Distributed Poller RRD Cache is not working

[sus_madel]

Hi,
I have configured rrdcache on the servers with the webui. I have 5 other brand new distributed pollers. Although the rrdcache on the first server seems to be working the other 5 pollers are showing an error that they can not connect.

I followed the default steps here for Centos 7 https://docs.librenms.org/Extensions/RRDCached/

with sudo systemctl status rrdcached.service I can see that the service is started. The trouble is using netstat -an | grep 42217 I don’t see rrdcached listening on port 44217.

How can I troubleshoot this issue?

Validate.php from the distributed poller:
./validate.php

Component	Version
LibreNMS	1.51-14-g554e22d
DB Schema	2019_02_10_220000_add_dates_to_fdb (390)
PHP	7.2.16
MySQL	5.7.14-8-log
RRDTool	1.7.1
SNMP	NET-SNMP 5.7.2

====================================

[OK] Composer Version: 1.8.5
[OK] Dependencies up-to-date.
[OK] Database connection successful
[OK] Database schema correct
[FAIL] Cannot connect to rrdcached instance

config.php running on the remote pollers:
$config[‘rrdcached’] = “X.X.X.X:42217”;

The status of the service:
sudo systemctl status rrdcached
● rrdcached.service - Data caching daemon for rrdtool
Loaded: loaded (/etc/systemd/system/rrdcached.service; enabled; vendor preset: disabled)
Active: active (running) since Fri 2019-05-10 08:25:27 CDT; 2min 31s ago
Process: 167588 ExecStart=/usr/bin/rrdcached -w 1800 -z 1800 -f 3600 -s librenms -U librenms -G librenms -B -R -j /var/tmp -l unix:/run/rrdcached.sock -t 4 -F -b /opt/librenms/rrd/ (code=exited, status=0/SUCCESS)
Main PID: 167589 (rrdcached)
CGroup: /system.slice/rrdcached.service
└─167589 /usr/bin/rrdcached -w 1800 -z 1800 -f 3600 -s librenms -U lib…

Validation from the box running the rrdcache service
./validate.php

Component	Version
LibreNMS	1.51-13-g6e76f1d
DB Schema	2019_02_10_220000_add_dates_to_fdb (390)
PHP	7.2.16
MySQL	5.7.14-8-log
RRDTool	1.7.1
SNMP	NET-SNMP 5.7.2

====================================

[OK] Composer Version: 1.8.5
[OK] Dependencies up-to-date.
[OK] Database connection successful
[OK] Database schema correct

config.php on the box running rrdcached
$config[‘rrdcached’] = “X.X.X.X:42217”;
$config[‘rrdcached’] = “unix:/run/rrdcached.sock”;

[TheGreatDoc]

@sus_madel

with sudo systemctl status rrdcached.service I can see that the service is started. The trouble is using netstat -an | grep 42217 I don’t see rrdcached listening on port 443.

I guess that 443 is just a misstype and you actually mean 42217.

But, your issue is that you are running rrdcached only listening on socket.

Read Scaling LibreNMS - LibreNMS Docs and adapt to your needs/OS.

[sus_madel]

Thanks. I ended up modifying etc/systemd/system/rrdcached.service to look like instead of what was in the instructions so it would listen on port 42217.
ExecStart=/usr/bin/rrdcached -w 1800 -z 1800 -f 3600 -s librenms -U librenms -G librenms -B -R -j /var/tmp -l X.X.X.X:42217 -t 4 -F -b /opt/librenms/rrd/

Then I did a sudo systemctl daemon-reload and sudo systemctl restart rrdcached.service.

And then I changed config.php to only list:
$config[‘rrdcached’] = X.X.X.X:42217";

And I removed this:
$config[‘rrdcached’] = “unix:/run/rrdcached.sock”

This seems to now be working.
Thanks again for all the help.

[Jeff_Deng]

Hi sus_madel,

It is very good to see you updated your answer to your ticket. Please give me your recommendation if you can.

I have one LibreNMS Central Server (web + database + rrdcached), and one remote poller

The server OS are: Centos 7, rrdtool = 1.7.1

I have followed your instruction to configure etc/systemd/system/rrdcached.service. Now I can see port 42217 on the Central Server:

[root@NETQ-LibreNMS01 librenms]# netstat -an | grep 42217
tcp 0 0 192.168.100.62:42217 0.0.0.0:* LISTEN

Also I have configured: /etc/default/rrdcached

---

[Unit]
Description=Data caching daemon for rrdtool
After=network.service

[Service]
Type=forking
PIDFile=/run/rrdcached.pid
ExecStart=/usr/bin/rrdcached -w 1800 -z 1800 -f 3600 -s librenms -U librenms -G librenms -B -R -j /var/tmp -l unix:/run/rrdcached.sock -t 4 -F -b /opt/librenms/rrd/

[Install]
WantedBy=default.target

---

But my devices are still showing Error Drawing Graph from remote poller. (devices from local poller are working fine). Can you please give me an advice?

Thanks

Jeff Deng

[TheGreatDoc]

Hi Jeff,

Did you configured in your remote poller the correct rrdcached instance?

[Elias]

Can you telnet to that port from the remote poller? Just to see if it’s a network issue or something else.

[Jeff_Deng]

Thanks

I missed some some setting in /etc/default/rrdcachedthanks, it has been resolved now.

Rrdcached remote functionality

Component Version LibreNMS 1.46-40-g8bddfe722 DB Schema 273 PHP 7.2.10-0ubuntu0.18.04.1 MySQL 10.1.34-MariaDB-0ubuntu0.18.04.1 RRDTool 1.7.0 SNMP NET-SNMP 5.7.3 hello , according to “Setting up RRDCached” article rrdcached supports creating rrd files over rrdcached. i did every single step on “Distributed Poller” article but i could not manage get rrd graphs running. it always gives me “error drawing graph” error. if i choose/add nfs server-client method to my servers eve…