HAProxy Connection Limits and Queues

blog20210129-01.cfg

global
   maxconn 60000

blog20210129-02.cfg

global
   maxconn 60000

frontend website
   maxconn 20000
   bind :80
   default_backend web_servers

frontend database
   maxconn 20000
   bind :3306
   default_backend database_servers

frontend api
   maxconn 20000
   bind :8080
   default_backend api_servers

blog20210129-03.cfg

frontend website
   maxconn 20000
   bind :80
   default_backend web_servers

backend web_servers
   balance roundrobin
   server s1 192.168.0.10:80
   server s2 192.168.0.11:80
   server s3 192.168.0.12:80

blog20210129-04.cfg

backend web_servers
   balance roundrobin
   server s1 192.168.0.10:80 maxconn 30
   server s2 192.168.0.11:80 maxconn 30
   server s3 192.168.0.12:80 maxconn 30

blog20210129-05.cfg

backend web_servers
   mode http
   balance roundrobin
   server s1 192.168.0.10:80 maxconn 30
   server s2 192.168.0.11:80 maxconn 30
   server s3 192.168.0.12:80 maxconn 30

blog20210129-06.cfg

backend web_servers
   balance roundrobin
   timeout queue 30s
   server s1 192.168.0.10:80 maxconn 30
   server s2 192.168.0.11:80 maxconn 30
   server s3 192.168.0.12:80 maxconn 30

blog20210129-07.cfg

 backend web_servers
   balance roundrobin
   acl is_checkout path_beg /checkout/
   http-request set-priority-class int(1) if is_checkout
   http-request set-priority-class int(2) if !is_checkout
   timeout queue 30s
   server s1 192.168.0.10:80 maxconn 30
   server s2 192.168.0.11:80 maxconn 30
   server s3 192.168.0.12:80 maxconn 30