Running Caddy as a daemon on Ubuntu

These instructions work for me on Ubuntu 16.04.3. YMMV.

First, install Caddy by running curl https://getcaddy.com | bash -s personal hook.service,http.realip,tls.dns.cloudflare. If you don’t trust them (and you shouldn’t!), wget the script first and inspect it before running.

Next, add a user for Caddy: useradd -r -s /usr/sbin/nologin caddy. Then, add a place to store config: mkdir /etc/caddy && chown caddy:caddy /etc/caddy. Finally, give Caddy a logfile: touch /var/log/caddy.log && chown caddy:caddy /var/log/caddy.log

Caddyfile

Fire up your favorite editor (ahem, vi, ahem…) and create /etc/caddy/Caddyfile. Place the following into it:

your.fqdn.com

log /var/log/caddy.log

proxy / https://127.0.0.1:8443 { # change this to the port (and protocol) your service is running on
        websocket
        insecure_skip_verify # necessary if your proxy target is using a self-signed cert
        transparent
}
tls {
        dns cloudflare # if you use Cloudflare DNS like me, it'll automatically take care of the Let's Encrypt stuff, even if it's internal facing. Neat!
}

Systemd unit file

This goes in /lib/systemd/system/caddy.service:

[Unit]
Description=Caddy reverse proxy
ConditionFileIsExecutable=/usr/local/bin/caddy
After=network-online.target
Wants=network-online.target

[Service]
StartLimitInterval=5
StartLimitBurst=10

# command to run to start
ExecStart=/usr/local/bin/caddy -conf=/etc/caddy/Caddyfile -email=<[email protected]> -root=/var/tmp -agree=true -log stdout

# user and group to run as, must exist
User=caddy
Group=caddy

# set environment variables (for https)
Environment=CLOUDFLARE_EMAIL=<[email protected]>
Environment=CLOUDFLARE_API_KEY=<your-cloudflare-api-key>
Environment=CADDYPATH=/etc/caddy

Restart=always
RestartSec=120

[Install]
WantedBy=multi-user.target

Run systemctl daemon-reload to get Systemd to recognize the new file. Then, let it start on boot with systemctl enable caddy.service. Finally, you can fire it up with systemctl start caddy.service

Enjoy automagic https!