[Systems] Wiki speed

Sam P. sam at sam.today
Sun Jun 28 06:37:04 EDT 2015

Hi All,

Samuel and I chatted and tested stuff on irc earlier this morning (well,
last night over in you guys part of the world).  Here's where we are at:

*  Docker can actually do cpu limitation in a good way.  We found 2 ways we
can limit the cpu, both of which work pretty well (aka. we tested them)
    - Dedicate docker X cores and use cpu shares.  Effectively saying "if
all of the containers are using the cpu at the same time, you get (my
share)/(total shares) of the cpu pool".  That could work fine, we'd just
need to agree on which cpu cores to use and keep them the same across all
    - We can set a limit to how much (%) of each cpu scheduler period that
the container can use
=> We kinda have found that we can do everything with docker - no hipster
stuff needed

* Docker has good managament/reporting tools.  We deployed (aka. ran the
container) cAdvisor (by Google), which is a nice web interface to the
cpu/ram per container status
    - http://freedom.sugarlabs.org:8080/containers/
    - eg.  Discourse container
    - Will find a solution to why it shows container ids not names on the
list page (because good sysadmins obviously memorise the container id of
every container they launch)

* We now have data to make decisions about what resources to allocate to
the containers and means to limit them to those resources!  Yay!


On Sat, Jun 27, 2015 at 10:08 PM Sam P. <sam at sam.today> wrote:

> Hi Bernie,
> On Sat, Jun 27, 2015 at 3:56 AM Bernie Innocenti <bernie at codewiz.org>
> wrote:
>> On 26/06/15 09:14, Samuel Cantero wrote:
> > I like the approach of using systemd for resource management. Besides,
>> > on an operating system which uses systemd as the service manager process
>> > (not only the ones inside of the container) will be placed in a cgroups
>> > tree. BTW, systemd will replace upstart in Ubuntu 15.04.
>> If we need to upgrade to 15.04 for systemd, I'd go for it even if it's
>> not LTS. We have the ability to experiment on freedom while justice
>> keeps serving production traffic.
> Yeah, systemd is very useful.  I'm pretty sure it has systemd, but I'll
> spin up a droplet on DO to check it very soon.  From memory, systemd got
> shipped on most of the distros recently.
>> When (and *if*) we're satisfied with the stability of systemd containers
>> on 15.04, we'll upgrade justice to the same release. And anyway, as soon
>> as the next LTS comes out we'll upgrade both machines to it, in the same
>> staggered fashion which minimizes surprises.
>> However, systemd-nspawn is relatively new and I haven't heard of any
>> large deployment using it. It may very well be that it's not yet ready
>> for production. So don't count too much on it.
> Hum, I wasn't thinking of using systemd-nspawn.  It is pretty cool, but it
> might not be as production ready.
> I was thinking of using rkt to run containers.  It is backed by coreos so
> it's probably more production ready.  But, since rkt runs in the same UNIX
> style as systemd-nspawn, you can integrate it with systemd unit/.service
> files [1].  This means that you have a simple management system from
> systemd and also a way of allocating resources (CPUQuota and MemoryLimit)
> and monitoring (try "systemctl status display-manager.service").
> I was aiming to test that today, but I'm getting there very slowly.  rkt
> runs appc images although you can convert docker images to appc.  I have no
> idea how you build appc images and can't find the link to a registry or
> anything dockery like that.  Running docker images either involves pulling
> them from a docker registry or converting them (like 10minutes of pure disk
> I/O).  Anyway, that's something to research.
>> > I will look for rtk and runc.io <http://runc.io>.
>> Thanks. Speaking of container management, have you guys tried Kubernetes?
>>    https://github.com/googlecloudplatform/kubernetes
>> Looks a bit too big for our infrastructure, but it also looks pretty
>> well designed and implemented...
> Yeah, it's a cool system.  It doesn't seem to solve out resource limits
> issue - it is built on top of docker I think.
> What's your use case of it?
> Thanks,
> Sam
> [1]
> https://github.com/coreos/rkt/blob/master/Documentation/using-rkt-with-systemd.md
>> --
>>   _ // Bernie Innocenti
>>   \X/  http://codewiz.org
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