[systemd-devel] We are working on trying to scale up to > 1000 containers.

[Kok, Auke-jan H]

On Thu, Jun 20, 2013 at 12:23 PM, Lennart Poettering
<lennart at poettering.net> wrote:
> On Tue, 18.06.13 09:11, Daniel J Walsh (dwalsh at redhat.com) wrote:
>
>> One concern we have is what will happen to systemd if we start 1000 services
>> at boot.
>>
>> systemctl start httpd_sandbox.target
>>
>> For example.
>>
>> Is there anything we can do to throttle the start of so many unit files.  Or
>> would systemd do something itself.
>
> So, we have rate limits on some things. We maintain per-service
> ratelimits, and a ratelimit in the main even loop. However, that's
> really just a last resort thing. Basically, if the event loop spins more
> often than 50.000 times per second we will just totally block execution
> for 1s. So things get awfully slow when we do too much stuff so that we
> don't consumer 100% CPU forever, and that's all.
>
> I have no experience with running this many services on a machine. I am
> sure we can add various bits here and there to make sure things scale
> nicely for this. But for that I'd really like some performance data
> first, i.e. what actually really happens with the current code.

I'd be very interested to see at least a bootchart and systemd-analyze
plot of this... please post them to share!

Auke