NAME
Smokeping::probes::basefork - Yet Another Base Class for implementing
SmokePing Probes
OVERVIEW
Like Smokeping::probes::basevars, but supports the probe-specific
property ‘forks’ to determine how many processes should be run
concurrently. The targets are pinged one at a time, and the number of
pings sent can vary between targets.
SYNOPSIS
*** Probes ***
+basefork
forks = 5
offset = 50%
step = 300
timeout = 15
# The following variables can be overridden in each target section
pings = 5
# [...]
*** Targets ***
probe = basefork # if this should be the default probe
# [...]
+ mytarget
# probe = basefork # if the default probe is something else
host = my.host
pings = 5
DESCRIPTION
Not all pinger programs support testing multiple hosts in a single go
like fping(1). If the measurement takes long enough, there may be not
enough time perform all the tests in the time available. For example,
if the test takes 30 seconds, measuring ten hosts already fills up the
SmokePing default five minute step.
Thus, it may be necessary to do some of the tests concurrently. This
module defines the ping method that forks the requested number of
concurrent processes and calls the pingone method that derived classes
must provide.
The pingone method is called with one argument: a hash containing the
target that is to be measured. The contents of the hash are described
in Smokeping::probes::basevars(3pm).
The number of concurrent processes is determined by the probe-specific
variable ‘forks’ and is 5 by default. If there are more targets than
this value, another round of forks is done after the first processes
are finished. This continues until all the targets have been tested.
The timeout in which each child has to finish is set to 5 seconds
multiplied by the maximum number of ’pings’ of the targets. You can set
the base timeout differently if you want to, using the timeout property
of the probe in the master config file (this again will be multiplied
by the maximum number of pings). The probe itself can also provide
another default value if desired by modifying the _default value of the
timeout variable.
If the child isn’t finished when the timeout occurs, it will be killed
along with any processes it has started.
The number of pings sent can be specified in the target-specific
variable ’pings’.
VARIABLES
Supported probe-specific variables:
forks
Run this many concurrent processes at maximum
Example value: 5
Default value: 5
offset
If you run many probes concurrently you may want to prevent them
from hitting your network all at the same time. Using the probe-
specific offset parameter you can change the point in time when
each probe will be run. Offset is specified in % of total interval,
or alternatively as ’random’, and the offset from the ’General’
section is used if nothing is specified here. Note that this does
NOT influence the rrds itself, it is just a matter of when data
acqusition is initiated. (This variable is only applicable if the
variable ’concurrentprobes’ is set in the ’General’ section.)
Example value: 50%
step
Duration of the base interval that this probe should use, if
different from the one specified in the ’Database’ section. Note
that the step in the RRD files is fixed when they are originally
generated, and if you change the step parameter afterwards, you’ll
have to delete the old RRD files or somehow convert them. (This
variable is only applicable if the variable ’concurrentprobes’ is
set in the ’General’ section.)
Example value: 300
timeout
How long a single ’ping’ takes at maximum
Example value: 15
Default value: 5
Supported target-specific variables:
pings
How many pings should be sent to each target, if different from the
global value specified in the Database section. Note that the
number of pings in the RRD files is fixed when they are originally
generated, and if you change this parameter afterwards, you’ll have
to delete the old RRD files or somehow convert them.
Example value: 5
AUTHORS
Niko Tyni <ntyni@iki.fi>
SEE ALSO
Smokeping::probes::basevars, Smokeping::probes::EchoPing
2.3.6 2010-01-0doc::Smokeping::probes::basefork(3)