Berkutman

upstream asterisk {
  server 127.0.0.1:8088;
}
server {
  ...
  location /ws {
    proxy_buffers 8 32k;
    proxy_buffer_size 64k;
    proxy_pass http://asterisk/ws;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header Host $http_host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_read_timeout 999999999;
  }
}

https://www.bidon.ca/fr/notes/asterisk-webrtc
https://wiki.asterisk.org/wiki/display/AST/Configu...
https://wiki.asterisk.org/wiki/display/AST/WebRTC+...

upstream backend {
server backend1.example.com weight=1;
server backend2.example.com:8080 weight=2;
}

server {
location / {
proxy_pass http://backend;
}
}

weight настраиват ькак душе угодно например
server backend1.example.com weight=1;
server backend2.example.com:8080 weight=5;
backend1 будет балансироваться между backend2 каждый пятый запрос

Пример кэширования, если не хочешь что либо кэшировать то proxy_cache_bypass $cookie_nocache;

proxy_cache_path /etc/nginx/cache keys_zone=cache:30m;

upstream backend {
server 127.0.0.1:8088 max_fails=4 fail_timeout=43s;
}
location / {
proxy_pass http://backend;
proxy_cache cache;
proxy_cache_valid 40s;
}
location / {
proxy_pass http://backend;
proxy_cache cache;
proxy_cache_valid 40s;
}

location ~* \.php$ {
proxy_cache_bypass $cookie_nocache;
proxy_pass http://backend;
}