Master / Slave(s) patch for Cacti 0.8.7b

ldrolez · Post by **ldrolez** » Wed Feb 20, 2008 10:26 am

Hi !
Here's my simple modification to have a master / slave architecture. Just replace the original poller.php with the one below and:
1- install cacti on slave servers without the DB setup. Install the new poller.php also.
2- configure cacti to use the existing master mysql server. (and set-up mysql for remote TCP connections)
3- run 'poller.php --slave' in the cron, on slaves.
4- if a device should use a slave poller, simply add 'slave:theslavehostname' in the device's notes field.

Note that time sync between the master and the slaves is important so use NTP.

All suggestions are welcome ! Only a few dozen lines were modified for this first implementation, so it's not optimal regarding the current threads/processes launched by the poller. Anyway it works !

Ludovic.

ldrolez · Post by **ldrolez** » Wed Feb 20, 2008 11:29 am

Update: It seems to work better if the slave pollers are the last ones to run... Still investigating... (add a sleep 60 in your slave cron jobs).

ldrolez · Post by **ldrolez** » Thu Feb 21, 2008 9:16 am

Hi !

I've fixed the 'slaves must be last' bug. However, please note that the slaves should not run 'poller.php --slave', before the master, because the "poller_output" table would be cleared by the master.
So here is my crontab entry:
*/5 * * * * sleep 20;php /home/cacti-0.8.7b/poller.php --slave >/tmp/poller.log 2>&1

I've attached an updated version of poller.php and the patch fof Cacti 0.8.7b.

Cheers,

Ludo.

mia1dolfan · Post by **mia1dolfan** » Thu Mar 06, 2008 2:56 pm

Thank you for sharing your work!

I was thinking of trying your setup. My question does this setup create two sets of RRD files? If so, could I mount the rra directory as a nfs share? Do you think this would work with the boost plugin?

ldrolez · Post by **ldrolez** » Wed Mar 12, 2008 6:16 am

Hi !

The rrd files are on the 'master' Cacti server (as well as the database).

Since boost uses its own custom poller, I don't think that it would work. Anyway, my hack should also improve the performance, since polling scripts can be distributed on several hosts

Cheers,

Ludovic.

chrisgapske · Post by **chrisgapske** » Wed Mar 12, 2008 8:26 am

Can this be used in a way that you could have more than one slave ?

ldrolez · Post by **ldrolez** » Wed Mar 12, 2008 11:41 am

Yes it should work

I only tested with one slave...

BSOD2600 · Post by **BSOD2600** » Wed Mar 12, 2008 1:17 pm

1) you realize this is being talked about to be implemented in the future, right? http://forums.cacti.net/viewtopic.php?t=24869

2) Consider submitting it to http://www.cacti.net/bugs.php

cigamit · Post by **cigamit** » Sat Mar 22, 2008 9:21 pm

Also, just to note, I have basically took the same concept and made a plugin using it. You can select a poller per device using a drop down menu. New slave Pollers automatically register themselves with the master. It also doesn't require any wierd stuff like making sure the master poller runs first. Doesn't work with boost though, as it actually uses a few of the same concepts (separate poller_output table).

I'm still working on a few minor things, but overall seems to work just fine.

super-hornet · Post by **super-hornet** » Mon Jun 16, 2008 1:29 am

Hi cigamit

Is your plugin ready? I would like to test it on my side. Thinking of putting the slave on different country instead

SH

cigamit · Post by **cigamit** » Sun Sep 07, 2008 11:41 am

Nope. There are some fundamental issues in Cacti that stop it from going prime time. Once I resolve those issues then I will release it.

SoftDux · Post by **SoftDux** » Wed Sep 10, 2008 4:06 pm

Just out of curiosity, cigamit - what needs to change in Cacti for your script to work?

Post by **TheWitness** » Fri Sep 12, 2008 6:25 am

I'm trying to free up some of my rare personal time these days, evident by my absence on the forums, to remove the fundamental issues that prevent us from doing the remote pollers.

I have given this topic so much thought, I need to do the development, so I can make some room in my brain for other things

TheWitness

Post by **gandalf** » Fri Sep 12, 2008 2:37 pm

TheWitness wrote:I have given this topic so much thought, I need to do the development, so I can make some room in my brain for other things

I recommend Dumbledore's pensieve to ease this task

Reinhard

Frizz · Post by **Frizz** » Fri Sep 12, 2008 4:39 pm

TheWitness wrote:I'm trying to free up some of my rare personal time these days, evident by my absence on the forums, to remove the fundamental issues that prevent us from doing the remote pollers.

I have given this topic so much thought, I need to do the development, so I can make some room in my brain for other things

TheWitness

Take all the time you need, to achieve this milestone in the Cacti architecture.
Let's have a talk about your ideas at the 3.CCC.eu (via Skype) at the 11.october 2008.
We're all very curious.
regards
-Frizz

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Master / Slave(s) patch for Cacti 0.8.7b

Master / Slave(s) patch for Cacti 0.8.7b

Updated poller.php

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