Re: [atomic-devel] Friends don't let friends run Docker on loopback in production

[Radek Vykydal <rvykydal redhat com>]

On 04/15/2015 05:51 PM, Colin Walters wrote:
> Hi,
>
> I've seen several people using Docker on loopback; this is the default if you use a mainline system + yum install Docker, as opposed to an Atomic host which uses https://github.com/projectatomic/fedora-productimg-atomic and https://github.com/projectatomic/docker-storage-setup
>
> I submitted this:
>
> https://github.com/docker/docker/pull/12404
>
> However, I think we can do more here.
>
> - Anaconda UI for reserving a thin pool

I'd rather reserve space (in root's VG) for docker-storage-setup 
creating thin pool, as in Atomic Host?

Some thoughts regarding installation:

Given the space for docker thinpool needs to be reserved during 
installation (because of not shrinkable root's xfs), we seem to be 
looking for an easily accessible installer option to say "I want to use 
docker with this installation"[1]. Which could be something like:

autopart --docker-pool

kickstart option, optionally with XGB or X% size setting. (Assuming the 
space on root's VG will be used.)

The option does not map trivially to GUI, perhaps it will require more 
fine-grained "Automatically configure partitioning" choice (similar to 
ks options?) or the "I want to use docker" being exposed elsewhere on 
its own (ie a checkbox below "Automatically configure partitioning"), 
mapping to autopart --with-docker-pool ks method internally .

What needs to happen when user wants to use docker (with thinpool) is:

1) reserve space for thinpool (on root's VG)
2) create thinpool
3) configure docker to use thin pool (/etc/sysconfig/docker-storage)

I think the current Atomic approach: 1) in anaconda, 2),3) in 
docker-storage-setup after reboot could be the way to go for the 
mainline system too. To make this happen automatically it would mean (if 
"I want to use docker") enabling d-s-s service in installer, and 
installer would also need to ensure the service is installed, and docker 
is installed (docker owns /etc/docker/docker-storage updated by d-s-s). 
But we could also just do 1) in installer and let user do following 
steps (install docker, docker-storage-setup and run d-s-s).

[1] Of course, we can also document kickstarts that would produce the 
same installation, plus some other scenarios, ie using VG on iscsi 
device for thinpool.


Radek