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Inter server communication monitoring
Posted: Mon Jun 20, 2016 3:31 am
by sify_nagios
Hi Team,
I would like to monitor whether port 443 is listening between the Server A and Server B.
If i would configure 443 TCP port check from Nagios, it would be Server C checking port availability with Server B.
Instead of that i would like to know whether port communication between Two servers are fine or not.
Note : Requirement comes in cross platform (Linux, Windows)
Please let me know if my requirement is not clear.
Rgds
Srini
Re: Inter server communication monitoring
Posted: Mon Jun 20, 2016 9:19 am
by rkennedy
You can use check_by_ssh or check_nrpe to execute check_http on either Server A or Server B, which would then check the reciprocal.
This document is for monitoring by SSH -
https://assets.nagios.com/downloads/nag ... ng_SSH.pdf
See this one for using NRPE -
https://assets.nagios.com/downloads/nag ... g_NRPE.pdf
Here's the file that contains the current check_http from Nagios plugins 2.1.1. You'll still need to compile it. -
http://www.nagios-plugins.org/download/ ... 1.1.tar.gz
Re: Inter server communication monitoring
Posted: Mon Jun 20, 2016 9:47 am
by sify_nagios
Sorry i may not be clear to you. I don't wanna monitor the port availability from nagios.
Consider below scenario.
APP SERVER in my infra is SERVER A.
DB SERVER = SERVER B.
Nagios server called SERVER C.
From SERVER C i wanna poll either SERVER A or SERVER B to identified port(22 or 23) communication between SERVER A and SERVER B is happening or not.
Hope i am clear to you this time.
Note : Port numbers are only example. We may check different ports.
Kindly guide us to achieve above.
Rgds
Srini
Re: Inter server communication monitoring
Posted: Mon Jun 20, 2016 11:58 am
by rkennedy
Got it, you'll still need to use an agent such as NRPE or check_by_ssh so the same links apply.
As for checking the connection, if you run netstat -an on SERVER A or SERVER B, will it show the connection as established?
You should be able to use this plugin I wrote to accomplish checking the established ports.
https://raw.githubusercontent.com/rckna ... netstat.sh
Code: Select all
[root@localhost libexec]# netstat -an | grep :22
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 64 192.168.4.179:22 192.168.5.47:50684 ESTABLISHED
tcp 0 0 192.168.4.179:22 192.168.5.47:64061 ESTABLISHED
tcp6 0 0 :::22 :::* LISTEN
[root@localhost libexec]# netstat -an | grep :22 | grep 'ESTABLISHED'
tcp 0 64 192.168.4.179:22 192.168.5.47:50684 ESTABLISHED
tcp 0 0 192.168.4.179:22 192.168.5.47:64061 ESTABLISHED
[root@localhost libexec]# netstat -an | grep :22 | grep 'ESTABLISHED' | wc -l
2
The plugin as is, doesn't care if they are established or not. So you'll need to modify line 49 to this -
Code: Select all
count=$($netstat -an | grep :$port | grep 'ESTABLISHED' | wc -l)
Re: Inter server communication monitoring
Posted: Fri Jun 24, 2016 10:21 am
by sify_nagios
Hi Team,
Achieved the same by writing two lines of simple code.
Works simple and efficient.
Attached file and steps for same (to newbies like me
)
Steps:
*************************
Step 1 : Place the file in the below mentioned path of client server(SERVER_A).
/usr/local/nagios/libexec
Note : Please make sure the file has nagios user to execute permission.
Step 2 : Please append the below command in the respective config file.
File path : /usr/local/nagios/etc/nrpe/common.cfg
command[check_net]=/usr/local/nagios/libexec/check_net.sh $ARG1$
Step 3 : Now check from nagios server by following command.
/usr/local/nagios/libexec/check_nrpe -h SERVER_A -c check_ntp -p PORT_NUMBER -d SERVER_B
***************************
Thanks for your support.
Rgds
Srini
Re: Inter server communication monitoring
Posted: Fri Jun 24, 2016 11:55 am
by lmiltchev
@sify_nagios Thanks for sharing! Is it all right if we lock this thread?