Hello Sébastien,
On Mon, 15 Oct 2018 at 16:40, Sébastien Kurtzemann <s...@seize.tv> wrote: >> No. Only *restart* closes existing front and backend connections. >> Reload (both seamless and regular) closes them gracefully, so no >> request is lost. > > > Okay. I think I confound connections and servers sessions... :( > Are sessions purged after a seamless reload ? > > So is there a way to keep sessions states or to configure haproxy TCP > backends to not send a request to a server that is currently handling a > connection ? When haproxy reloads, and your backend server is configured with maxconn 1 on haproxy: - the old process will keep 1 connection open to your server, until all old requests are served (so connections close and the process exits) - the new process will open the 1 connection when the first request comes in So there is a moment when both old and new process are running, where there are actually 2 connections to your backend server (one from the old haproxy process, one from the new process). If you don't want that, you cannot reload, you must restart instead. This will kill the existing session immediately, only allowing for the new connection. There is no way to keep the same TCP session alive across haproxy reloads or restarts. The old connection must go away and a new connection must be opened. When you restart, this happens sequentially, when you reload it's the opposite. Seamless reload makes it possible for haproxy to pass *LISTENING* (but not established) sockets from the old to the new process, so that we don't loose any new incoming connections on the frontend while reloading. Existing connections and transaction however are still handled by the old process, until it can close them. Lukas
