haproxy: add page (#21599)

pages/common/haproxy.md

@@ -0,0 +1,36 @@
+# haproxy
+
+> Fast and reliable HTTP reverse proxy and load balancer.
+> More information: <https://manned.org/haproxy>.
+
+- Check configuration file for validity:
+
+`haproxy -c -f {{path/to/haproxy.cfg}}`
+
+- Start HAProxy with a configuration file:
+
+`haproxy -f {{path/to/haproxy.cfg}}`
+
+- Start in daemon mode:
+
+`haproxy -D -f {{path/to/haproxy.cfg}}`
+
+- Start in master-worker mode:
+
+`haproxy -W -f {{path/to/haproxy.cfg}}`
+
+- Start with debugging mode enabled (foreground, verbose output):
+
+`haproxy -d -f {{path/to/haproxy.cfg}}`
+
+- Reload configuration with graceful shutdown of old process:
+
+`haproxy -f {{path/to/haproxy.cfg}} -sf {{pid}}`
+
+- Set maximum number of simultaneous connections:
+
+`haproxy -f {{path/to/haproxy.cfg}} -n {{maxconn}}`
+
+- Reload with zero downtime by reusing sockets from old process:
+
+`haproxy -f {{path/to/haproxy.cfg}} -x {{path/to/haproxy.sock}} -sf {{pid}}`