[Xymon] Agent information

[J.C. Cleaver]

On Tue, January 27, 2015 10:37 pm, Sanjana Ahlawat wrote:

>
> Thanks for the prompt reply. Many of my doubts got cleared from what you
> have answered but I would be really pleased if u can provide little more
> information on the process of data collection by client. It is clear that
> xymonclient.sh collects the data and is than forwarded to the server. But
> my main query is how does this collects(xymonclient.sh) data. I have an
> understanding that message data is read from system logs or error logs,
> but what about the cpu, disk and other information.
>
> Thanks and Regard
> Sanjana
>


Sanjana,

All of those values are collected as the raw output from various unix
shell commands.

"xymonclient.sh" checks its local OS type (eg, "linux") and then executes
(eg.) "xymonclient-linux.sh". That script simply executes basic utilities
like 'free', 'df', 'top', 'ps', etc... The output is appended to the
overall "client" message being sent back to the server.

Once it's received server-side, the xymond_client process listens for
incoming "client" messages, determines that it relates to an (eg.) linux
server, and evaluates the output of those free/df/top/etc. commands,
creating status messages as appropriate to reflect whether the CPU load
average has exceeded the defined threshold.

Note that when running xymonclient.sh in "--local" mode, xymond_client
actually runs on the client machine, which then sends those status
messages up to the server. However, the basic principle is the same:
xymonclient(-*).sh executes raw *nix commands and the output is parsed by
a different tool to isolate the cpu/disk/memory statistics.


HTH,

-jc


>
>
> On Wed, Jan 28, 2015 at 8:44 AM, Jeremy Laidman <jlaidman at rebel-it.com.au>
> wrote:
>
>> Sanjana
>>
>> The apt-get tool is for Debian-based systems, including Ubuntu.  These
>> use
>> the "deb" packaging format, which is different from the "rpm" (Red Hat
>> Package Manager) format that other systems (not just Red Hat) use.
>>
>> You can list the files installed by a "deb" package using the "dpkg"
>> tool.  So the following might list the files that were installed by
>> apt-get
>> for you:
>>
>>   dpkg --listfiles xymon-client
>>
>> I don't know the name of the package that you installed, but substitute
>> as
>> appropriate.  If you don't know the package name either, running "dpkg
>> --list | grep xymon" might show you.
>>
>> The client package typically creates a client directory structure with
>> subdirectories called "bin", "etc", "ext", "tmp" and "log".  Some of
>> these
>> might be symbolic links to other directories.  You might find these all
>> under /usr/lib/hobbit/client/.
>>
>> The client package would also install a start-up or "init" script to
>> start
>> the "xymonlaunch" daemon at boot time.  In some releases of the package,
>> the init script actually runs another script called runclient.sh, and
>> this
>> in turn runs xymonlaunch. Either way, the goal is to have xymonlaunch
>> running in memory.  Once started, the xymonlaunch process runs
>> everything
>> else that's required to perform the Xymon agent tasks.
>>
>> The xymonlaunch process looks at the clientlaunch.cfg file (probably in
>> the "etc" subdirectory) and starts processes that are defined in that
>> file.  The only thing that needs to run from clientlaunch.cfg is what is
>> defined in the [client] section.  This section tells xymonlaunch to run
>> the
>> "xymonclient.sh" script every 5 minutes.
>>
>> Assuming a default "central mode" installation, the xymonclient.sh
>> script
>> has two main tasks.  The first task is to collect local client data (CPU
>> usage, disk usage, etc) for reporting to the Xymon server.  The second
>> task
>> is to fetch any (optional) configuration data from the Xymon server and
>> store it in a temporary file.  The temporary file is used to collect
>> additional client data to send to the Xymon server on the next run.
>>
>> As mentioned, the client data collection is performed by the
>> xymonclient.sh script.  One of the first things this script does it to
>> work
>> out the type of system on which it is running.  It then runs an
>> OS-specific
>> script as appropriate.  For example, on a Linux system, xymonclient.sh
>> will
>> run xymonclient-linux.sh.  The OS-specific script is where the majority
>> all
>> the data is actually collected.  It's all collated into a client message
>> format and written out for xymonclient.sh to collect and report back to
>> the
>> Xymon server.
>>
>> The client message is sent back to the Xymon server over a TCP
>> connection
>> on port 1984.  The Xymon server collects this message, parses the
>> different
>> sections for useful metrics, and uses the data to create status
>> information
>> and RRD files for graphing.  All of the status information is stored in
>> html files on disk, so that a web server, such as Apache, can display it
>> all.  Some information, such as the various graphs of performance
>> metrics,
>> is dynamic, and uses some CGI scripts to be called by the web server.
>>
>> The Xymon server also runs a xymonlaunch process, and has a similar
>> configuration file called tasks.cfg.  There's much more that goes on
>> here,
>> so there are many more processes started by the server from the
>> tasks.cfg
>> file.
>>
>> The Xymon server's different components communicate with each other via
>> various message formats.  I've mentioned a "client" message containing
>> client data.  There are other messages also, such as "status" messages
>> that
>> some the Xymon server components can report "red" or "yellow" or "green"
>> conditions.  Each message type has its own "channel" handler.  For
>> example,
>> a client message usually contains a [df] section with the output of the
>> "df" command, and this includes disk usage figures.  The xymond process
>> gives the message to the xymond_client process, which parses the [df]
>> section for disk usage levels, and if a threshold is exceeded (90% by
>> default) then xymond_client will send a "status" message over TCP port
>> 1984
>> containing the alert colour ("yellow" for 90%) and other information.
>> The
>> status message is then received by xymond which updates the "disk"
>> status
>> page for the server in question.  The xymond process also sends the
>> status
>> message to the xymond_rrd process so that it can add the disk usage
>> percentages to an RRD file for graphing.
>>
>> Xymon clients can also send message types other than "client" messages,
>> and the most common one is the "status" message that I've already
>> mentioned.  In fact, the forerunner to Xymon, called Big Brother, status
>> messages almost exclusively, and the "client" message is a much more
>> recent
>> invention.
>>
>> One of Xymon's awesome features is how extensible it is, and the
>> "status"
>> message is the classic way to extend Xymon's functionality.  The "ext"
>> subdirectory on a client is usually where extension scripts are located
>> (but they could be anywhere).  You can write a script to monitor
>> anything
>> you like, and report it to the Xymon server using a status message.
>> Such a
>> script can be as simple as:
>>
>> #!/bin/sh
>> RESULT=`sudo smartctl -H /dev/sda0 2>&1`
>> if echo "$RESULT" | grep "Status: OK"; then
>>     COL="green"
>> else
>>     COL="red"
>> fi
>> printf "status $MACHINE.smart $COL SMART status $COL\n$RESULT\n" |
>> $XYMON
>> $XYMSRV @
>>
>> You simply arrange for the script to be run every 5 minutes as an "ext"
>> script, and you'll end up with a new "smart" status page (and a
>> corresponding green, yellow or red dot on the summary page) on your
>> Xymon
>> server web interface.
>>
>> This is fairly simplistic overview, and there are many features I
>> haven't
>> mentioned, but I hope it answers some of your questions.  The official
>> introduction to Xymon is here:
>>
>> http://xymon.sourceforge.net/xymon/help/manpages/man7/xymon.7.html
>>
>> Cheers
>> Jeremy
>>
>> On 28 January 2015 at 00:09, Sanjana Ahlawat
>> <sanjana.ahlawat at gssltd.co.in
>> > wrote:
>>
>>> Hi Team
>>>
>>> I am new to xymon and trying to learn about it. But I am unable to
>>> figure
>>> out few questions.
>>>
>>> 1. I run xymon client installation by apt-get. but can you tell me what
>>> is actually running or getting installed in my system is it a rpm or
>>> what?
>>> 2. how my agent works. how does it gains information from the system it
>>> is running on.
>>> 3. what is the architecture of the xymon.
>>>
>>> I would really appreciate your help. Please give me the insight of the
>>> tool.
>>>
>>> --
>>> Thanks and Regards
>>>
>>> *Sanjana *
>>>
>>>
>>>
>>> _______________________________________________
>>> Xymon mailing list
>>> Xymon at xymon.com
>>> http://lists.xymon.com/mailman/listinfo/xymon
>>>
>>>
>>
>
>
> --
> Thanks and Regards
>
>
>
>
>
>
> *Sanjana Wily Admin Team,Gateway Software Solutions Pvt. Ltd.249(A) , 1st
> FloorEast of Kailash , Sant NagarNew Delhi-110065,
> India..sanjana.ahlawat at gssltd.co.in <sanjana.ahlawat at gssltd.co.in>*
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