On Tue, Jan 20, 2015, at 06:27 AM, Jan Zelený wrote:
You are probably right, I might have misunderstood what you actually propose. Does it mean that you actually don't require this part to be implemented at all and you can go with what's in /var without any distribution-wide changes?
Fedora 21 Atomic does work with a current F21 packageset. For example Docker stores state in /var/lib/docker, and no changes were required to the docker RPM or or rpm-ostree for this.
(Although an aside, Fedora 21 Atomic also stores docker images in a LVM volume which means they would need special factory reset handling if the feature was implemented)
In other words, do you propose this change to be gradually implemented where it makes sense?
Right, on demand. If there's a Fedora RPM that doesn't work with this scheme and is desirable to use by a 3rd party or by the Fedora Atomic subproject, we'd engage with the RPM maintainer to figure out a solution.
Thank you for the additional explanation. Now I think that the problem is not in what you want but in possibly ambiguous specification. What I'm afraid of is that some people will use this opportunity to push through fully transient /var.
There's a commit to OSTree which does make fully transient /var happen out of the box if the underlying / is read-only: https://git.gnome.org/browse/ostree/commit/?id=ff6883ca0655ac8844cd783caf6a7...
Which is pretty nice for some use cases, but definitely not the default =)
At a high level, I do agree this part of the change needs analysis, and I'm glad you brought it up. In the end I think the risk here is going to vary a lot per package.
For example, I need to look closely at the alternatives system.
But I certainly don't want to break the traditional install model - among other things, it's going to be a while before rpm-ostree would be a usable way to run my desktop, and also packages need to be backportable to older branches, etc.