[lxc-users] Experience with large number of LXC/LXD containers

[Serge E. Hallyn]

On Tue, Mar 14, 2017 at 02:29:01AM +0100, Benoit GEORGELIN - Association Web4all wrote:
> ----- Mail original -----
> > De: "Simos Xenitellis" <simos.lists at googlemail.com>
> > À: "lxc-users" <lxc-users at lists.linuxcontainers.org>
> > Envoyé: Lundi 13 Mars 2017 20:22:03
> > Objet: Re: [lxc-users] Experience with large number of LXC/LXD containers
> 
> > On Sun, Mar 12, 2017 at 11:28 PM, Benoit GEORGELIN - Association
> > Web4all <benoit.georgelin at web4all.fr> wrote:
> > > Hi lxc-users ,
> 
> > > I would like to know if you have any experience with a large number of
> > > LXC/LXD containers ?
> > > In term of performance, stability and limitation .
> 
> > > I'm wondering for exemple, if having 100 containers behave the same of
> > > having 1.000 or 10.000 with the same configuration to avoid to talk about
> > > container usage.
> 
> > > I have been looking around for a couple of days to found any user/admin
> > > feedback experience but i'm not able to find large deployments
> 
> > > Is there any ressources limits or any maximum number that can be deployed on
> > > the same node ?
> > > Beside physical performance of the node, is there any specific behavior that
> > > a large number of LXC/LXD containers can experience ? I'm not aware of any
> > > test or limits that can occurs beside number of process. But I'm sure from
> > > LXC/LXD side it might have some technical contraints ?
> > > Maybe on namespace availability , or any other technical layer used by
> > > LXC/LXD
> 
> > > I will be interested to here from your experience or if you have any
> > > links/books/story about this large deployments
> 
> 
> > This would be interesting to hear if someone can talk publicly about
> > their large deployment.
> 
> > In any case, it should be possible to create, for example, 1000 web servers
> > and then try to access each one and check any issues regarding the
> > response time.
> > Another test would be to install 1000 Wordpress installations and
> > check again for the response time
> > and resource usage.
> > Such scripts to create this massive number of containers would also be
> > helpful to replicate
> > any issues in order to solve them.
> 
> > Simos
> 
> 
> Yes it's would be very nice to hear about this kind of infrastructure using lxc/lxd 
> I'm not yet ready to make this kind of testing, but if someone would like to work on this with me as a projet, I can provide the technical infrastructure and scripts . 
> That would be nice to provide a good testing case and analyse to share to the community 

It should be pretty simple.  I've done testing like this to test other
software, which implicitly ended up testing lxd.

You'd probably create a first container and publish it locally,

(all commands untested, just an example)

lxc launch ubuntu:xenial template
lxc exec template -- apt -y install nginx
lxc stop template
lxc publish --alias template template

Then do your testing in a loop,

# spin up containers
for i in `seq -f "%04g" 1 1000`; do
        lxc launch template nginx-$i
done

# spin up clients
... etc