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
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
