LibreNMS upgrade PHP from 7.2 to 7.4 – CentOS 7

First you’ll need to install the remi repo

sudo wget
sudo wget
rpm -Uvh remi-release-7.rpm epel-release-latest-7.noarch.rpm

You’ll need to install yum-utils, disable all old php versions, and enable the remi-php74

sudo yum install -y yum-utils
sudo yum-config-manager --disable remi-php56
sudo yum-config-manager --disable remi-php71
sudo yum-config-manager --disable remi-php72
sudo yum-config-manager --disable remi-php73
sudo yum-config-manager --enable remi-php74

If you run into issues you may want to see if you have the webtatic repo installed. I had to disable it to get php to update.

vi /etc/yum.repos.d/webtatic
name=Webtatic Repository EL7 - $basearch
enabled=0   <- Disabled by changing to a 0

And running the yum update should update it to php 7.4

sudo yum update

More information available here.

LibreNMS update to Python 3

You may get the following alert in LibreNMS. Basically you need to install python 3 to keep things up to date.

Python 3 is required to run LibreNMS as of May, 2020. You need to install Python 3 to continue to receive updates. If you do not install Python 3 and required packages, LibreNMS will continue to function but stop receiving bug fixes and updates.

Install Python 3

Install Python 3 with yum, or apt if you are on a Debian based distro.

sudo yum install python3
sudo pip3 install -r /opt/librenms/requirements.txt

Verify LibreNMS is updated and working

Run the following commands to make sure that LibreNMS is working correctly and is up to date.

cd /opt/librenms
sudo ./validate.php
sudo ./

LibreNMS backup script

You should be able to copy and paste the following in a file and then execute from cron. Should work out of the box, but you can change the backup directory and the path if needed/wanted.


# LibreNMS backup script
# Jan 1, 2019

lDate=`date +%Y%m%d-%H%M`       # local date + hour minute
dDate=`date +%Y%m%d`            # todays date

# If you have the script, you can trigger a backup notification
ALERT="/home/admin/ -b"

# Directory to backup to

# MySQL settings for tar and sqldump

# Directory that contains data

# tar LibreNMS dir
# tar SQL dir "the whole thing with the innode files
# sql dump of the db for extra redundancy

if [ -d ${bDir} ]; then
echo "backup dir exist, starting to backup"
        echo "backup dir not available.  Quiting"
        exit 1

${ALERT} "Starting backup for ${bName} - `date`"

systemctl stop mariadb httpd
# LibreNMS data backup
tar -zcvf ${bDir}/${lDate}-${bName}.tgz ${dDir}
if [ $? -eq 0 ]; then
        echo "Tar succesfully backed up ${bDir}"
        echo "Tar failed while trying to backup ${dDir}"
        echo " ${lDate} - Tar failed while trying to backup ${dDir}" >> ${LOG}
        ${ALERT} "${lDate} - Tar failed while trying to backup ${dDir}"

# MySQL data backup
tar -zcvf ${bDir}/${lDate}-${bName}-mysql.tgz ${sqlDir}
if [ $? -eq 0 ]; then
        echo "Tar succesfully backed up ${sqlDir}"
        echo "Tar failed while trying to backup ${sqlDir}"
        echo " ${lDate} - Tar failed while trying to backup ${sqlDir}" >> ${LOG}
        ${ALERT} "${lDate} - Tar failed while trying to backup ${sqlDir}"

systemctl start mariadb httpd
sleep 5

 # SQL dump
mysqldump -u ${sqlUN} -p'4rfvBHU8!' ${sqlDB} > ${bDir}/${lDate}-${bName}.sql
if [ $? -eq 0 ]; then
        echo "MySQL DB dumped"
        echo "Ran into error while doing sql dump"
        echo "${lDate} - Ran into error while doing sql dump" >> ${LOG}
        ${ALERT} "${lDate} - Ran into error while doing sql dump"

echo "Removing old backups"
if ( ls ${bDir} | grep -q ${dDate} );then
        find ${bDir}/* -prune -mtime +31 -exec rm {} \;
        echo "Looks like there are no backup files!  Aborting!!!"
        ${ALERT} "${lDate} - Error: find failed to find any backup files in backup dir.  Aborting!!!"

${ALERT} "Finished backup for ${bName} - `date`"

LibreNMS ./ – Some folders have incorrect file permissions, this may cause issues.

Helpful article here.

When running the following command,

sudo /opt/librenms/

I’ve been getting the following errors.

[FAIL]  Some folders have incorrect file permissions, this may cause issues.
    sudo chown -R librenms:librenms /opt/librenms
    sudo setfacl -d -m g::rwx /opt/librenms/rrd /opt/librenms/logs /opt/librenms/bootstrap/cache/ /opt/librenms/storage/
    sudo chmod -R ug=rwX /opt/librenms/rrd /opt/librenms/logs /opt/librenms/bootstrap/cache/ /opt/librenms/storage/

You can run the commands and fix the problem, but they pop up later and it does the same thing.

Create Script to fix permissions

Work around is to have a script run these commands every few minutes.

vi /root/

Add the following

sudo chown -R librenms:librenms /opt/librenms 
sudo setfacl -d -m g::rwx /opt/librenms/rrd /opt/librenms/logs /opt/librenms/bootstrap/cache/ /opt/librenms/storage/ 
sudo chmod -R ug=rwX /opt/librenms/rrd /opt/librenms/logs /opt/librenms/bootstrap/cache/ /opt/librenms/storage/

Make the script executable

sudo chmod +x

Add to Crontab

sudo crontab -e 

Add the following entry to Cron to run every 30 minutes

*/30 * * * * /root/

LibreNMS – failed

All the following commands are run from the “/opt/librenms” directory

$ sudo ./ 
Re-running /opt/librenms/ as librenms user
Updating to latest codebase                        FAIL
error: Your local changes to the following files would be overwritten by merge:
Please, commit your changes or stash them before you can merge.

Checking with validate.php shows that you can run githup-remove to fix it

$ sudo ./validate.php
[WARN]  Your install is over 24 hours out of date, last update: Mon, 23 Feb 2020 05:43:12 +0000
         Make sure your cron is running and run ./ by hand to see if there are any errors.
 [WARN]  Your local git contains modified files, this could prevent automatic updates.
         You can fix this with ./scripts/github-remove
         Modified Files:

Run “sudo ./scripts/github-remove -d”

$ sudo ./scripts/github-remove -d
Are you sure you want to delete all modified and untracked files? [y/N] y

You should also be able to remove the files individually if the above command does not work.

Run validate again to make sure it checks out good.

Now run ./

LibreNMS – Setting up Alerts to monitor Voltage on Mikrotik Routers

Create Alert Rule

Go to “Alerts -> Alert Rules” Then “Create rule from Collection”

Search for “Sensor under limit” and Select

Setup Sensor under limit

Configure Alert Rule

Add another rule to limit to just the Voltage Sensors by using the “sensors.sensor_class = Voltage”

Select your Groups and Transports and Save.

Modify Alert Rule

Disable Alerts for Unused Ports

You may get some alerts because there are some ports that do not have any any voltage on them. You can disable them on a per device basis by going to the “device -> Edit -> Health” and turning alerts off

Turn off voltage alerts on port that has no PoE

Manually create graph of device in LibreNMS

In LibreNMS, you can hit the “Show RRD Command” to give you the command to manually create a graph.  Copy the command.

In the command below, the path shows the IP address of the device to generate the graph from.  Theoretically you can change that to a different IP to generate graphs from other devices.

SSH into server server and run the command, change /tmp/randomtext to something like /root/mikrotik_092619.png or whatever you want.  You can also adjust the size, color etc of the graph.

 rrdtool graph /tmp/randomtext --alt-y-grid --alt-autoscale-max --rigid -E --start 1515946500 --end 1516551300 --width 1712.7 --height 483 -c BACK#EEEEEE00 -c SHADEA
#EEEEEE00 -c SHADEB#EEEEEE00 -c FONT#000000 -c CANVAS#FFFFFF00 -c GRID#a5a5a5 -c MGRID#FF9999 -c FRAME#5e5e5e -c ARROW#5e5e5e -R normal --font LEGEND:8:DejaVuSansMono --font AXIS:7:DejaVuSansMono -
-font-render-mode normal COMMENT:'Volts Cur Min Max\n' DEF:sensor495=/opt/librenms/rrd/ LINE1:sensor495#CC0000:'Voltage 0
 ' GPRINT:sensor495:LAST:%5.1lfV GPRINT:sensor495:MIN:%5.1lfV GPRINT:sensor495:MAX:%5.1lfV\l