Re:Lmctfy: Google's Linux application container stack
by jamesaguilar on Thursday October 03, 2013 @01:16AM
(#6487322)
> useful values for the container spec
Are you referring to the container spec in the proto file? https://github.com/google/lmctfy/blob/master/include/lmctfy.... Which attributes are you having trouble setting a useful value for?
Re:Lmctfy: Google's Linux application container stack
by nickstinemates on Thursday October 03, 2013 @01:38AM
(#6487381)
According to the docs all that can be set is cpu and memory limits. So maybe that's the extent of it for now, even though the proto identifies more.
Re:Lmctfy: Google's Linux application container stack
by shykes on Thursday October 03, 2013 @01:37AM
(#6487378)
Thank you! I was scanning .h files for a type declaration.. Silly old-school me :)
Re:Lmctfy: Google's Linux application container stack
by jamesaguilar on Thursday October 03, 2013 @02:34PM
(#6490954)
I only knew because I've worked with the internal analogue of this library recently. Glad I could help.
Re:Lmctfy: Google's Linux application container stack
by menage on Thursday October 03, 2013 @02:46AM
(#6487524)
Most apps running on Google servers are aware that they're running in a shared environment, so they don't need the overhead of virtualized network interfaces. So I doubt that there will be any specific support for network namespaces.
And you can approximate mount namespaces with chroots and bind mounts. (In some ways that's better, since it's a bit easier for a process outside the container to interact with the container's filesystem).
Re:Lmctfy: Google's Linux application container stack
by shykes on Thursday October 03, 2013 @03:22AM
(#6487586)
Damn. This means it's much less useful to me (and 99% of applications outside of google). I guess I could combine lmctfy with a namespacing library of my own. But that's more extra work than I was anticipating.
Re:Lmctfy: Google's Linux application container stack
by thockin on Thursday October 03, 2013 @03:30AM
(#6487609)
Namespaces will be coming, but we're not there yet. This captures some of what we are already doing internally, but not all of it, yet.
Re:Lmctfy: Google's Linux application container stack
by SEJeff on Thursday October 03, 2013 @08:52PM
(#6493120)
Perhaps they'd be open to a collaboration where you add that functionality and then you use it to make docker (even more!) awesome.
Re:Lmctfy: Google's Linux application container stack
by justincormack on Thursday October 03, 2013 @04:46PM
(#6491910)
The namespacing part is much simpler, if you have specific use cases.
* Building is relatively straightforward on an Ubuntu system. You'll need to install re2 from source, but that's about it.
* No configuration necessary to start playing. lmctfy just straight up mounts cgroups and starts playing in there.
* Containers can be nested which is nice.
* I really couldn't figure out useful values for the container spec. Even the source doesn't seem to have a single reference - it's all dynamically registered by various subsystems in a rather opaque way. I opened a few issues to ask for more details.
* This is a really low-level tool. Other than manipulating cgroups it doesn't seem to do much, which is perfect for my particular use case (docker integration). I couldn't figure out how to set namespaces (including mnt and net namespaces which means all my containers shared the host's filesystem and network interfaces). I don't know if that functionality is already in the code, or has yet to be added.
* Given the fairly small footprint, limited feature set, and clean build experience, this really looks like an interesting option to use as a backend for docker. I like that it carries very little dependencies. Let's see what the verdict is on these missing features.