Thanks Chris, Willy! this make me clear now. Glad to see dynamically add/remove servers feature under development.
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ On Wednesday, April 14, 2021 1:19 AM, Christopher Faulet <[email protected]> wrote: > Le 13/04/2021 à 18:15, John Lauro a écrit : > > > Sounds like the biggest part of hot restarts is the cost of leaving the old > > process running as they have a lot of long running TCP connections, and if > > you > > do a lot of restarts the memory requirements build up. Not much of an > > issue for > > short lived http requests (although it would be nice if keep alive wasn't > > followed on the old haproxy processes so they could die quicker). > > Well, AFAIK, Envoy handles hot restarts exactly the same way HAProxy does. The > old process tries to finish to process in-flight requests. The connections are > not kept-alive. The old process closes all idle connections. But it must still > wait the responses for already started requests. Both Envoy and HAProxy do it > this way. Note there is an option to kill the old process after a given time. > > The article is a bit biased and inaccurate because it suggests HAproxy does > not > support hot restarts while Envoy do it. In fact, The real difference here is > the > ability to dynamically add or remove servers with Envoy. Thanks to this > feature, > most of time, there is no reason to restart it. Thus, hot restarts are not an > issue anymore. On HAProxy side, as Willy said, this feature is under > development. > > ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ > > Christopher Faulet
