Nagios Support Forum

Hi !!!

We've a problem, when we restart nagios after a minutes if we put:
- # ps aux | grep nagios

We can appreciate some instances of nagios, and this makes strange behavior
- /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg

Why it appear some instances and not only 1 ??? We run ndoutils (v1.4) and nagios

Thanks and happy new year

yo are likely seeing parent and child processes.

Nagios will fork itself to execute the checks...

So, it's normal to fork processes ??

Because sometimes when the nagios proces forks, the controls of nagios doesn't execute or change the state and after a moment change another time

So, it's normal to fork processes ??

Yes, this is how all parent->child processes work in Unix. Nagios forks itself to run the check, event handler, or notification command, and when it's complete the child process is closed off and control is returned to the parent.

Because sometimes when the nagios proces forks, the controls of nagios doesn't execute or change the state and after a moment change another time

I'm not sure I understand what you mean. Can you explain a bit more or give an example of what you see happening on your system? There may be an issue on your system, but I don't think it has anything to do with the forks unless you somehow have multiple parent processes.

morabanc wrote:So, it's normal to fork processes ??

yes, but if you run a you should see that that all are children of a parent.

nagios 16122 1 0 Jan07 ? 00:05:36 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
nagios 32122 16122 0 Jan07 ? 00:00:00 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
nagios 32123 16122 0 Jan07 ? 00:00:00 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
nagios 32124 16122 0 Jan07 ? 00:00:00 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg

Now i execute the command "ps -ef | grep nagios" and this is the result

nagios 6539 1 0 Jan08 ? 00:00:00 ndo2db -c /usr/local/nagios/etc/ndo2db.cfg
nagios 6854 6539 0 Jan08 ? 00:03:30 ndo2db -c /usr/local/nagios/etc/ndo2db.cfg
nagios 6855 1 0 Jan08 ? 00:10:01 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
nagios 29176 1 0 12:00 ? 00:00:00 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg

As you can see there are 2 parent process of nagios.

After a moment i execute another time and then it appear OK

nagios 6539 1 0 Jan08 ? 00:00:00 ndo2db -c /usr/local/nagios/etc/ndo2db.cfg
nagios 6854 6539 0 Jan08 ? 00:03:30 ndo2db -c /usr/local/nagios/etc/ndo2db.cfg
nagios 6855 1 0 Jan08 ? 00:10:01 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
nagios 29894 6855 0 12:03 ? 00:00:00 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg

The last time I execute the command ....

nagios 6539 1 0 Jan08 ? 00:00:00 ndo2db -c /usr/local/nagios/etc/ndo2db.cfg
nagios 6854 6539 0 Jan08 ? 00:03:30 ndo2db -c /usr/local/nagios/etc/ndo2db.cfg
nagios 6855 1 0 Jan08 ? 00:10:03 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg

Until now Nagios kill the processes but the first time i execute I don't know why execute 2 independent processes.

I think this is a problem and when we feel anomal work in Nagios is because this last process doesn't kill it and always run 2 process and for that Nagios doesn't work OK. The solution is kill (kill -9 ...nagios...) every nagios process and start it another time (/etc/init.d/nagios start).

Thanks !!!!

morabanc wrote:nagios 6539 1 0 Jan08 ? 00:00:00 ndo2db -c /usr/local/nagios/etc/ndo2db.cfg
nagios 6854 6539 0 Jan08 ? 00:03:30 ndo2db -c /usr/local/nagios/etc/ndo2db.cfg
nagios 6855 1 0 Jan08 ? 00:10:01 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg
nagios 29894 6855 0 12:03 ? 00:00:00 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg

you are correct, this isn't normal

morabanc wrote:The solution is kill (kill -9 ...nagios...) every nagios process and start it another time (/etc/init.d/nagios start).

This is what I would have recommended.

Yes, I know this is the solution of the problem, but what's the solution to avoid this problem ??

What version of Nagios XI and Nagios Core are you on? This was a bug older versions of XI, but has since been resolved.

The only other thing that I know can reproduce this regularly is if you have a user outside of the nagios group try to restart the Nagios process.