问题
I am having varnish 4 server working with nginx as reverse proxy connected to ELB.
Every 2 days or so my server is stop responding and I see 499 responses in nginx access.log
restarting nginx is solving the problem.
Why am I started to get these 499 responses?
Why restarting nginx solving the issue?
回答1:
I solved my issue after understanding two facts:
1) ELB instance has dynamic DNS name
2) nginx resolve DNS names only on reload/restart
The problem was that the ELB changed its IP address and nginx kept the old IP address.
The solution is to use resolver in nginx.conf. Here is my nginx.conf:
http {
resolver x.x.x.x valid=30s;
}
server {
set $elb "example.com";
location / {
proxy_pass http://$elb;
}
}
The resolver IP address should be a DNS server such in /etc/resolv.conf.
来源：https://stackoverflow.com/questions/40200938/varnish-nginx-elb-499-responses