Mailcow on TrueNAS

marshalleq

I read a while back about support only being on a few linux distro’s (I currently run on the supported Ubuntu version). But I got to thinking that now TrueNAS has docker support built in (and more importantly docker compose support - something that other NAS like appliances struggle with), that perhaps I should look to migrate mailcow into that. That would save me all the overhead RAM and CPU which would be nice and would probably work a lot better with ZFS caching as well.

From memory this would be an unsupported configuration, but really one of the main points of docker is that it is portable. So my question is, has anyone done this? Any tips, or opinions? Might give it a go tomorrow if no major reasons not to.

Thanks.

mlcwuser

Mailcow provides its own scripts to deploy and update the Docker stack. Would it be possible to replicate all this in TrueNAS? Maybe, but as you said yourself, it would be unsupported and undocumented, so you’d basically have to figure it all out yourself, and you’d be on your own if you ran into problems, and my gut feeling is that you almost certainly will.

So if you want to run Mailcow on a TrueNAS box, I’d strongly recommend setting up a VM and then following the instructions in the official documentation.

esackbauer

mlcwuser I’d strongly recommend setting up a VM and then following the instructions in the official documentation.

This would also be my recommendation. Mailcow needs 6 GB RAM, the RAM overhead with a basic Debian installation without desktop environment and only SSH server is minimal, you won’t notice it..

marshalleq

OK, that is something I was wondering about (the scripts side of it). So really it’s a bit of a misnomer being dockerised, as you must have a VM of a specific type which kind of negates the whole point of having docker really. I already have it running in a VM in TrueNAS. I would far prefer it to not be, but looks like there isn’t much choice.

I wonder what the reasoning is for dockerising it and then placing a dependency back on the OS. Seems highly unusual and counter intuitive.

esackbauer

marshalleq placing a dependency back on the OS. Seems highly unusual and counter intuitive.

mailcow establishes its own firewall rules via iptables to the host OS (e.g. as feedback from netfilter/fail2ban).
Many protocols are bound to ports on the host OS, and mailcow is designed to be put without additional firewall on the internet, it creates its own firewall. And this might or might not interfer with other containers or services running on the same host.
That is also the reason why you should not enable a firewall on the host OS.
mailcow is a complex solution, as every mail server/groupware server is. Its not just another docker container or stack.

mlcwuser

marshalleq I wonder what the reasoning is for dockerising it and then placing a dependency back on the OS. Seems highly unusual and counter intuitive.

I’d say the main reason is that it is easier for the Mailcow developers to maintain because they have a single source of truth within their images. And it also makes it much easier for users, e.g. OS upgrades are much easier because of Docker than they would be if all components were installed via distro packages or even third party repos.

And no, Mailcow is not really OS dependent, it runs on most major Linux distros that can run Docker, if you take care of the few things @esackbauer mentioned. But yes, Mailcow, like TrueNAS, has to be seen as an appliance rather than another Docker stack, and therefore it makes sense to run it in a dedicated VM to avoid issues, and this is even more true if you plan to run it on another appliance like TrueNAS, which is not a regular Linux distro, but only based on one.

marshalleq Yes, this is exactly my point though, docker is meant to be portable, so bare metal or otherwise.

Yeah sorry, I should have been more clear. With baremetal, I meant on a bare metal Linux installation with Docker, instead of in a VM with Docker

mlcwuser

You can toatally run Mailcow on a bare metal Linux system. But TrueNAS isn’t just Debain vith a fancy webUI, it’s an appliance.

I mean, you could probably install it directly via commandline following the Malcow docs, i.e. download the mailcow-dockerized foldder via git clone and then run the install script. The million dollar question is then what happens to the installation when you upgrade TrueNAS, and how it affects the network configuration of TrueNAS etc.

You would have to test all this extensively to avoid any nasty surprises, and even then there is no guarantee it won’t break at some point in the future. As I already said, TrueNAS, even if it is based on Debain, is more of a classic appliance, meaning they only support configurations via webUI and API. So you would be in completely unsupported territory, not only on the Mailcow side, but also on the TrueNAS side.

marshalleq

mlcwuser Yes, this is exactly my point though, docker is meant to be portable, so bare metal or otherwise.

[unknown] That explains why it doesn’t work, but not really why it was designed like that. I mean, (just for arguments sake to make the point) why not just make it a normal application that goes on top of the OS then, why dockerise it if it’s not portable). Perhaps it’s easier to keep up to date - I guess that’s one potential reason.

I hadn’t realised it was designed to be placed directly on the internet, I wonder how many people here do that. Myself I do what I think any sane person would do and put all my things behind a firewall I control. I have noticed it doesn’t play so nice like that, in particular the NGINX config when I already have another NGINX is probably more complicated as a result, certificates are a bit of a nightmare too as a result, but I have no choice but to make automated scripts and such. I’m not really sure who the target market is any more.

Either way, it is still my favourite mail server and I have set up quite a few of them in my time.

marshalleq

Yes, sounds about right. I’m getting an error on replying and I see it’s posted three times in a row above, relying to esackabauer but says he is unknown. Do you see those replies? Let’s see how this one goes.

Anyway, good to know - I like how you’re calling mailcow an appliance - that makes a lot more sense. I wish I could run it bare metal on TrueNAS though, but I can see in that philosophy why it doesn’t work. I’ve wanted a dockerised mail server for a very long time and thought I had it with this one and while it technically is dockerised, it really doesn’t feel like docker if I need an OS for it. Still, it’s a fantastic email server and I like that if I wanted to I could drop it into the cloud pretty easily, but there again, the whole OS is going to ping me for storage etc which at that point becomes not worth it for my size. I’m already an outlier though, most people don’t run their own mail servers at home!

mlcwuser

marshalleq I wish I could run it bare metal on TrueNAS though, but I can see in that philosophy why it doesn’t work.

Just to be clear, I’m not saying it’s impossible to make it work, but at least for my taste, there are far too many moving parts, especially for something as critical as email.

As for resources: If you don’t have many users, you might get away with 4GB for the full suite, now that they’ve replaced Solr with Flatcurve for full-text search, or even less if you disable full-text search and/or some of the other memory intensive components like Clam AV and Sogo, or if you don’t use Active Sync with the latter.

marshalleq

Yes agreed. I have run mine on 8GB for some time, but it was pressing the limit so have upped it to 16 now. I could probably get away with 12. I’m more concerned with disk space at the moment, the overhead of Ubuntu does actually add quite a bit, even if I am using a text only server build.

marshalleq

As a closing summary for anyone else coming here. Mailcow is an appliance, meant to be directly connected to the internet. While it may seem it should be portable because It uses docker, it actually isn’t because it isn’t published as a docker only system, but as an appliance with docker used inside it, the OS and the docker images must be used together. Disappointing and unexpected, but it is still a great email system. Hopefully one day it will be a real full fledged docker application.