Synology SNMP Network Monitoring with LibreNMS Docker

Tutorial for installing LibreNMS on Synology NAS via Docker to monitor SNMP enabled network devices

Update - 07 Oct, 2023

Changelog

• Working LibreNMS tag for tutorial up till 23.5.0-1
• Adjust LibreNMS docker command to use 23.5.0-1

Versions

LibreNMS - 23.5.0 - Fri May 19 2023 23:32:19 GMT+0800
MariaDB Docker Container - 11.0.2-MariaDB-1:11.0.2+maria~ubu2204
Synology DSM - DSM 7.1.1-42962 Update 5

Users contributed to the update: miknl

Step by Step

It can be time-consuming to google the web & forums for a straight-forward answer, especially IT related, where the replies you get either expect you to understand the acronyms/terms and just point you in a "vague" direction

As with all tutorials, I can't possibly cover all aspects, but one thing for sure, you will learn to "learn", if possible in layman easy to understand terms and finally give you a stable and working setup/environment example in the end

Some disclaimer: I am not a network/tech specialist. Tutorials written on my website all came from my personal experience, so it will suit the enthusiasts that want to learn more about networking without browsing multiple forums and to learn from practical

Requirements

The whole idea started when I bought the Synology 916+, so I will base the setup on installing in Syno NASes

• Main Requirement & Setup (This tutorial)
  • Synology NAS model able to run the following:
    • Package: Docker
    • DSM SSH access
  • Optional: Other SNMP enabled devices like Routers, Managed Switches, Workstations to list a few
• My Devices
  • Synology DS916+
  • OSX - MacBook Pro
• What you will touch on
  • DSM SSH access
  • Terminal/Putty
  • Docker

Who is this tutorial for

• Beginners & Enthusiasts
  • Next to no experience in Linux but willing to be adventurous
• SMB Owners, Managers, Entrepreneurs who want to understand or DIY deploy their own NMS monitoring for company devices
• Home lab owners
• Linux veterans; why are you here?! ;)

Install Docker, Enable SSH & SNMP

Install Docker

Install the Docker app from DSM Package Center >> Search for "Docker"

This should be pretty straightforward

Enable SSH

Well, if you don't know how to SSH into your DSM. Let's begin by enabling SSH option in your Synology

Control Panel (Advanced Mode) >> Terminal & SNMP >> Check ☑️ Enable SSH service port: 22 (default 22, change if you wish accordingly)

Enable SNMP

Click on the SNMP tab
Check ☑️ Enable SNMP service
Check ☑️ SNMPv1, SNMPv2c service

Community: enter-something-here

Enter in the Community field a rather difficult but not too complex phrase, which the NMS will ask you for later. The default is "public" on most SNMP devices, and is highly recommended to change it to something unique

Do not use your frequently used password as it will be seen on the DSM SNMP settings page

SNMP Device Information Device Name: fill-in accordingly, usually NAS hostname
Device Location: optional* fill-in accordingly, a vague location will do
Contact: Email optional* useful for sending alerts from NMS, can also be changed in LibreNMS later

SSH into Syno NAS

Skip to next section if you already know this ;)

For Windows Users; please Google on how to SSH into your NAS using PowerShell putty

OSX Users

Open "Terminal" from your Mac and type in the following commands:

ssh user-with-admin-rights@your-nas-ip

If this is your first time, you should see a warning and be asking whether you would like to add the fingerprint, choose Yes by entering 'yes'

Enter your password and you should be greeted with the following output (With power comes great responsibility!)

Proceed to gain root access by typing

sudo -i

Enter password again and you will have root access. Now... let the fun begin!

Save your commands!!

At this point of time, it is highly recommended to save any/all docker run commands for the following reasons

1. Test run of docker run commands
2. Readability, ease of editing and substitute your values
3. Docker container/image update IMPORTANT
   1. Docker by itself doesn't update the image as it's built that way. You can google and find many answers on this
   2. Go to Page 2 for Upgrading steps

Testing Purposes

Beginners

Beginners following this tutorial should just copy/paste the commands that I've posted on this page as is to minimise any errors/conflict due to existing configurations, typos or if you are not very fluent in Linux

Get it to work in a testing environment first, then recreate the changes accordingly like passwords, mounts and your own customizations to secure your install further before using it for production (long-term, real-use)

Veterans / Homelabbers

I am currently using a distributed poller whereby my DigitalOcean droplet hosts the main LibreNMS poller and connected via OpenVPN to the local subnet pollers that I am currently monitoring

If you want to take it further by using a reverse proxy like nginx or traefik, this tutorial does not cover that. I don't intend to put LibreNMS behind a reverse proxy, as it complicates security with public-facing subdomain and configuration. Although recently I started experimenting with nginx... ... for now I'm KISSing it :)

MariaDB Setup & Install

Prepare MariaDB Docker folders

By default, Synology docker should create a new shared folder for your docker container data. The default should be at /volume1/docker

Navigate to your docker folder

cd /volume1/docker

Next, create MariaDB folder

mkdir mariadb

Install MariaDB container

Let's pull/download the latest MariaDB image by running the command below

docker pull mariadb:latest

Update accordingly to your /volumeX/ path. Eg: /volume2/docker/mariadb if you have a different parent volume, or to a path that you prefer to use

docker run \
-v /volume1/docker/mariadb:/var/lib/mysql \
-e MYSQL_ROOT_PASSWORD='root_password' \
-e TZ=Asia/Singapore \
--name mariadb \
-d \
--restart always \
mariadb:latest \
--innodb_file_per_table=1 \
--lower_case_table_names=0

** Outputs on my screenshots will be different from what was posted as I already have a running LibreNMS container on my Syno NAS. Note: I am using mariadb-test and librenms-test, with port 8669 instead of 8668 for screenshots **

MariaDB Docker Details/Explanation

-v /volume1/docker/mariadb:/var/lib/mysql

Save persistent MariaDB database data onto our newly created mariadb folder under /volume1/docker

-e MYSQL_ROOT_PASSWORD='root_password'

Replace SQL root_password with a generated password if you wish, as we won't be using this often

-e TZ=Asia/Singapore

Replace timezone settings with your preferred timezone TZ Timezone List

--name mariadb

We name the container as "mariadb". Without this, Docker will randomly pick a name for your container

-d

Run the container in daemon/background

--restart always

Always restart the container. This docker container will restart itself if you were to reboot your Synology NAS. More options @ Docker's documentation

mariadb:latest

Use the latest mariadb image

--innodb_file_per_table=1
--lower_case_table_names=0

Run MariaDB with options as per official LibreNMS documentation

\

Indicates a newline, which makes it easier to read, you can also docker run commands without the newline, the above command will look like this one-liner without \:

docker run -v /volume1/docker/mariadb:/var/lib/mysql -e MYSQL_ROOT_PASSWORD='root_password' -e TZ=Asia/Singapore --name mariadb -d mariadb:latest --innodb_file_per_table=1 --lower_case_table_names=0

Setup MariaDB LibreNMS Database and User

Now that MariaDB has been installed, time to configure the database for use with LibreNMS

Before we proceed, please run the following to make sure that your database is ready to accept commands

docker logs -f mariadb

MariaDB container is still setting up your database

2023-06-25 15:06:54 0 [Warning] mariadbd: io_uring_queue_init() failed with ENOSYS: check seccomp filters, and the kernel version (newer than 5.1 required)
2023-06-25 15:06:54 0 [Warning] InnoDB: liburing disabled: falling back to innodb_use_native_aio=OFF

If you see the above, just wait for a few moments, the container will restart itself multiple times

Ready

When is it ready, you will see the similar output of the following:

2023-06-25 15:08:42 0 [Note] Server socket created on IP: '0.0.0.0'.
2023-06-25 15:08:42 0 [Note] Server socket created on IP: '::'.
2023-06-25 15:08:42 0 [Note] InnoDB: Buffer pool(s) load completed at 230625 15:08:42
2023-06-25 15:08:43 0 [Note] mariadbd: ready for connections.
Version: '11.0.2-MariaDB-1:11.0.2+maria~ubu2204'  socket: '/run/mysqld/mysqld.sock'  port: 3306  mariadb.org binary distribution

Since our database is ready, press Ctrl+C to end the logs session

Setup Permissions

Run the following command to log in to the SQL Console

docker exec -it mariadb mariadb -u root -p

Next, we will create a user for LibreNMS to use to read/write to MariaDB. We will create a user called librenms

Change 'libre_password' to your preferred password

CREATE DATABASE librenms CHARACTER SET utf8 COLLATE utf8_unicode_ci;
CREATE USER 'librenms'@'%' IDENTIFIED BY 'libre_password';
CREATE USER 'librenms'@'localhost' IDENTIFIED BY 'libre_password';
GRANT ALL PRIVILEGES ON librenms.* TO 'librenms'@'%';
FLUSH PRIVILEGES;
exit

Now that MariaDB has been configured, issue a restart to the MariaDB container

docker restart mariadb

LibreNMS Setup & Install

Prepare LibreNMS Docker folders

Same deal, just different names :)

cd /volume1/docker
mkdir librenms
cd librenms
mkdir logs
mkdir rrd
touch custom.config.php

We created librenms folder, in it folder logs, rrd and custom.config.php file to be used by LibreNMS for any custom configuration

Generate an App Key

First, as per jarischaefer's instructions, we will generate an APP_KEY value to be used for our docker run command

Run the following to generate a base64 key

docker run --rm jarischaefer/docker-librenms generate_key

Copy/Save the base64 key, as we will need it to configure our LibreNMS container variables

Install LibreNMS Container

We are using jarischaefer/docker-librenms's container for this tutorial

If you've followed this tutorial before Jul, 23 2020, breaking change is to NOT use "db" as the hostname alias to link back to MariaDB container. Latest tutorial uses "libredb" as the hostname alias

Replace accordingly, mainly BASE_URL, APP_KEY and TZ

docker run \
-p 8668:80 \
-e DB_HOST=libredb \
-e DB_NAME=librenms \
-e DB_USER=librenms \
-e DB_PASS='libre_password' \
-e APP_KEY=base64:THE_GENERATED_KEY_ABOVE \
-e BASE_URL=http://YOUR_NAS_IP:8668 \
-e TZ=Asia/Singapore \
--link mariadb:libredb \
-v /volume1/docker/librenms/logs:/opt/librenms/logs \
-v /volume1/docker/librenms/rrd:/opt/librenms/rrd \
-v /volume1/docker/librenms/custom.config.php:/opt/librenms/conf.d/custom.config.php:ro \
--name librenms \
-d \
--restart always \
jarischaefer/docker-librenms:23.5.0-1

LibreNMS Docker Details/Explanation

-p 8668:80

Expose port 8668 which will be bound to the container's port 80

You can ignore this for now if you don't know what that means, head over to Page 2's Synology & Docker Network 101 Section to understand more later

-e DB_X=

DB_X values point to your MariaDB container created above, substitute them with the correct values

-e APP_KEY=base64:THE_GENERATED_KEY_ABOVE

Paste in the generated key from the initial docker run command, includes 'base64:'

-e BASE_URL=http://YOUR_NAS_IP:8668

Replace YOUR_NAS_IP with your Synology/Server IP address

-v /volume1/docker/librenms/custom.config.php:/opt/librenms/conf.d/custom.config.php:ro \

We mapped the file custom.config.php and set it with :ro "read only". This means that Docker only has read permissions to the file and will not be able to make changes to it

--link mariadb:libredb

We are assigning a hostname alias of 'libredb' to the container named 'mariadb' which we have just created above. DB_HOST is then set to libredb

Examples

--link your-existing-container-name:hostname-alias

Configure LibreNMS Database & User Creation

Preparing LibreNMS Database

Now that MariaDB and LibreNMS containers have been set up and ready, let's instruct LibreNMS container to prepare (more like the ol' Setup/Install?) the Database for use

Run the following command

docker exec librenms setup_database

The terminal will not show any progress, wait for the process to complete, which takes around 1~5mins (SSD~HDD)

If you run into the following error:

Could not connect to database, check logs/librenms.log.

Wait for a few moments and try again

Admin User Creation

Run the following command to add an admin to LibreNMS

docker exec librenms create_admin

We are almost done!

Login to LibreNMS by going to the following address in your browser:

http://YOUR_NAS_IP:8668

Log in with the following:

Username: admin
Password: admin

Add your Synology & Other Devices

Synology Device

Proceed to add your Synology NAS to LibreNMS for monitoring

Before we add your Synology device, let's find its IP when accessing from Docker

Run the following in Synology Terminal/Console (not the Container's bash)

docker inspect bridge | grep 'Gateway'

Most installs return 172.17.x.x, there are cases which you might have a different subnet like 172.18.x.x

On the menu of LibreNMS, Devices >> Add Device

Substitute your above IP as the Hostname for the Device to add to LibreNMS for monitoring

Hostname: 172.17.0.1
SNMP Version: v2c
Community: your-snmp-passphrase-created-above

LibreNMS will tell you that it has been successfully added

Not being updated

As LibreNMS runs polling on a cron/schedule, you may not see your newly added Synology updated on the page.

To manually "Discover" your device and force the UI to update:

Go to the top menu "Devices" >> "Device Dependencies"

You should see your newly added Synology named as "172.17.0.1" or your Docker gateway

Click on the Device IP to show device information

Once you are in the Device page, proceed to click on the vertical-triple-dots, and then select "Capture"

Under "Discovery" tab, click "Run" and you should see the discovery poller at work

Once it has stopped, you may proceed to click on "Devices" >> "Device Dependencies"

After the page is loaded, hover over the menu and it should be updated to "All Devices" >> "Storage"

Congratulations!

You have a working NMS collecting and monitoring your SNMP enabled devices!

Adding Other Devices

Proceed to add other SNMP enabled devices with their IP address as the hostname

Make sure the Device's SNMP protocol version is correct, v1 or v2c when adding devices!

Wait for around 5~10mins for it to collect data and it will output your graphs

Ongoing Updates depends on you

Let me know in the comments if this tutorial helped or, especially if it didn't!

You can reach me @ Contact

Continue to Page 2. Troubleshooting

(Post) Setup / Optional(s)
Useful Commands
Networking issues
Troubleshooting
Synology & Docker Network 101
Updating Containers
After Care & Upgrade Errors