On Wed, Aug 8, 2018 at 11:09 PM, Willy Tarreau <[email protected]> wrote: > Hi Baptiste, > > On Wed, Aug 08, 2018 at 08:14:31PM +0200, Baptiste wrote: > > Hi Willy, > > > > Could you please also backport those patches to 1.8? > > Actually, 1.8 broke a haproxy's default behavior (when multiple servers > > shares the same hostname) and that this patch helps fixing. > > > > here is the commit: 8e2d9430c0562ed74276d7f58e92706c384c0a36 > > As you know usually we don't backport features (been burnt too much in > 1.5), but here if it fixes a regression, I guess it's a bit different. > I've had a new look at the code and it looks safe. > > However could you please explain a bit more what exactly changed and > how this broke, so that we can add the explanation in the backport > commit message ? It's important because if anyone later faces an issue, > we'll have to decide if we need to keep it or to revert, and in this > case to know what it's supposed to fix. > > Until HAProxy 1.7, the DNS resolver was able to allocate the same IP address to all (or a portion of) servers sharing the same hostname and being in the same backend. This behavior annoyed the people who wants to scale based on DNS response, hence we introduced prevention of duplication of IP addresses for servers sharing the same hostname and being in the same backend. So we fixed it in 1.8 with no possibility no "disable" this behavior. There are still some use cases where people may want to use the same IP address for multiple servers (they are running several instances of the same application on a server but on different ports, they use the same dev server several times in the backend, etc...).
So this patch doesn't change default behavior introduced in 1.8 while allowing to change it when required. Baptiste
