Open Stack

Hello,

python-memcached badly handles connections during a flush on reconnect and
so connections can grow up exponentially [1].

I don't know if it is the same issue that you faced but it could be a track
to follow.

On oslo.cache a fix has been submitted but it is not yet merged [2].

[1] https://bugs.launchpad.net/oslo.cache/+bug/1888394
[2] https://review.opendev.org/#/c/742193/

Le ven. 11 sept. 2020 à 23:29, Tony Liu <tonyliu0592 at hotmail.com> a écrit :

> Hi,
>
> Is there any guidance or experiences to estimate the number
> of memcached connections?
>
> Here is memcached connection on one of the 3 controllers.
> Connection number is the total established connections to
> all 3 memcached nodes.
>
> Node 1:
> 10 Keystone workers have 62 connections.
> 11 Nova API workers have 37 connections.
> 6 Neutron server works have 4304 connections.
> 1 memcached has 4973 connections.
>
> Node 2:
> 10 Keystone workers have 62 connections.
> 11 Nova API workers have 30 connections.
> 6 Neutron server works have 3703 connections.
> 1 memcached has 4973 connections.
>
> Node 3:
> 10 Keystone workers have 54 connections.
> 11 Nova API workers have 15 connections.
> 6 Neutron server works have 6541 connections.
> 1 memcached has 4973 connections.
>
> Before I increase the connection limit for memcached, I'd
> like to understand if all the above is expected?
>
> How Neutron server and memcached take so many connections?
>
> Any elaboration is appreciated.
>
> BTW, the problem leading me here is memcached connection timeout,
> which results all services depending on memcached stop working
> properly.
>
>
> Thanks!
> Tony
>
>
>

-- 
Hervé Beraud
Senior Software Engineer
Red Hat - Openstack Oslo
irc: hberaud
-----BEGIN PGP SIGNATURE-----
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=ECSj
-----END PGP SIGNATURE-----
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstack.org/pipermail/openstack-discuss/attachments/20200914/b63d5e1f/attachment-0001.html>