mgbutler at nbnet
Sep 10, 2010, 3:02 AM
Post #5 of 5
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Re: Built in Affinity with LVS and LinuxHA?
[In reply to]
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Think I got it - ARP problem.
On 10-09-10 04:53 AM, Mike wrote:
> Thank you for the response Simon. Helpful as always.
>
> I did some testing on this issue tonight and I've discovered an
> interesting issue.
>
> First of all I am using LVS-Tun and I have created a tunnel interface on
> each of my back end servers. This tunnel interface is of course the VIP
> you see below - 172.28.185.54.
>
> When we started our tests this evening all requests were going to one
> back end server, 172.28.185.57. As a test I decided to completely
> shutdown the LVS servers by shutting down LinuxHA which shuts down
> ldirectord.
>
> To my surprise, I was still able to send connections to the VIP. When I
> ssh'ed into the VIP I ended up on the back end server that was receiving
> the connections. Of course the VIP should be down since LVS was down. I
> rebooted both back end servers, started up LVS and like magic everything
> worked. Load balancing was working perfectly.
>
> So the problem was the backend server somehow took ownership of the VIP
> and as a result was grabbing all requests. A reboot resolved it. Can you
> tell me why this may have happened? What could be wrong on my backend
> servers that they would grab the VIP like this?
>
> Any help would be appreciated greatly.
>
> Mike
> On Thu, 2010-09-09 at 18:15 +0900, Simon Horman wrote:
>
>> On Tue, Sep 07, 2010 at 03:57:52PM -0300, Mike wrote:
>>
>>> Hello all,
>>>
>>> I've implemented a LVS cluster using ldirectord and LinuxHA. Here is a
>>> snippet from my ldirectord.cf file:
>>>
>>> virtual=172.28.185.54:8080
>>> protocol=tcp
>>> scheduler=wrr
>>> checktype=connect
>>> checkport=8080
>>> #service=ldap
>>> real=172.28.185.57:8080 ipip
>>> real=172.28.185.58:8080 ipip
>>> #service=http
>>> checktimeout=10
>>> checkinterval=10
>>>
>>> While running tests that hit the index.html page on the VIP above I
>>> noticed that we seem to be hitting the same backend server repeatedly.
>>> When I run the test from another server, we start hitting the other back
>>> end server repeatedly. I'm curious if anyone can tell me if there is a
>>> built in affinity here that I'm missing. I'm thinking that ldirecotor
>>> seems to be smart enough (or dumb enough depending on your point of
>>> view) to notice that a connection attempt from ip address guest will be
>>> sent to the same backend server for productivity reasons.
>>>
>>> Anyone know if thee is a natural built in affinity here?
>>>
>> If you have persistence enabled, then yes that is the expected behaviour.
>> Otherwise its a bit odd.
>>
>
> _______________________________________________
> Linux-HA mailing list
> Linux-HA [at] lists
> http://lists.linux-ha.org/mailman/listinfo/linux-ha
> See also: http://linux-ha.org/ReportingProblems
>
>
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