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

[Marius Cornea]

----- Original Message -----
> From: "Raoul Scarazzini" <rasca at redhat.com>
> To: "Marius Cornea" <mcornea at redhat.com>
> Cc: rdo-list at redhat.com
> Sent: Wednesday, October 7, 2015 1:18:40 PM
> Subject: Re: [Rdo-list] How to know which galera server haproxy is pointing in an overcloud HA env
> 
> 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?

I was just suggesting a way to see to which of the backend nodes haproxy is directing the traffic. Please see the attachment.  

> 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
> 
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