[Lxc-users] Container size minialisation

[Gordon Henderson]

On Mon, 12 Dec 2011, István Király - LaKing wrote:

> Hi folks.
>
> I'm trying to compose a system, where lxc containers behave like virtual 
> hosts for a web server.
>
> As next step I would like to minimize container size. My question is, 
> what the best, most elegant and fail proof  technique for that?
>
> At this moment I'm thinking of a "master container" and "slave 
> containers" where the /usr folder for example in the slave containers is 
> a mount from the master container. That gives a significant size drop 
> already, from 400 to 40 megabytes.
>
> I would like to keep the containers really minimal. 4 megabyte should be 
> small enough.
>
> Lets say only some important files in /etc ....
>
> Has anyone any experience with this technique?   Thank you for sharing.

I use something similar for my hosted PBXs (asterisk).

Each PBX container mounts a commonn set of directories from teh host for 
the asterisk installation - e.g. the asterisk binaries, libraries, modules 
and sounds. also a common set for apache. This is all in the fstab 
referenced from each containers config file, so they're all bind-mounted 
at container start time. (read only too)

One thing to beware of - you can't share everything like this - e.g. /usr 
- which I initially thought I could - well, maybe I could, but doing 
things like apt-get update in one container would potentially update files 
in /usr in all containers which might not be the best thing. You could 
probably do it with care though - I simply can't be bothered.

I have to say: I'm not really that bothered about disk space - it's not a 
big deal. I do it that way as it makes it easier to update asterisk over 
all the containers. My "LAMP" type containers don't do any of this.

Gordon