Hi Igor,
On Wed, Jun 18, 2014 at 01:10:25PM -0700, Igor Serebryany wrote:
> Hi!
>
> I am trying to figure out what the effect of adding the `cookie` option to
> a `server` config line is. According to this chunk of documentation:
>
> https://cbonte.github.io/haproxy-dconv/configuration-1.4.html#5-cookie
>
> "This value will be checked in incoming requests, and the first
>
> operational server possessing the same value will be selected."
>
> However, doesn't this require me enabling a cookie load balancing
> algorithm?
A cookie "persistence" method, not load balancing. Cookie provides the
exception to load balancing : if a cookie is found, then no load balancing
happens and the correct server is picked instead. But you're right, you
need to set a "cookie" directive. I'm used to use this :
cookie SRV insert indirect nocache
> What I mean is, if I don't explicitly set any load balancing
> algorithm and the default (roundrobin) is chosen, it seems as though
> setting the cookie actually as no effect.
That's true. In the past we used to reject such a configuration, but
recently we relaxed the check because there was no other way to keep
the per-server cookie values when temporarily disabling cookie
persistence for debugging or whatever. So now such a configuration is
perfectly valid but the cookie is never looked up.
> In fact, setting the cookie should have no effect unless I specify
> `appsession`, `cookie`, or `balance uri` (or one of the other persistent
> `balance` algorithms) in a backend. Is that correct?
No, it's unrelated to the balancing algorithms nor to appsessions, it's
only used by the "cookie" directive.
Hoping this helps,
Willy
