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Quantum LBaaS is too long to answer at HTTP requests (Grizzly)

asked 2013-06-16 17:50:36 -0600

Emilien Macchi gravatar image


I've deployed Quantum LBaaS on a fresh OpenStack setup (Grizzly 2013.1.2) with HAproxy as the backend driver.

I created a simple LB with 2 webservers (apache2) in backend, associated the VIP to a floating IP and updated the security group port option to allow 80 tcp.

With "while true; do curl -q http://X.X.X.X:8080 && date; done" command, I can see that I get an answer from webserver every 15s which is too long for me.

I would like to know if someone already met this kind of issue, and if it's related to my setup or to Quantum LBaaS service ?

Thank's for support,

Emilien Macchi

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answered 2013-10-16 09:42:57 -0600

rohara gravatar image

Did you create a healthmonitor and associate it with you pool? It is possible to observe slow responses when one of the pool members is down and no healthmonitor is associated with the pool. If the selected backend server is down, haproxy will retry N times before it the request is dispatched to a different backend server. When a healthmonitor is associated with the pool, no member that is down will be considered for the request.

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answered 2013-06-16 18:14:21 -0600

Salvatore gravatar image

It definitely too slow too be true, even by Quantum standards!

This kind of timeout makes me suspect your instances or haproxy are trying to perform some kind of dns resolution before sending the response. You might want to try with tcpdump on the server side.

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You can see TCPdump here :

Emilien Macchi gravatar imageEmilien Macchi ( 2013-06-17 03:39:24 -0600 )edit

It seems that if I change net.ipv4.vs.timeout_timewait value (which is at 15) to 5, it takes 5s to answer.

Emilien Macchi gravatar imageEmilien Macchi ( 2013-06-17 09:42:25 -0600 )edit

The problem seems to be localized in the LBaaS namespace because when I spawn a VM with HAproxy & another with webserver, the HTTP requests are load balanced immediately.

Emilien Macchi gravatar imageEmilien Macchi ( 2013-06-17 12:09:42 -0600 )edit

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Asked: 2013-06-16 17:50:36 -0600

Seen: 348 times

Last updated: Oct 16 '13