Hello list. I'm implementing peers in order to share rps and other metrics
between all instances of a haproxy cluster, so I have a global view of these
data. Here is a snippet of my poc which simply does a request count:
global
localpeer h1
...
listen l1
...
http-request track-sc0 int(1) table p/t1
http-request set-var(req.gpc0) sc_inc_gpc0(0)
http-request set-var(req.gpc0) sc_get_gpc0(0,p/t2),add(req.gpc0)
http-request set-var(req.gpc0) sc_get_gpc0(0,p/t3),add(req.gpc0)
http-request return hdr x-out %[var(req.gpc0)]
peers p
bind :9001
log stdout format raw local0
server h1
server h2 127.0.0.1:9002
server h3 127.0.0.1:9003
table t1 type integer size 1 store gpc0
table t2 type integer size 1 store gpc0
table t3 type integer size 1 store gpc0
Our biggest cluster has actually 25 haproxy instances, meaning 25 tables per
instance, and 25 set-var + add() per request per tracking data. On top of that
all the 25 instances will share their 25 tables to all of the other 24
instances. Build and maintain such configuration isn't a problem at all because
it's automated, but how does it scale? Starting from how much instances should
I change the approach and try, eg, to elect a controller that receives
everything from everybody and delivers grouped data? Any advice or best
practice will be very much appreciated, thanks!
~jm
