[lxc-users] Recent LXC / LXD and shared file systen infrastructures

[Guido Jäkel]

On 19.11.2015 21:58, Serge Hallyn wrote:
>> By the way i would prefer any kind of textual format (even a "xml-hell") for such things like a configuration information over any proprietary representation because it will violate KISS but yield marginal benefits for the user of an application. Of course it's "much simpler" for the developers of this application ;) But an user is enforced to convert it forward to and back from some textual representation if he want to deal with it.
> 
> Well the representation is certainly not proprietary :)  I do also prefer
> plaintext files, but the winning argument was that if you have tens of
> thousands of containers (not all running), and you want to look for all
> the ones which have device X enabled, a db search is quick, whereas
> parsing not only all the config files but also all the included files
> will be very slow.
>

I know you would answer with that ;) And because you admit about plaintext files, we're right, both. And the extreme of tens of thousands of containers, where the difference in performance will be noticeable and will legitimate a term like "very slow" is one striking picture. Comparing the time need to type-in some well known grep, sed or other unix standards versus to study the documentation of a specific db tool might be another one. 

> Ok, if you really aren't going to be creating them, then you can just keep your
> containers stored as they are now, and just have each node keep a database with
> container configuration.  You could even hack something where you have a dummy
> 'image' with empty rootfs and basic config, lxc init dummy c1, bind mount the
> rootfs you really want onto /var/lib/lxd/containers/c1/rootfs, and start the
> container - but that isn't guaranteed to work long-term.

Good clue - this mount and unmount action might be done by using the hooks. And if required at all, some additional information about this might be stored in the dummy image.

I'll better see what LXD expect and what I would like, if i'm able to play with this in real. And I hope that I soon get the permission to start with - to honor the excellent work of the developers like you by using it.

Thank you so far

Guido