[HEADS-UP] systemd for F14 - the next steps

[Simo Sorce]

On Thu, 22 Jul 2010 19:04:44 +0200
Lennart Poettering <mzerqung at 0pointer.de> wrote:

> But also HTTP is a good candidate. When apache shuts down it closes
> the listening socket but will finish processing the requests it
> already began to process. Would apache use socket actviation like
> this it would hence be restartable without loosing a single HTTP
> connection: what is already accepted will be processed, but what has
> not been accepted yet will be delayed until apache is back up again.
> 
> Something similar is of course true for every state-less protocol like
> this, where each requests can be processed independently of every
> other request.
> 
> And when a daemon crashes only the requests that were currently
> processed will be lost, all others stay queued and will then be
> deqeued and processed after the restart.
> 
> Socket activation does not prevent all kinds of data loss or denial of
> service when a daemon crashes. However it is actually big step to make
> the data loss minimal and the outage window as short as possible.

Bad example, it may make sense if you have a single host, but if you
have multiple HTTP servers, you want the one that died to stop answering
until it is back up and running and ready to server requests.

The last thing you want is to have a client wait forever because the
systemd doesn't kill the socket but apache is not able to properly
restart (say for a configuration mistake).

Simo.

-- 
Simo Sorce * Red Hat, Inc * New York