NEMS Linux – Nagios Enterprise Monitoring Server for Raspberry Pi 3

NEMS Linux – Nagios Enterprise Monitoring Server for Raspberry Pi

Current Version: 1.3 (November 7, 2017)
Next Major Release: 1.4 (May 8, 2018)

NEMS is a modern pre-configured, customized and ready-to-deploy Nagios Core image designed to run on the Raspberry Pi 3 micro computer. At its core it is a lightweight Debian Stretch deployment optimized for performance, reliability and ease of use.

NEMS is free to download, deploy, and use. Its development however is supported by its community of users. Please consider contributing if you can.

Please Note: NEMS is a very ambitious project, and I’m just one guy. Please consider throwing a little gift in my Tip Jar if you find NEMS saves you time or money. Thanks!

[NEMS Documentation]
[NEMS Community Forum]
[NEMS User Comments]


NEMS 1.1 Featured on Category5 Technology TV


If you like NEMS, please donate:

The Out-Of-The-Box NEMS Experience:

Buy The Needed Hardware

Raspberry Pi 3 Nagios ServerRaspberry Pi 3 are very affordable, and using our Micro SD image, you simply buy the device, “burn” the image to the Micro SD card, and boot it up.

Here’s our link to buy the device you’ll need, complete with the Micro SD card, a power adapter, a good solid case, and more:

Please buy it through that link, or let me know if you need a customized link to a different model. We get a small percentage of the sale, and it helps to make it possible to offer this as a free download.

Who Creates NEMS:
Robbie Ferguson is the host of Category5 Technology TV. He’s the kind of guy who when he figures stuff out, he likes to share it with others. That’s part of what makes his show so popular, but also what makes NEMS possible.

Support What I Do:
This project is a part of something much bigger than itself, and we’re all volunteers. Please see our Patreon page for information about our network.
– Please support us by simply purchasing your Raspberry Pi at
– We have some support links on the NEMS menu, such as buying from Amazon using our partner link. Please use these every time you use those stores. A small percentage of your purchase will go toward our projects.
– Your donations are VERY MUCH appreciated – – Please consider how many hours (and hours) of work this project has saved you, and how much you’ll save on hardware and even electrical costs as you consider contributing
– Our network also has a Patreon page – Please consider becoming a patron –

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450 Comments on "NEMS Linux – Nagios Enterprise Monitoring Server for Raspberry Pi 3"

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Hi Robbie, I get the same messages here. I was running 1.2.3 for a couple weeks, backed up configs, created a new sd with NEMS 1.3 and walked throug the nems-init side, no errors. I can access the MOTD page and can log in into Nagios but any attempt to go into config ends with SSL errors. Can i help more to track this issue?


I have the same problem as Dave. I cannot access NEMS 1.3 with Chrome, Edge or IE. I have had NEMS installed before but this is a new install with new IP.


I cannot access the System settings tool, SSL config was filled out completely. Is it possible to disable SSL for the page somehow?


I wanted to try out NEMS, so I got myself a Kingston 64GB micro SDXC card and installed the image on it.
After booting I ran top and saw that the cpu load average was over 8. This slowly decreased and after a day(!) it was down to 1.8. The system behaved extremely sluggish when I ran nems-init. The web interface was almost unusable.
I had another 8GB card lying around and installed NEMS on that one. The system worked flawlessly with that card (cpu load around 0.2).
So I wonder if the rpi and NEMS can cope with large SD cards?
Is there anything I can check to find out what is going on?



Thanks so much for this open source project! I haven’t spent much time with it yet, but I do have a lot of experience with nagios and system administrator and am looking forward to getting my hands dirty with this. Here is some initial feedback I have from my first 24 hours with NEMS:
1) PLEASE include a configuration step in the documentation or add it to the nems-init script, an option to set the locale / keyboard. After I set my passwords, I couldn’t login from my workstation to anything (nconf, webmin, ssh, etc.) except for nagvis (obviously because that password isn’t set during nems-init), but I could login to the pi using a directly connected keyboard. Come to find out, the locale/keyboard is set to GB! Not a big deal, so long as you give the option to change it during setup is all. I didn’t even think to check that at first.
2) Alllll of the login pages except for webmin are over http. Please change everything to be using https by default and have any http requests redirected to https (using mod_rewrite, as an example). It doesn’t matter if people need to generate their own certificates afterwards or maybe you could even have “let’s encrypt” be a part of the configuration process. Logins shouldn’t happen over http *ever*, even if it’s on your local network.
3) Please change the line in your nems-init script where you’re using htpasswd to add the switch “-B”. By not specifying the algorithm, you are allowing the default of MD5 to be used, which is insecure.

That’s all for now. Thanks again!


How can I change the call NEMS.local to a DynDNS name, so that I can access the web front end from remote ?
Thx in advacne for your help and your great support.


Hey Robbie,

Sorry but how do i go about monitoring another RaspberryPi on the network with NEMS?
I googled and installed SNMP on RaspberryPi but the advanced services like CPU Load , / Disk Space , Uptime SNMP
do not work 🙁

Nick Arellano

I’ve never used Nagios for monitoring before, of all the tools bundled in NEMS, how much of it is accessible with a REST api?

Nick Arellano

Is there any information about how many hosts or clients that NEMS is designed to manage?


I have several different vlans on my network. I setup NEMS on my 10.10.60.x server vlan and I can’t access it from my 10.10.50.x workstation vlan. If I start a ping from my workstation to my NEMS server it will reply once eth0 enables for about 5 ping then it starts dropping. Is there a internal firewall that I need to disable on the system so all my networks can talk to it?


Really think we need a forum and/or wiki…

Anyways, I used Webmin to set static IPs, IPv4 and IPv6 addresses.. They don’t take…

Mind you I had this same issue on Raspbian, I was hoping I didn’t with NEMS.. What am I missing?


Here’s how i resolved the ‘secondary eth0’ concern…

Using PuTTY, I ran the ‘ip -4 addr show dev eth0 | grep inet’ command and it initially displayed…

@NEMS:~# ip -4 addr show dev eth0 | grep inet
inet brd scope global eth0
inet brd scope global secondary eth0

Afterwhich I ran the ‘sudo nano /etc/network/interfaces’ command and COMMENTed out all STATIC IP Interface references.

# auto eth0
# iface eth0 inet static
# address
# netmask
# gateway

… then SAVEd that file, and proceeded to do a ‘sudo nano /etc/dhcpcd.conf’ and add the entries at the bottom of that file…

interface eth0
static routers=

… then SAVEd the file, ran a ‘sudo shutdown -r now’.

When NEMS rebooted, I re-ran the ‘ip -4 addr show dev eth0 | grep inet’ command from PuTTY once more, and it then displayed, minus the ‘secondary eth0’ reference …

@NEMS:~# ip -4 addr show dev eth0 | grep inet
inet brd scope global eth0

The reference material used to come to this conclusion was…

… and


How can I check a non standard port using check_http?


I was wondering how to remove a service from a host when it inherits from its hostgroup?


hi everyone i installed Nems on RPI3 and i want to create wifi access point by using hostapd and dnsmasq but it doesn’t work.
any idea plz ?


I’ve overcome 4 dead or limped up sd cards and am fully upgraded to 1.2.2
All modules functional
I had an error when initially using Check_MK. There is a pending user change that needs to be activated. When i try, i get errno 2 and the change continues to pend. By manually starting mkeventd | service mkeventd start | changes are processed and all is good, but it has to be manually started after every reboot
How do I get mkeventd to automatically start at boot?