How to set environment variables for n8n running in Proxmox

I setup a HomeLab last year running Proxmox and have been having fun running a variety of different workloads on it. This weekend I decided I wanted to get a local community instance of n8n running locally to test it out.

Now when setting up the various LXC Containers that are running my different workloads, I’ve been relying on the excellent Community Scripts repository, originally created by tteck. There was a script to install the community edition of n8n, so I had it up and running pretty quickly…. once I had to connect to some external services though I soon ran into an issue.

I don’t expose any of my LXC’s to the outside world, for obvious reasons, but I do use some fake internal DNS values to make my applications easy to access via Nginx Proxy Manager. Now when I went to connect n8n to Google to test out some different data flows, the Callback URL being generated from n8n was always using the localhost domain, which wasn’t correct in my scenario.

Some quick googling on this told me that I needed to set the WEBHOOK_URL environment variable in my docker-compose to change it. I wasn’t using Docker though, so this led me down a rabbit hole of how to set these env vars for an n8n instance running directly in Debian.

To cut a long story short, and to save anyone else who run into this issue. I found the issue on a GitHub issue for the previous version of the Community Scripts when they were still maintained by tteck.

It turns out you need to modify the n8n.service definition to have the environment variables read by n8n when it loads. This can be found at /etc/systemd/system/n8n.service. You then need to add a new line for each env var that you want to add, in my case it now looks like this:

[Unit]
Description=n8n

[Service]
Type=simple
Environment="N8N_SECURE_COOKIE=false"
ExecStart=n8n start
Environment="WEBHOOK_URL=<<DOMAIN_FOR_N8N>>"
[Install]
WantedBy=multi-user.target

After setting the variable and rebooting the LXC I was back in business!