Fixng Nginx 502 Gateway Timeout with proxy_pass During Deployments

The article mentions nginx returning 502 when a backend is down during a deploy. This a problem in the cases where restarting the backend isn't atomic.

If the backend is able to perform a "reload" (vs. a slower stop/start or restart) and/or replace the old instances with the new when they're up -- assuming that's an atomic operation -- nginx will not return a 502.

If one is rapidly iterating and prefers having a somewhat cleaner stop/start, the advice can be helpful even though it masks/papers over a problem (the backend being down).

To me the most appropriate way (when not dealing with kubernetes, but rather just vms) is to be able to mark specific server to not receive any new requests, wait for the requests to stop coming in and then deploy.

IIS web server has this but not nginx :(

Detecting a failure and minimizing the request wreck that it causes is different from handling a deploy. The second one should cause no wrecks because your deploy management system should be able to tell your proxy layer to drain the target of deploy to allow the deploy to proceed when a target has no traffic

I've never had this problem when doing reverse proxies through nginx. Theres no delay when I restart node, the 502 goes away right after.

Envoy is the new hotness in proxyland.

Is this "fixing"? The proper fix would be to use a seamless deployment by either spawning a new vm with new version, then redirecting the traffic once it's ready. Or by doing the same with a new version of the app server on the same host and replacing the socket when ready.

Otherwise, the requests will potentially wait a long time to be handled while the app starts up.