Identity

Unit: haproxy.service
Config: /etc/haproxy/haproxy.cfg
Stats socket: /run/haproxy/admin.sock
Logs: journalctl -u haproxy, /var/log/haproxy.log (requires rsyslog; see Pain Points)
User/group: haproxy (both Debian/Ubuntu and RHEL/Fedora)
Distro install: apt install haproxy / dnf install haproxy

Key Operations

Operation	Command
Status	`systemctl status haproxy`
Graceful reload (no dropped connections)	`sudo systemctl reload haproxy` or `haproxy -sf $(cat /run/haproxy.pid) -f /etc/haproxy/haproxy.cfg`
Validate config	`sudo haproxy -c -f /etc/haproxy/haproxy.cfg`
Restart (drops connections)	`sudo systemctl restart haproxy`
Show process info via socket	`echo "show info" \| sudo socat stdio /run/haproxy/admin.sock`
Show all backends	`echo "show backend" \| sudo socat stdio /run/haproxy/admin.sock`
Show server state	`echo "show servers state" \| sudo socat stdio /run/haproxy/admin.sock`