Systemd equivalent for autossh demon?

[walle]

On my Debian based servers, I use systemd to make sure my reverse SSH tunnel starts at boot and make sure it's running. Now I want to do similar to my Unraid server.

 

What is the equivalent to this file

[Unit]
Description=My AutoSSH tunnel service
After=network.target

[Service]
Environment="AUTOSSH_GATETIME=0"
ExecStart=/usr/bin/autossh -M 0 -o ServerAliveInterval=60 -o ServerAliveCountMax=3 -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -NTi /etc/ssh/id_ed25519 -R 1234:localhost:22 [email protected]

[Install]
WantedBy=multi-user.target

?

Edited April 22, 2023 by walle
Typo in codesnippet

[apandey]

/config/go.txt is a startup script for unraid, if all you want is trigger something on every boot

 

The user scripts plugin also allows you to schedule scripts at various triggers and events - like cron, array start / stop etc.

Further, what you want to do might be possible via a docker container which can be set to auto start with array

[walle]

Thank you for your rely Apandey.

 

Currently I have this bottom of the go-file:

# Autossh relay
/usr/bin/autossh -M 0 -o ServerAliveInterval=60 -o ServerAliveCountMax=3 -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -NTfi /etc/ssh/id_ed25519 -R 1234:localhost:22 [email protected]

 

The thing is autossh instance sometimes dies without any apparent reason. I have seen behavior for a few of my other servers where I have initiated autossh with a cronjob. This is quite worrisome for me sense this may be the only way I can remotely connect to the server.  The other servers I have runs autossh with systemd have worked flawlessly.

 

This is why I want to run autossh  as a service/demon or whatever else that is similar to systemd and that works even if the array haven't started. So I don't think either user scripts or Docker based solutions will not work for me.

[apandey]

If you could run it via cron, user scripts would do it for you. It has a cron trigger

 

I don't understand why docker won't work. That is the preferred way to run things on unraid

 

What is your use case for the tunnel? Maybe unraid already had a preferred way to do that

[walle]

My use case is my Unraid server is behind a CG-NAT, aka. the public IP number is shared, so it isn't possible to SSH to the server directly over the internet. The workaround I have for this is to let the server connect via a tunnel to a VPS. When I need to access my server remotely, I do a reverse tunnel connection via the VPS to my server. In other words, If the tunnel goes down, I can no longer access the server.

 

In order to keep the tunnel alive, I currently use autossh and trigger it in the GO-file. But this doesn't seem to be enough, sense I have seen autossh process die time to time. So I need some kind of solution that can monitor autossh and restart it when needed. I don't think, as far as I know, either cron or user scripts plugin can do that.

 

In regards to Docker, it's normally my go-to solution to solve most of my problems and could maybe partly solves the issue with health checks. But I don't think it's a good fit in this case for two reasons. First of all, I don't want to SSH into the container and I think there is no good way to "break out" from it in order to access the host. Second, Docker will not run unless the array have started. I need to have remote access to server even if the array goes down or the array can't start for some reason.

Edited April 24, 2023 by walle
Clerefying CG-NAT and typo.

[JonathanM]

Perhaps it would be better to build a lightweight PC based router with your tunnel and failsafes built in so your whole network is available with the proper firewall rules.

[walle]

Humm, good idea. My router is a Unifi console and maybe possible to run autossh with a demon on that. Otherwise my plan B is to run a Raspberry PI with Rasbian + autossh and use the configuration I mentioned in my first post. In case of autossh fails on my Unraid server, I can still login via the pi to the network.

[apandey]

On 4/26/2023 at 8:58 AM, JonathanM said:

Perhaps it would be better to build a lightweight PC based router with your tunnel and failsafes built in so your whole network is available with the proper firewall rules

That is what I have, pfSense with VPN server. All network security happens here and availability is not a concern due to focused application. Unraid is then just another appliance on the inside then 

[walle]

I looked into if it was possible to run autossh as a demon on my Unifi console, it seems to not be possible (without do a bunch of hacky stuff).

 

Put a Raspberry PI on the network is most likely workaround I will probably do if it can't be solved with Unraid.

Edited April 27, 2023 by walle