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).
On Tue, Apr 13, 2021 at 6:25 AM Willy Tarreau <w...@1wt.eu> wrote: > On Tue, Apr 13, 2021 at 01:31:12AM +0000, Rmrf99 wrote: > > In this Slack engineering blog post: > https://slack.engineering/migrating-millions-of-concurrent-websockets-to-envoy/ > > > > they replace HAProxy with Envoy for **Hot Restart**, just curious does > > HAProxy new version will have similar approach? or have better > solution(in > > the future). > > So in fact it's not for hot restarts, since we've supported that even > before envoy was born, it's in order to introduce new servers at run > time. We do have some ongoing work on this, and some significant parts > are already available with experimental support: > > https://github.com/haproxy/haproxy/issues/1136 > > Willy > >
