Multiport graph widget does not work with empty data

Tags: #<Tag:0x00007fd897266c78> #<Tag:0x00007fd897266a48> #<Tag:0x00007fd897266908>

When adding a port that has no previous data collected (standby port in a HA firewall setup) to a multiport graph widget, the graph is not drawn at all and the RRDtool outputs a message “ERROR: absolute path names not allowed when talking to a remote daemon”.

Generating graphs seems to be working fine when all ports have some traffic. Single port graphs work even without any data, they just draw nothing.

Validate:

Component Version
LibreNMS 1.69-69-g0a7586b9f
DB Schema 2020_10_12_095504_mempools_add_oids (191)
PHP 7.4.3
Python 3.8.5
MySQL 10.3.25-MariaDB-0ubuntu0.20.04.1
RRDTool 1.7.2
SNMP NET-SNMP 5.8
OpenSSL

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

[OK] Composer Version: 2.0.8
[OK] Dependencies up-to-date.
[OK] Database connection successful
[OK] Database schema correct
[INFO] Detected Python Wrapper
[OK] Connection to memcached is ok
[WARN] Global lnms shortcut not installed. lnms command must be run with full path
[FIX]:
sudo ln -s /opt/librenms/lnms /usr/local/bin/lnms
[WARN] Bash completion not installed. lnms command tab completion unavailable.
[FIX]:
sudo cp /opt/librenms/misc/lnms-completion.bash /etc/bash_completion.d/
[WARN] Your install is over 24 hours out of date, last update: Tue, 01 Dec 2020 07:45:53 +0000
[FIX]:
Make sure your daily.sh cron is running and run ./daily.sh by hand to see if there are any errors.

Weird, in my setup the RRDcached was on the same server as the web-server. Using unix-socket instead of tcp-socket in config.php seems to have solved this issue.