Dynamically create Backend section in HAProxy configuration - proxy

Question

I have a use case where i need to use HAProxy as a proxy rather than a loadbalancer. So in my case i need many backend sections that need to be updated in the config when proxy is started.
But is there a way , where i can create new backend section dynamically ?
global
log stdout format raw daemon
stats socket ipv4#127.0.0.1:9999 level admin
stats socket /var/run/hapee-lb.sock mode 666 level admin
stats timeout 2m
defaults
log global
timeout client 50s
timeout client-fin 50s
timeout connect 5s
timeout server 10s
timeout tunnel 50s
frontend tcp-0_0_0_0-443
bind 135.27.110.163:443
mode tcp
tcp-request inspect-delay 5s
tcp-request content accept if { req_ssl_hello_type 1 }
use_backend %[req.ssl_sni,regsub(.com,.com443,g),lower,map_dom(/usr/local/etc/sample.map,bk_default)]
default_backend example_com_be
frontend tcp-0_0_0_0-5061
bind 135.27.110.163:5061
mode tcp
tcp-request inspect-delay 5s
tcp-request content accept if { req_ssl_hello_type 1 }
use_backend %[req.ssl_sni,regsub(.com,.com5061,g),lower,map_dom(/usr/local/etc/sample.map,bk_default)]
default_backend absanity_5061
backend example_com_be
mode tcp
server name1 x.x.x.x:443
backend absanity_5061
mode tcp
server name1 y.y.y.y:5061
AM using Runtime API using Socat for updating maps. But assume i was to insert a new backend section with new server details in config .. how can we achieve that ?

Answer 1

I don't think you can create new backends at runtime with the socket API. This article gives a good overview of what you can modify at runtime: https://www.haproxy.com/blog/dynamic-configuration-haproxy-runtime-api/.
However, you can add new backends without using the socket API by creating a new config with the new backends and reloading HAProxy. This article gives a good overview of how to reload HAProxy without losing connections:
https://www.haproxy.com/blog/truly-seamless-reloads-with-haproxy-no-more-hacks/