[Rdo-list] How to know which galera server haproxy is pointing in an overcloud HA env

[Raoul Scarazzini]

Il giorno 7/10/2015 13:07:30, Marius Cornea ha scritto:
> You can check the haproxy stats dashboard and determine which of the
backend nodes takes the sessions. To access it look for the ip address
haproxy.stats binds to in haproxy.cfg and reach it via http on port 1993.

Hi Marius,
thank you for the answer. This is not so clear to me. What do you mean
with "takes the sessions"? If I understand correctly I need to store
somewhere a delta, because without it how can I know which server is
increasing?
Look at this:

[root at overcloud-controller-1 ~]# echo "show stat" | socat
/var/run/haproxy stdio | grep mysql
mysql,FRONTEND,,,65,87,2000,6290,12411640,28349332,0,0,0,,,,,OPEN,,,,,,,,,1,13,0,,,,0,1,0,13,,,,,,,,,,,0,0,0,,,0,0,0,0,,,,,,,,
mysql,overcloud-controller-0,0,0,65,87,,6290,12411640,28349332,,0,,0,0,0,0,UP,1,0,1,0,0,10271,0,,1,13,1,,1,,2,1,,13,L7OK,200,54,,,,,,,0,,,,0,0,,,,,1,OK,,0,1,0,14961,
mysql,overcloud-controller-1,0,0,0,0,,0,0,0,,0,,0,0,0,0,DOWN,1,0,1,8,2,4651,4676,,1,13,2,,0,,2,0,,0,L7STS,503,65,,,,,,,0,,,,0,0,,,,,-1,Service
Unavailable,,0,0,0,0,
mysql,overcloud-controller-2,0,0,0,0,,0,0,0,,0,,0,0,0,0,UP,1,0,1,6,1,6042,94,,1,13,3,,0,,2,0,,0,L7OK,200,55,,,,,,,0,,,,0,0,,,,,-1,OK,,0,0,0,0,
mysql,BACKEND,0,0,65,87,200,6290,12411640,28349332,0,0,,0,0,0,0,UP,1,0,2,,0,10271,0,,1,13,0,,1,,1,1,,13,,,,,,,,,,,,,,0,0,0,0,0,0,1,,,0,1,0,14961,

As you can see the mysql,overcloud-controller-1 is DOWN, so the choice
is between the other two. From what I can suppose, is the first one the
suspected one, but just because it has a value that increases.
Your suggestion is to double take the value to each server and see which
one increases? What if in that moment there are no connections and the
values remains the same?

Thanks,

--
Raoul Scarazzini
rasca at redhat.com