caddy/dist/init/linux-systemd/README.md

systemd unit for caddy

Please do not hesitate to ask if you have any questions.

Quickstart

The provided unit file assumes that you want to run caddy as www-data and group www-data, both having UID and GID 33 here. Adjust this to your liking according to the preferences of you Linux distribution!

groupadd -g 33 www-data
useradd \
  -g www-data --no-user-group \
  --home-dir /var/www --no-create-home \
  --shell /usr/sbin/nologin \
  --system --uid 33 www-data

mkdir /etc/caddy
chown -R root:www-data /etc/caddy
mkdir /etc/ssl/caddy
chown -R www-data:root /etc/ssl/caddy
chmod 0770 /etc/ssl/caddy

• Install the unit configuration file: cp caddy.service /etc/systemd/system/
• Reload the systemd daemon: systemctl daemon-reload
• Make sure to configure the service unit before starting caddy.
• Start caddy: systemctl start caddy.service
• Enable the service (automatically start on boot): systemctl enable caddy.service
• A folder .caddy will be created inside the home directory of the user that runs caddy; you can change that by providing an environment variable HOME, i.e. Environment=HOME=/var/lib/caddy will result in /var/lib/caddy/.caddy.

Configuration

• Do not edit the systemd unit file directly. Instead, use systemd's builtin tools:
  • systemctl edit caddy.service to make user-local modifications
  • systemctl edit --full caddy.service for system-wide ones
• In most cases it is enough to override the ExecStart directive.
  • systemd needs absolute paths, therefore make sure that the path to caddy is correct.
  • example:

[Service]
; an empty value clears the original (and preceding) settings
ExecStart=
ExecStart=/usr/bin/caddy -conf="/etc/caddy/myCaddy.conf" -agree -email="my@mail.address"

• To view the resulting configuration use systemctl cat caddy
• Double check permissions of your document root path. The user caddy runs as needs to have access to it. For example:

# caddy would run as        www-data:www-data
# serving, in this example: /var/www

sudo -u www-data -g www-data -s \
  ls -hlAS /var/www

Tips

• Use log stdout and errors stderr in your Caddyfile to utilize journalctl.

• journalctl is systemd's log query tool.

• Let's say you want all the log entries since the last boot, beginning from the last entry: journalctl --reverse --boot --unit caddy.service

• To follow caddy's log output: journalctl -fu caddy.service

• Send a signal to a service unit's main PID, e.g. have caddy reload its config: systemctl kill --signal=USR1 caddy.service

• If you have more files that start with caddy – like a caddy.timer, caddy.path, or caddy.socket – then it is important to append .service. Although if caddy.service is all you have, then you can just use caddy without any extension, such as in: systemctl status caddy

• You can make your other certificates and private key files accessible to a user www-data by command setfacl, if you must:

setfacl -m user:www-data:r-- /etc/ssl/private/my.key