Configuration details:

HAPrpxy configuration file: / etc/haproxy/haproxy.cfg
It consists of two parts: global and proxies.

1. global: global configuration segment

Process and security configuration-related parameters
 Performance tuning related parameters
 Debug parameter

1. proxies: Proxy configuration segment with multiple subsegments

defaults provides default configuration for frontend, backend, listen
 listen has both front-end and back-end configurations

# Not commonly used below
 frontend front end, equivalent to server {} in nginx
 Backend backend, equivalent to upstream {} in nginx

global configuration parameters:

Official Document: https://cbonte.github.io/haproxy-dconv/2.0/intro.html

global

    #Lock the Running Directory
    chroot  /usr/local/haproxy 

    #Define global syslog servers; up to two can be defined
    log 127.0.0.1 local3 info 

    #Specify the pid file path
    pidfile /var/run/haproxy.pid

    #Running as a daemon
    deamon  

    #Maximum number of concurrent connections per haproxy process
    maxconn 4000

    #User Identity Running haproxy
    user haproxy
    group haproxy
    #perhaps
    uid 99
    gid 99
    /********************Options******************************************/
    #Number of haproxy processes open, consistent with CPU
    nbproc 4
    #CPU binding
    cpu-map 1 0
    cpu-map 2 1
    cpu-map 3 2
    cpu-map 4 3

    #Specifies the number of threads open for each haproxy process, defaulting to one thread per process
    nbthread 1

    #Socket file 1, permission of mode file, level level level, use when processing multi-process, bind socket file
    stats socket /var/lib/haproxy/haproxy.sock1 mode 600 level admin process 1
    #socket file 2
    stats socket /var/lib/haproxy/haproxy.sock2 mode 600 level admin process 2

    #Maximum number of connections per ssl for each haproxy process,Be used for haproxy In scenarios where certificates are configured
    maxsslconn 

    #Maximum number of connections per process created per second
    maxconnrate 200

    #Back-end server status check is randomly advanced or delayed percentage time, recommendation2-5(20%-50%)Between
    spread-checks 3

defaults configuration:

Provide default configuration for frontend, backend, listen

defaults
    #Default type of work
    mode http 
    #Define logs, global represents global definitions
    log  global 

    #Open session with client
    option http-keep-alive 
    #Pass-through client real IP to back-end web server
    option forwardfor 

    #When the server Id corresponds to the server hangs up, force the server to be directed to other healthy servers
    option redispatch 
    #Automatically terminate links that have been processed by the current queue for a long time when the server load is high
    option abortonclose 

    #Maximum connection waiting time for client requests to back-end server (before TCP)
    timeout connect 120s 
    #Timeout time-out of client requests to back-end server (after TCP)
    timeout server 600s 
    #Maximum inactivity time with client
    timeout client 600s 

    #session sessions are timed out and forwarded to the same back-end server in scope
    timeout http-keep-alive 120s 
    #Detection timeout for back-end servers
    timeout check 5s 

listen:

Replace the configuration of frontend and backend with listen:

listen WEB_PORT_80
    bind 192.168.7.102:80
    mode http
    balance <algorithm>
    option forwardfor
    server web1 192.168.7.101:80 check inter 3000 fall 3 rise 5
    server web2 192.168.7.101:80 check inter 3000 fall 3 rise 5

frontend configuration

Front end, equivalent to server {} in nginx

#Specify HAProxy's listening address to listen on multiple IP or ports at the same time
bind [<address>]:<port_range> [, ...] [param*]
 

frontend WEB_PORT
    bind :80,:8080
    bind 192.168.7.102:10080,:8801-8810,192.168.7.101:9001-9010
    mode http/tcp #Specify load protocol type
    use_backend backend_name #The name of the back-end server group invoked

backend configuration

Define a set of back-end servers that will be called from content.

#Specify load protocol type
mode http/tcp 
#configuration option
option 
#Define the back-end real server
server <name> <ip:port>
    #The default is 1, and the maximum value is 256, 0, which means not participating in load balancing.
    weight 
    #Mark the back-end server as a backup state
    backup 
    #Mark the back-end server as unavailable
    disabled 
    #Temporarily redirect requests to other URL s, only for http mode
    redirect prefix http://www.magedu.net/ 
    #Maximum number of concurrent connections for back-end server s
    maxconn <maxconn>
    #Backup queue length after server's connection number reaches the upper limit
    backlog <backlog>
    #Check the health status of the specified real, which is not turned on by default
    check 
        #Designable health monitoring IP
        addr IP 
        #Designated health monitoring port
        port num 
        #Health check interval, default 2000 ms
        inter num 
        #Back-end server failure checks, default 3
        fall num 
        #Back-end server restores checks from offline by default of 2
        rise num 

frontend+backend configuration example:

frontend WEB_PORT_80
    bind 192.168.7.248:80
    mode http
    use_backend web_prot_http_nodes

backend web_prot_http_nodes
    mode http
    option forwardfor
    server 192.168.7.101 192.168.7.101:8080 check inter 3000 fall 3 rise 5
    server 192.168.7.102 192.168.7.102:8080 check inter 3000 fall 3 rise 5