Mod Gearman – ConSol* Labs
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Mod Gearman
Posted on September 13th, 2010 by sven
What is Mod-Gearman
is an easy way
of distributing active Nagios checks across your network and
increasing Nagios scalability. Mod-Gearman can even help to reduce the
load on a single Nagios host, because its much smaller and more
efficient in executing checks.
It consists of three parts:
There is a NEB module which resides in the Nagios core and adds servicechecks,
hostchecks and eventhandler to a Gearman queue.
The counterpart is one or more worker clients executing the checks.
Worker can be configured to only run checks for specific host- or
servicegroups.
And you need at least one
for some examples.
Presentations
Reduce load of your central Nagios machine
Make Nagios scalable up to thousands of checks per second
Easy distributed setups without configuration overhead
Real loadbalancing across all workers
Real failover for redundant workers
Embedded Perl support for very fast execution of perl scripts
Fast transport of passive check results with included tools like
send_gearman and send_multi
Latest stable for Naemon , released January 20 2015
Latest stable for Nagios 3 , released January 20 2015
Mod Gearman is available for download at:
Source is available on GitHub:
Older versions are available in the .
Mod-Gearman is also included in .
Debian users should use the
SLES/RHEL/Centos users should use the
Debian/Ubuntu users might also want to check out the
Professional support and consulting is available via
Mod-Gearman has been succesfully tested with latest Nagios.
for details.
There are no known bugs at the moment. Let me know if you find one.
The changelog is available on
How does it work
When the Mod-Gearman broker module is loaded, it intercepts all
servicechecks, hostchecks and the eventhandler events. Eventhandler
are then sent to a generic eventhandler queue. Checks for hosts
which are in one of the specified hostgroups, are sent into a seperate
hostgroup queue. All non matching hosts are sent to a generic hosts
Checks for services are first checked against the list of
servicegroups, then against the hostgroups and if none matches they
will be sent into a generic service queue. The NEB module starts a
single thread, which monitors the check_results where all results
A simple example queue would look like:
+---------------+------------------+--------------+--------------+
| Queue Name
| Worker Available | Jobs Waiting | Jobs Running |
+---------------+------------------+--------------+--------------+
| check_results | 1
| eventhandler
| host
| service
+---------------+------------------+--------------+--------------+
There is one queue for the results and two for the checks plus the
eventhandler queue.
The workflow is simple:
Nagios wants to execute a service check.
The check is intercepted by the Mod-Gearman neb module.
Mod-Gearman puts the job into the service queue.
A worker grabs the job and puts back the result into the
check_results queue
Mod-Gearman grabs the result job and puts back the result onto the
check result list
The Nagios reaper reads all checks from the result list and
updates hosts and services
You can set some host or servicegroups for special worker. This
example uses a seperate hostgroup for Japan and a seperate
servicegroup for resource intensive selenium checks.
It would look like this:
+-----------------------+------------------+--------------+--------------+
| Queue Name
| Worker Available | Jobs Waiting | Jobs Running |
+-----------------------+------------------+--------------+--------------+
| check_results
| eventhandler
| host
| hostgroup_japan
| service
| servicegroup_selenium | 2
+-----------------------+------------------+--------------+--------------+
You still have the generic queues and in addition there are two queues
for the specific groups.
The worker processes will take jobs from the queues and put the result
back into the check_result queue which will then be taken back by the
neb module and put back into the Nagios core. A worker can work on one
or more queues. So you could start a worker which only handles the
hostgroup_japan group.
One worker for the selenium checks and one
worker which covers the other queues. There can be more than one
worker on each queue to share the load.
Common Scenarios
Load Balancing
The easiest variant is a simple load balancing. For example if your
single Nagios box just cannot handle the load, you could just add a
worker in the same network (or even on the same host) to reduce your
load on the Nagios box. Therefor we just enable hosts, services and
eventhandler on the server and the worker.
reduced load on your monitoring box
no failover
Distributed Monitoring
If your checks have to be run from different network segments, then
you can use the hostgroups (or servicegroups) to define a hostgroup
for specific worker. The general hosts and services queue is disabled
for this worker and just the hosts and services from the given
hostgroup will be processed.
reduced load on your monitoring box
ability to access remote networks
no failover
Distributed Monitoring with Load Balancing
Your distributed setup could easily be extended to a load balanced
setup with just adding more worker of the same config.
reduced load on your monitoring box
ability to access remote networks
automatic failover and load balancing for worker
no failover for the master
NSCA Replacement
If you just want to replace a current NSCA solution, you could load
the Mod-Gearman NEB module and disable all distribution features. You
still can receive passive results by the core send via
send_gearman / send_multi. Make sure you use the same encryption
settings like the neb module or your core won’t be able to process the
results or use the accept_clear_results option.
easy to setup in existing environments
Distributed Setup With Remote Scheduler
In case your network is unstable or you need a gui view from the
remote location or any other reason which makes a remote core
unavoidable you may want this setup. Thist setup consists of 2
independent Mod-Gearman setups and the slave worker just send their
results to the master via the dup_server option. The master
objects configuration must contain all slave services and hosts.
The configuration sync is not part of Mod-Gearman.
independent from network outtakes
local view
more complex setup
requires configuration sync
Gearman Proxy
Sometimes you may need to reverse the direction of the initial
connection attempt. Usually the worker and the neb module open the
initial connection so they need to access the gearmand port. In cases
where no direct connection is possible use ssh tunnel or the Gearman
proxy. The Gearman proxy just puts jobs from one gearmand into another
gearmand and vice versa.
Just copy the gearman_proxy.pl from the contrib or share directory and
adjust the first few lines to match you needs.
changes direction of initial connection setup
buffers network outages
two more daemon to monitor and maintain
Installation
Using OMD is propably the easiest way of installing and using
Mod-Gearman. You just have to run omd config or set Mod-Gearman
OMD is available for Debian, Ubuntu, Centos/Redhat and SLES.
OMD[test]:~$ omd config set MOD_GEARMAN on
Mod-Gearman is included in
since version 0.48.
Debian / Ubuntu
It is strongly recommended to use the
contains Debian Squeeze and various Ubuntu packages.
Centos/Redhat
The easy and proper way is to build RPM packages. The following steps
assume a Centos 5.7. Other releases may have different versions but
should behave similar.
available.
Build/install Gearmand rpms
#> yum install autoconf automake libtool boost141-devel boost141-program-options
#> cd /tmp
#> wget http://launchpad.net/gearmand/trunk/0.33/+download/gearmand-0.33.tar.gz
#> tar zxf gearmand-0.33.tar.gz
#> ln -s gearmand-0.33/support/gearmand.init /tmp/gearmand.init
#> vi gearmand-0.33/support/gearmand.spec
change in line 9 and 25:
Requires: sqlite, libevent >= 1.4, boost-program-options >=
Requires: sqlite, libevent >= 1.4, boost141-program-options >=
#> tar cfz gearmand-0.33.tar.gz gearmand-0.33
#> LIBRARY_PATH=/usr/lib64/boost141:/usr/lib/boost141 \
LD_LIBRARY_PATH=/usr/lib64/boost141:/usr/lib/boost141 \
CPATH=/usr/include/boost141 \
rpmbuild -tb gearmand-0.33.tar.gz
#> yum --nogpgcheck install /usr/src/redhat/RPMS/*/gearmand*-0.33-1*.rpm
The link to gearmand.init is a workaround, otherwise the build
will fail. It may not be necessary for future gearman versions.
Build/install Mod-Gearman rpms
#> wget http://labs.consol.de/wp-content/uploads/2010/09/mod_gearman-1.2.0.tar.gz
#> rpmbuild -tb mod_gearman-1.2.0.tar.gz
#> yum --nogpgcheck install /usr/src/redhat/RPMS/*/mod_gearman-1.2.0-1.*.rpm
Finally start and check your installation
#> /etc/init.d/gearmand start
#> /etc/init.d/mod_gearman_worker start
#> gearman_top
From Source
source installation should be avoided if possible. Prebuild packages are way easier to maintain.
Pre Requirements:
autoconf / automake / autoheader
libgearman (>= 0.14)
Download the tarball and perform the following steps:
#> ./configure
#> make
#> make install
Then add the mod_gearman.o to your Nagios installation and add a
broker line to your nagios.cfg:
broker_module=.../mod_gearman.o server=localhost:4730 eventhandler=yes services=yes hosts=yes config=.../module.conf
for details on all parameters
The next step is to start one or more worker. You may use the same
configuration file as for the neb module.
./mod_gearman_worker --server=localhost:4730 --services --hosts
or use the supplied init script.
Make sure you have started your Gearmand job server. Usually
it can be started with
/usr/sbin/gearmand -t 10 -j 0
or a supplied init script (extras/gearmand-init). Command line
arguments have change in recent gearman versions and you now should
use something like:
/usr/sbin/gearmand --threads=10 --job-retries=0
Patch Nagios
The needed patch is already applied to Nagios 3.2.2. Use the patch if you
have an older version.
It is not possible to distribute eventhandler with Nagios versions
prior 3.2.2. Just apply the patch from the ./extras/patches directory
to your Nagios sources and build Nagios again if you want to use an
older version. You only need to replace the Nagios binary. Nothing
else has changed. If you plan to distribute only Host/Servicechecks,
no patch is needed.
Configuration
Nagios Core
A sample broker in your nagios.cfg could look like:
broker_module=/usr/local/share/nagios/mod_gearman.o keyfile=/usr/local/share/nagios/secret.txt server=localhost eventhandler=yes hosts=yes services=yes config=.../module.conf
See the following list for a detailed explanation of available
Common Options
Shared options for worker and the NEB module:
include config from this file. Options are the same as described here.
include is an alias for config.
config=/etc/nagios3/mod_gm_worker.conf
use debug to increase the verbosity of the module.
Possible values are:
– only errors
1-4 – debug verbosity
– trace and all gearman related logs are going to stdout
Default is 0.
set way of logging.
Possible values are:
automatic – logfile when a logfile is specified. stdout when
no logfile is given.
stdout for tools.
– just print all messages to stdout
– use syslog for all log events
– use logfile
– use Nagios internal loging (not thread safe! Use
with care)
Default is automatic.
logmode=automatic
Path to the logfile.
logfile=/path/to/log.file
sets the address of your gearman job server. Can be specified
more than once to add more server. Mod-Gearman uses
the first server available.
server=localhost:4730,remote_host:4730
eventhandler
defines if the module should distribute execution of
eventhandlers.
eventhandler=yes
defines if the module should distribute execution of service checks.
services=yes
defines if the module should distribute execution of host checks.
hostgroups
sets a list of hostgroups which will go into seperate queues.
hostgroups=name1,name2,name3
servicegroups
sets a list of servicegroups which will go into seperate queues.
servicegroups=name1,name2,name3
encryption
enables or disables encryption. It is strongly advised to not disable
encryption. Anybody will be able to inject packages to your worker. Encryption
is enabled by default and you have to explicitly disable it. When using
encryption, you will either have to specify a shared password with key=... or
a keyfile with keyfile=....
Default is On.
encryption=yes
A shared password which will be used for encryption of data pakets. Should be at
least 8 bytes long. Maximum length is 32 characters.
key=secret
The shared password will be read from this file. Use either key or keyfile.
Only the first 32 characters from the first line will be used.
Whitespace to the right will be trimmed.
keyfile=/path/to/secret.file
use_uniq_jobs
Using uniq keys prevents the gearman queues from filling up when there
is no worker. However, gearmand seems to have problems with the uniq
key and sometimes jobs get stuck in the queue. Set this option to off
when you run into problems with stuck jobs but make sure your worker
are running.
Default is On.
use_uniq_jobs=on
Server Options
Additional options for the NEB module only:
localhostgroups
sets a list of hostgroups which will not be executed by gearman. They are just
passed through.
localhostgroups=name1,name2,name3
localservicegroups
sets a list of servicegroups which will not be executed by gearman. They are
just passed through.
localservicegroups=name1,name2,name3
queue_custom_variable
Can be used to define the target queue by a custom variable in
addition to host/servicegroups. When set for ex. to WORKER you then
could define a _WORKER custom variable for your hosts and services
to directly set the worker queue. The host queue is inherited unless
overwritten by a service custom variable. Set the value of your custom
variable to local to bypass Mod-Gearman (Same behaviour as in
localhostgroups/localservicegroups).
queue_custom_variable=WORKER
do_hostchecks
Set this to no if you want Mod-Gearman to only take care of
servicechecks. No hostchecks will be processed by Mod-Gearman. Use
this option to disable hostchecks and still have the possibility to
use hostgroups for easy configuration of your services.
If set to yes, you still have to define which hostchecks should be
processed by either using hosts or the hostgroups option.
Default: yes
do_hostchecks=yes
result_workers
Number of result worker threads. Usually one is enough. You may increase the
value if your result queue is not processed fast enough.
result_workers=3
Defines if the module should distribute perfdata to gearman.
perfdata=yes
processing of perfdata is not part of mod_gearman. You will need
additional worker for handling performance data. For example:
. Performance data is just
written to the gearman queue.
perfdata_mode
There will be only a single job for each host or servier when putting
performance data onto the perfdata_queue in overwrite mode. In
append mode perfdata will be stored as long as there is memory
left. Setting this to overwrite helps preventing the perf_data
queue from getting to big. Monitor your perfdata carefully when
using the append mode.
Possible values are:
1 – overwrite
2 – append
Default is 1.
perfdata_mode=1
result_queue
sets the result queue. Necessary when putting jobs from several Nagios instances
onto the same gearman queues. Default: check_results
result_queue=check_results_nagios1
orphan_host_checks
The Mod-Gearman NEB module will submit a fake result for orphaned host
checks with a message saying there is no worker running for this
queue. Use this option to get better reporting results, otherwise your
hosts will keep their last state as long as there is no worker
Default is yes.
orphan_host_checks=yes
orphan_service_checks
Same like orphan_host_checks but for services.
Default is yes.
orphan_service_checks=yes
accept_clear_results
When enabled, the NEB module will accept unencrypted results too. This
is quite useful if you have lots of passive checks and make use of
send_gearman/send_multi where you would have to spread the shared key
to all clients using these tools.
Default is no.
accept_clear_results=yes
Worker Options
Additional options for worker:
identifier
Identifier for this worker. Will be used for the worker_identifier queue for
status requests. You may want to change it if you are using more than one worker
on a single host.
Defaults to the current hostname.
identifier=hostname_test
Path to the pidfile.
pidfile=/path/to/pid.file
job_timeout
Default job timeout in seconds. Currently this value is only used for
eventhandler. The worker will use the values from the core for host
and service checks.
Default: 60
job_timeout=60
Threshold for discarding too old jobs. When a new job is older than
this amount of seconds it will not be executed and just discarded.
This will result in a message like “(Could Not Start Check In Time)”.
Possible reasons for this are time differences between core and
worker (use NTP!) or the smart rescheduler of the core which should be
disabled. Set to zero to disable this check.
Default: 0
max-age=600
min-worker
Minimum number of worker processes which should run at any time. Default: 1
min-worker=1
max-worker
Maximum number of worker processes which should run at any time. You may set
this equal to min-worker setting to disable dynamic starting of workers. When
setting this to 1, all services from this worker will be executed one after
another. Default: 20
max-worker=20
spawn-rate
Defines the rate of spawned worker per second as long as there are jobs
waiting. Default: 1
spawn-rate=1
load_limit1
Set a limit based on the 1min load average. When exceding the load limit,
no new worker will be started until the current load is below the limit.
No limit will be used when set to 0.
Default: no limit
load_limit1=0
load_limit5
Set a limit based on the 5min load average. See load_limit1 for details.
Default: no limit
load_limit5=0
load_limit15
Set a limit based on the 15min load average. See load_limit1 for details.
Default: no limit
load_limit15=0
idle-timeout
Time in seconds after which an idling worker exits. This parameter
controls how fast your waiting workers will exit if there are no jobs
waiting. Set to 0 to disable the idle timeout. Default: 10
idle-timeout=30
Controls the amount of jobs a worker will do before he exits. Use this to
control how fast the amount of workers will go down after high load times.
Disabled when set to 0. Default: 1000
max-jobs=500
fork_on_exec
Use this option to disable an extra fork for each plugin execution.
Disabling this option will reduce the load on the worker host, but may
cause trouble with unclean plugins. Default: no
fork_on_exec=no
sets the address of gearman job server where duplicated result will be sent to.
Can be specified more than once to add more server. Useful for duplicating
results for a reporting installation or remote gui.
dupserver=logserver:4730,logserver2:4730
show_error_output
Use this option to show stderr output of plugins too. When set to no,
only stdout will be displayed.
Default is yes.
show_error_output=yes
timeout_return
Defines the return code for timed out checks. Accepted return codes
are 0 (Ok), 1 (Warning), 2 (Critical) and 3 (Unknown)
Default: 2
timeout_return=2
dup_results_are_passive
Use this option to set if the duplicate result send to the dupserver
will be passive or active.
Default is yes (passive).
dup_results_are_passive=yes
debug-result
When enabled, the hostname of the executing worker will be put in
front of the plugin output. This may help with debugging your plugin
Default is off.
debug-result=yes
enable_embedded_perl
When embedded perl has been compiled in, you can use this
switch to enable or disable the embedded perl interpreter.
for details on EPN.
enable_embedded_perl=on
use_embedded_perl_implicitly
Default value used when the perl script does not have a
“nagios: +epn” or “nagios: -epn” set.
Perl scripts not written for epn support usually fail with epn,
so its better to set the default to off.
use_embedded_perl_implicitly=off
use_perl_cache
Cache compiled perl scripts. This makes the worker process a little
bit bigger but makes execution of perl scripts even faster.
When turned off, Mod-Gearman will still use the embedded perl
interpreter, but will not cache the compiled script.
use_perl_cache=on
restrict_path
‘restrict_path` allows you to restrict this worker to only execute plugins
from these particular folders. Can be used multiple times to specify more
than one folder.
Note that when this restriction is active, no shell will be spawned and
no shell characters ($&();<>`”’|) are allowed in the command line itself.
restrict_path=/usr/local/plugins/
workaround_rc_25
Duplicate jobs from gearmand result sometimes in exit code 25 of
plugins because they are executed twice and get killed because of
using the same ressource. Sending results (when exit code is 25 )
will be skipped with this enabled.
Only needed if you experience problems with plugins exiting with exit
code 25 randomly. Default is off.
workaround_rc_25=off
Queue Names
You may want to watch your gearman server job queue. The shipped
gearman_top does this. It polls the gearman server every second
and displays the current queue statistics.
+-----------------------+--------+-------+-------+---------+
| Name
| Worker | Avail | Queue | Running |
+-----------------------+--------+-------+-------+---------+
| check_results
| host
| service
| eventhandler
| servicegroup_jmx4perl | 3
| hostgroup_japan
+-----------------------+--------+-------+-------+---------+
check_results
this queue is monitored by the neb module to fetch results from the
worker. You don’t need an extra worker for this queue. The number of
result workers can be set to a maximum of 256, but usually one is
enough. One worker is capable of processing several thousand results
per second.
This is the queue for generic host checks. If you enable host checks
with the hosts=yes switch. Before a host goes into this queue, it is
checked if any of the local groups matches or a seperate hostgroup
machtes. If nothing matches, then this queue is used.
This is the queue for generic service checks. If you enable service
checks with the services=yes switch. Before a service goes into this
queue it is checked against the local host- and service-groups. Then
the normal host- and servicegroups are checked and if none matches,
this queue is used.
hostgroup_<name>
This queue is created for every hostgroup which has been defined by
the hostgroups=… option. Make sure you have at least one worker for
every hostgroup you specify. Start the worker with --hostgroups=...
to work on hostgroup queues. Note that this queue may also contain
service checks if the hostgroup of a service matches.
servicegroup_<name>
This queue is created for every servicegroup which has been defined by
the servicegroup=... option.
eventhandler
This is the generic queue for all eventhandler. Make sure you have a
worker for this queue if you have eventhandler enabled. Start the
worker with --events to work on this queue.
This is the generic queue for all performance data. It is created and
used if you switch on --perfdata=yes. Performance data cannot be
processed by the gearman worker itself. You will need
Performance
While the main motivation was to ease distributed configuration, this
plugin also helps to spread the load on multiple worker. Throughput is
mainly limited by the amount of jobs a single Nagios instance can put
onto the Gearman job server. Keep the Gearman job server close to the
Nagios box. Best practice is to put both on the same machine. Both
processes will utilize one core. Some testing with my workstation
(Dual Core 2.50GHz) and two worker boxes gave me these results. I used
a sample Nagios installation with 20.000 Services at a 1 minute
interval and a sample plugin which returns just a single line of
output. I got over 300 Servicechecks per second, which means you could
easily setup 100.000 services at a 5 minute interval with a single
Nagios box. The amount of worker boxes depends on your check types.
See this article about benchmarks with .
Exports export data structures from the Nagios core as JSON data. For
each configurable event one job will be created. At the moment, the
only useful event type is the logdata event which allows you to create
a json data job for every logged line. This can be very useful for
external reporting tools.
Set the queue name to create the jobs in. The return code will be sent
back to the core (Not all callbacks support return codes). Callbacks
are a list of callbacks for which you want to export json data.
export=<queue>:<returncode>:<callback>[,<callback>,...]
export=log_queue:1:NEBCALLBACK_LOG_DATA
Embedded Perl
Since 1.2.0 Mod-Gearman has builtin embedded Perl support which means
generally a big performance boost when you have lots of perl plugins.
To enable embedded Perl you need to run configure with
–enable-embedded-perl
./configure --enable-embedded-perl otheroptions...
The –with-perlcache configure option has been replace by a runtime
configure option use_perl_cache.
Not all perl plugins support EPN. You can fix them, add #
nagios: -epn in the first 10 lines of the script or set
use_embedded_perl_implicitly=off so all scripts without the explicit
tag are run without embedded Perl.
The default configuration of Mod-Gearman enables embedded Perl, but
only uses it for Perl scripts which explicitly set # nagios: +epn.
This is a very safe way of using embedded Perl but you probably miss
some plugins which do not set the header and still would run with EPN.
You may want to use the mini_epn from your Nagios installation to
verify if a plugin works with EPN or not.
General EPN documentation is valid for Mod-Gearman as well:
Mod-Gearman does not fix all of the memory leaks introduced with
Nagios and Embedded Perl, but it moves the leaks away from the core.
And they do not affect Mod-Gearman at all, as they are only in the
preforked worker processes which will be restarted automatically from
time to time (see max-jobs).
How to Monitor Job Server and Worker
Use the supplied check_gearman to monitor your worker and job server.
Worker have a own queue for status requests.
%> ./check_gearman -H <job server hostname> -q worker_<worker hostname> -t 10 -s check
check_gearman OK - localhost has 10 worker and is working on 1 jobs|worker=10 running=1 total_jobs_done=1508
This will send a test job to the given job server and the worker will
respond with some statistical data.
Job server can be monitored with:
%> ./check_gearman -H localhost -t 20
check_gearman OK - 6 jobs running and 0 jobs waiting.|check_results=0;0;1;10;100 host=0;0;9;10;100 service=0;6;9;10;100
How to Submit Passive Checks
You can use send_gearman to submit active and passive checks to a
gearman job server where they will be processed just like a finished
check would do.
%> ./send_gearman --server=<job server> --encryption=no --host="<hostname>" --service="<service>" --message="message"
How to build send_gearman.exe
After installing strawberry perl, you need to install the
PAR::Packer module and run pp:
pp -z 9 -M Class::Load::XS -M Moose -M Nagios::Passive::Base -M Params::Validate::XS -o send_gearman.exe send_gearman.pl
Or just use the prebuild one from labs.consol.de:
How to Submit check_multi Results
check_multi is a plugin which executes multiple child checks.
See more details about the feed_passive mode at:
You can pass such child checks to Nagios via the mod_gearman
neb module:
%> check_multi -f multi.cmd -r 256 | ./send_multi --server=<job server> --encryption=no --host="<hostname>" --service="<service>"
If you want to use only check_multi and no other workers, you can
achieve this with the following neb module settings:
broker_module=/usr/local/share/nagios/mod_gearman.o server=localhost encryption=no eventhandler=no hosts=no services=no hostgroups=does_not_exist config=.../module.conf
encryption is not necessary if you both run the check_multi checks
and the Nagios check_results queue on the same server.
How to Set Queue by Custom Variable
Set queue_custom_variable=worker in your Mod-Gearman NEB
configuration. Then adjust your nagios host/service configuration and
add the custom variable:
define host {
hostgroup_test
The test hostgroup does not have to exist, it is a virtual queue name
which is used by the worker.
Adjust your Mod-Gearman worker configuration and put test in the
hostgroups attribute. From then on, the worker will work on all jobs
in the hostgroup_test queue.
What About Notifications
Notifications are currently not possible to distribute via
Mod-Gearman. The Nagios core would have to be patched to support this.
And i think its not very useful at all. So don’t expect this feature
to be implemented in the near future.
Supported Dependencies
Mod-Gearman works best with libgearman/gearmand 0.33 and Nagios 3.2.3. If in
doubt, use these versions.
Lib-Gearman
Mod-Gearman has successfully been tested on the following Gearmand
Versions. It is recommended to always use the latest listed version of
libgearman.
Mod-Gearman works best since version 3.2.2 up to the latest stable Nagios 3.5.1.
Nagios 4 is not fully tested yet, but there is a preview version
available here
the nagios4 branch of the source tree.
Mod-Gearman works on the Naemon core as well with the same remarks
as Nagios 4.
To be clear, Icinga is not the recommended platform for Mod-Gearman
and not supported in any way. However, people have reported it works
with Icinga 1.2.0, 1.8 and 1.10.1 but it seems like some statistics
are not updated.
Make sure you have at least one worker for every queue. You should
monitor that (check_gearman).
Add Logfile checks for your gearmand server and mod_gearman
Make sure all gearman checks are in local groups. Gearman self
checks should not be monitored through gearman.
Checks which write directly to the Nagios command file (ex.:
check_mk) have to run on a local worker or have to be excluded by
the localservicegroups.
Keep the gearmand server close to Nagios for better performance.
If you have some checks which should not run parallel, just setup a
single worker with –max-worker=1 and they will be executed one
after another. For example for cpu intesive checks with selenium.
Make sure all your worker have the Nagios-Plugins available under
the same path. Otherwise they could’nt be found by the worker.
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