[Neutron] memchached connections

Radosław Piliszek radoslaw.piliszek at gmail.com
Sat Sep 12 09:41:24 UTC 2020


I believe you are hitting [1].

We have recently worked around that in Kolla-Ansible [2].

We'd like to get clarifications on whether the workaround is the right
choice but it seems to work. :-)

[1] https://bugs.launchpad.net/keystonemiddleware/+bug/1883659
[2] https://review.opendev.org/746966

-yoctozepto

On Sat, Sep 12, 2020 at 4:34 AM Tony Liu <tonyliu0592 at hotmail.com> wrote:
>
> I restarted neutron-server on all 3 nodes. Those memcached
> connections from neutron-server are gone. Everything is back
> to normal. It seems like that memcached connections are not
> closed properly in neutron-server. The connections pile up
> over time. Is there any know issue related? Could any Neutron
> experts comment here?
>
> Thanks!
> Tony
> > -----Original Message-----
> > From: Tony Liu <tonyliu0592 at hotmail.com>
> > Sent: Friday, September 11, 2020 2:26 PM
> > To: openstack-discuss <openstack-discuss at lists.openstack.org>
> > Subject: memchached connections
> >
> > 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
>
>



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