contact_email@someplace.net"
HOST="www.some_server.net"
HW Failure Bassed Threshold Checking¶
When using rrd based logging with HW RRAs defined. You can use the confidence
bounds violations stored in the FAILURES RRA for threshold based alerts.
There the all target specific threshold variables have a Hold-Winters
counterpart:
ThreshMailAddress -> HWThreshMailAddress
ThreshMinI -> HWThreshMinI
...
The global variables for threshold checking are shared except for the
ThreshHyst -> HWThreshHyst
And HWThreshDesc sets the HWTHRESH_DESC variable.
PER TARGET DEFAULT VALUES¶
Pre- and Postfix¶
To save yourself some typing you can define a target called '^'. The text of
every Keyword you define for this target will be PREPENDED to the
corresponding Keyword of all the targets defined below this line. The same
goes for a Target called '$' but its text will be APPENDED.
Note that a space is inserted between the prepended text and the Keyword value,
as well as between the Keyword value and the appended text. This works well
for text-valued Keywords, but is not very useful for other Keywords. See the
"default" target description below.
The example will make mrtg use a common header and a common contact person in
all the pages generated from targets defined later in this file.
Example:
PageTop[^]: <H1>NoWhere Unis Traffic Stats</H1><HR>
PageTop[$]: Contact Peter Norton if you have any questions<HR>
To remove the prepend/append value, specify an empty value, e.g.:
PageTop[^]:
PageTop[$]:
NoSpaceChar¶
With PREPEND and APPEND (see below) there is normally a space inserted between
the local value and the PRE- or APPEND value. Sometimes this is not desirable.
You can use the global option
NoSpaceChar to define a character which
can be mentioned at the end of a $ or ^ definition in order to supress the
space.
Example:
NoSpaceChar: ~
Target[^]: 1.3.6.1.4.1.482.50.2.4.20.0&1.3.6.1.4.1.482.50.2.4.21.0:get@~
Target[a]: a.tolna.net
Target[b]: b.tolna.net
Target[c]: c.tolna.net
Target[d]: d.tolna.net
Default Values¶
The target name '_' specifies a default value for that Keyword. In the absence
of explicit Keyword value, the prepended and the appended keyword value, the
default value will be used.
Example:
YSize[_]: 150
Options[_]: growright,bits,nopercent
WithPeak[_]: ymw
Suppress[_]: y
MaxBytes[_]: 1250000
To remove the default value and return to the 'factory default', specify an
empty value, e.g.:
YLegend[_]:
There can be several instances of setting the default/prepend/append values in
the configuration file. The later setting replaces the previous one for the
rest of the configuration file. The default/prepend/append values used for a
given keyword/target pair are the ones that were in effect at the point in the
configuration file where the target was mentioned for the first time.
Example:
MaxBytes[_]: 1250000
Target[myrouter.somplace.edu.2]: 2:public@myrouter.somplace.edu
MaxBytes[_]: 8000
Title[myrouter.somplace.edu.2]: Traffic Analysis for myrouter.somplace.edu IF 2
The default
MaxBytes for the target myrouter.someplace.edu.2 in the above
example will be 1250000, which was in effect where the target name
myrouter.someplace.edu.2 first appeared in the config file.
COMMAND LINE OPTIONS¶
- --user username and --group
groupname
- Run as the given user and/or group. (Unix Only)
- --lock-file filename
- Use an alternate lock-file (the default is to use the
configuration-file appended with "_l").
- --confcache-file filename
- Use an alternate confcache-file (the default is to use the
configuration-file appended with ".ok")
- --logging filename|eventlog
- If this is set to writable filename, all output from mrtg
(warnings, debug messages, errors) will go to filename. If you are
running on Win32 you can specify eventlog instead of a filename
which will send all error to the windows event log.
NOTE: Note, there is no Message DLL for mrtg included with mrtg.
This has the side effect that the windows event logger will display a nice
message with every entry in the event log, complaing about the fact that
mrtg has no message dll. If you go to the mrtg contrib download area (on
the website) you will find the mrtg-message-dll.zip which does contain
such a thing.
- --daemon
- Put MRTG into the background, running as a daemon. This
works the same way as the config file option, but the switch is required
for proper FHS operation (because /var/run is writable only by root)
- --fhs
- Configure all mrtg paths to conform to the FHS
specification; http://www.pathname.com/fhs/
- --check
- Only check the cfg file for errors. Do not do
anything.
- --pid-file=s
- Define the name and path of the pid file for mrtg running
as a daemon
- --debug=s
- Enable debug options. The argument of the debug option is a
comma separated list of debug values:
cfg - watch the config file reading
dir - directory mangeling
base - basic program flow
tarp - target parser
snpo - snmp polling
coca - confcache operations
fork - forking view
time - some timing info
log - logging of data via rateup or rrdtool
eval - print eval strings before evaluting them
prof - add hires timing info the rrd calls
Example:
--debug="cfg,snpo"
EXIT CODES¶
An exit code of 0 indicates that all targets were successful. Generally
speaking, most codes greater than 0 indicate that there was an unrecoverable
problem. One exception to this is code 91, which indicates that at least one
of the targets was successful. A partial listing of the codes follows:
0: All targets sucessful
2: Config error (can't read, fatal error in config, etc)
17: Another MRTG process is processing config
91: At least one target sucessful
92: No targets were sucessful
EXAMPLES¶
Minimal mrtg.cfg¶
WorkDir: /usr/tardis/pub/www/stats/mrtg
Target[r1]: 2:public@myrouter.somplace.edu
MaxBytes[r1]: 8000
Title[r1]: Traffic Analysis ISDN
PageTop[r1]: <H1>Stats for our ISDN Line</H1>
Cfg for several Routers.¶
WorkDir: /usr/tardis/pub/www/stats/mrtg
Title[^]: Traffic Analysis for
PageTop[^]: <H1>Stats for
PageTop[$]: Contact The Chief if you notice anybody<HR>
MaxBytes[_]: 8000
Options[_]: growright
Title[isdn]: our ISDN Line
PageTop[isdn]: our ISDN Line</H1>
Target[isdn]: 2:public@router.somplace.edu
Title[backb]: our Campus Backbone
PageTop[backb]: our Campus Backbone</H1>
Target[backb]: 1:public@router.somplace.edu
MaxBytes[backb]: 1250000
# the following line removes the default prepend value
# defined above
Title[^]:
Title[isdn2]: Traffic for the Backup ISDN Line
PageTop[isdn2]: our ISDN Line</H1>
Target[isdn2]: 3:public@router.somplace.edu
AUTHOR¶
Tobias Oetiker <tobi@oetiker.ch> and many contributors