Willy / Simon, I think I've got a bit confused myself -
I've just installed the patches and tested and it fixes the issues we seeing with HAProxy getting stuck in DRAIN mode when the agent temporarily responds with 0% idle. i.e. when the load on the server decreases HAProxy should automatically start passing traffic again. It would however probably make sense to keep the current behaviour of having a 0 weight highlighted in blue. (but not having the DRAIN state activated) I think it is potentially important to know that the DRAIN state or AGENT DRAIN STATE is different to just weight=0 and UP. I'm happy with any colours basically as long as just setting 0 weight from the agent doesn't force agent drain. Does that make any sense? And sorry if I have caused even more confusion! On 9 April 2015 at 12:42, Willy Tarreau <w...@1wt.eu> wrote: > Hi Simon! > > On Thu, Apr 09, 2015 at 03:47:13PM +0900, Simon Horman wrote: >> There are some similarities between a weight of zero and the >> administratively set drain state: both allow existing connections >> to continue while not accepting any new ones. >> >> However, when reporting a server state generally a distinction is made >> between state=UP,weight=0 and state=DRAIN,weight=*. This patch makes >> stats reporting consistent in this regard. > > Just to be sure, doesn't it undo what the two following patches tried to > do : > > commit cc8bb92f32128a603d4206f066e99944e4049681 > Author: Geoff Bucar <viralb...@gmail.com> > Date: Thu Apr 18 13:53:16 2013 -0700 > > MINOR: stats: show soft-stopped servers in different color > > A "soft-stopped" server (weight 0) can be missed easily in the > webinterface. Fix this by using a specific class (and color). > > and : > > commit 6b7764a983a7dd97af6a5398da40c63353698328 > Author: Willy Tarreau <w...@1wt.eu> > Date: Wed Dec 4 00:43:21 2013 +0100 > > MINOR: stats: remove some confusion between the DRAIN state and NOLB > > We now have to report 2 conflicting information on the stats page : > - NOLB = server which returns 404 and stops load balancing ; > - DRAIN = server with a weight forced to zero > > The DRAIN state was previously detected from eweight==0 and represented in > blue so that a temporarily disabled server was noticed. This was done by > commit cc8bb92 (MINOR: stats: show soft-stopped servers in different > color). > This choice suffered from a small defect however, which is that a server > with a zero weight was reported in this color whatever its state (even > down > or switching). > > Also, one of the motivations for the color above was because the NOLB > state > is barely detectable as it's very close to the UP state. > > Since commit 8c3d0be (MEDIUM: Add DRAIN state and report it on the stats > page), > we have the new DRAIN state to show servers with a zero weight. The > colors are > unfortunately very close to those of the MAINT state, and some users were > confused by the disappearance of the blue bars. > > ? > > It seems important for many users that weight=0 is clearly visible on > the stats page, which I tend to agree with. I agree that reporting the > word "DRAIN" is not suited, but functionally it's exactly the same : the > server doesn't take new traffic anymore. So for people heavily relying on > the stats page to monitor their server states during deployments, it seems > important to me that the color remains at least similar. I suspect that > the method we used to have with both the color and the same being reported > based on srvstate is a bit outdated now, and maybe we should try to address > this first (eg: by using a function to get the color to report and another > one to report the description). > > If your patch maintains the blue line for weight==0, then please ignore my > comment above. > > Best regards, > Willy > -- Regards, Malcolm Turnbull. Loadbalancer.org Ltd. Phone: +44 (0)330 1604540 http://www.loadbalancer.org/
