почему если поставить worker_processes больше 1 , Ngix перестает обращаться к Apache ?

worker_processes 1;

pid logs/nginx.pid;
events {
worker_connections 1024;
}


http {
include mime.types;
default_type application/octet-stream;

log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';

access_log logs/access.log main;

sendfile off;
tcp_nopush on;
tcp_nodelay on;

#keepalive_timeout 0;
keepalive_timeout 65;

#gzip on;

server {
listen 80;
server_name .site2.ru ;

access_log logs/host.site2.log main;

# Main location
location / {
proxy_pass http://127.0.0.2:8080/;
proxy_redirect off;

proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

client_max_body_size 10m;
client_body_buffer_size 2m;

proxy_connect_timeout 90;
proxy_send_timeout 90;
proxy_read_timeout 90;

proxy_buffer_size 4k;
proxy_buffers 4 512k;
proxy_busy_buffers_size 1m;
proxy_temp_file_write_size 1m;
}
}

server {
listen 80;
server_name .site3.ru;

access_log logs/host.site3.log main;

# Main location
location / {
proxy_pass http://127.0.0.3:8080/;
proxy_redirect off;

proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

client_max_body_size 10m;
client_body_buffer_size 2m;

proxy_connect_timeout 90;
proxy_send_timeout 90;
proxy_read_timeout 90;

proxy_buffer_size 4k;
proxy_buffers 4 512k;
proxy_busy_buffers_size 1m;
proxy_temp_file_write_size 1m;
}
}

server {
listen 80;
server_name .site4.ru;

access_log logs/host.access_site4.log main;

# Main location
location / {
proxy_pass http://127.0.0.4:8080/;
proxy_redirect off;

proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

client_max_body_size 10m;
client_body_buffer_size 2m;

proxy_connect_timeout 90;
proxy_send_timeout 90;
proxy_read_timeout 90;

proxy_buffer_size 4k;
proxy_buffers 4 512k;
proxy_busy_buffers_size 1m;
proxy_temp_file_write_size 1m;
}
}