No as long as the storage is modified before the first start of the docker daemon and the first execution of docker-storage-setup, it should be fine.
On 11/17/2016 07:54 PM, Subhendu Ghosh wrote: > > Assuming cloud-init can also select the storage or is that too late in > the process? > > > On Nov 16, 2016 15:58, "Vivek Goyal" <vgo...@redhat.com > <mailto:vgo...@redhat.com>> wrote: > > On Wed, Nov 16, 2016 at 03:19:06PM -0500, Stephen Gallagher wrote: > > On 11/16/2016 03:09 PM, Vivek Goyal wrote: > > > On Wed, Nov 16, 2016 at 03:01:06PM -0500, Stephen Gallagher wrote: > > >> On 11/16/2016 02:56 PM, Vivek Goyal wrote: > > >>> On Wed, Nov 16, 2016 at 02:49:25PM -0500, Stephen Gallagher > wrote: > > >>>> On 11/16/2016 02:40 PM, Vivek Goyal wrote: > > >>>>> On Wed, Nov 16, 2016 at 02:32:46PM -0500, Daniel J Walsh > wrote: > > >>>>>> We would like to change the docker container storage to > default to > > >>>>>> Overlayfs2 in Fedora 26. But we have a problem on Atomic > Host and > > >>>>>> Fedora Server distributions. > > >>>>>> > > >>>>>> > > >>>>>> Currently docker-storage-setup defaults to devicemapper > and is hard > > >>>>>> coded to setup a thinpool of 40% of remaining disk. > Otherwise it sets > > >>>>>> up loopback devices on the root file system. > Devicemapper is nice > > >>>>>> since it works with thinpools and can automatically > expand the storage > > >>>>>> if the disk space is getting used up. > > >>>>>> > > >>>>>> Moving to Overlay, we can more easily use the root file > system directly, > > >>>>>> which would be fine for Fedora Workstation. We want to > preserve the use > > >>>>>> of the remaining storage for Overlay on AH and Fedora > Server, since > > >>>>>> this would give a user flexibility to switch back to > using devicemapper > > >>>>>> if they had problems with the Overlay driver. > > >>>>> > > >>>>> And being able to do so basically involves following. > > >>>>> > > >>>>> - docker-storage-setup creates a logical volume from free > space > > >>>>> - Creates a filesystem on that logical volume > > >>>>> - Mounts that logical volume on the directory which docker > is going to > > >>>>> use. > > >>>>> > > >>>>> mount /dev/docker-vg/foo /var/lib/docker/ > > >>>>> > > >>>>> - Now when docker users overlay2 graph driver, all the > images, containers > > >>>>> and associated metadata will be stored outside the root > filesystem and > > >>>>> onto /dev/docker-vg/foo logical volume. > > >>>>> > > >>>>>> We can not as easily > > >>>>>> support the expanding disk for Overlay since we will not > use using thinpool. > > >>>>> > > >>>>>> > > >>>>>> We have looked at options to hard code OverlayFS with the > defaults, > > >>>>> > > >>>>> If we always mount /var/lib/docker on on /dev/vg/foo for > overlay2 driver > > >>>>> this will be a regression w.r.t current behavior. So I > would not > > >>>>> recommend changing current behavior. I think this should > be an opt-in. > > >>>>> We are working on provide a config knob to elect this > behavior and > > >>>>> atomic host and fedora server will have to opt-in somehow. > > >>>>> > > >>>>> I think it will be easy for atomic host as they already > drop something > > >>>>> in /etc/sysconfig/docker-storage-setup. Not sure how > fedora server > > >>>>> variant will do it. > > >>>>> > > >>>> > > >>>> > > >>>> Today, Fedora Server relies on whatever is the default for > docker-storage-setup. > > >>>> We just tell Anaconda to reserve up to 15GiB by default for > the / partition and > > >>>> then it puts all remaining free space (on drives selected > to be used by > > >>>> Anaconda) into a single logical volume with no partitions. > > >>>> > > >>>> It's a very easy thing for us to drop a different config > file for > > >>>> docker-storage-setup into place for Server. So if that's > all we need to do, let > > >>>> me know and I'll work it up. > > >>> > > >>> Ok, that sounds good. We are working on providing a knob to > opt-in new > > >>> behavior. I think all you have to drop in config file will > be something > > >>> like. > > >>> > > >>> /etc/sysconfig/docker-storage-setup > > >>> > > >>> STORAGE_DRIVER=overlay2 > > >>> YET_TO_BE_NAMED_OPTION=VAL > > >>> > > >>> So upstream default will continue to be devicemapper. We > will have to > > >>> modify fedora workstation, fedora server and atomic host > infrastructure > > >>> to opt-in for overlay2. > > >>> > > >> > > >> Why exactly does this need to be opt-in? Why wouldn't we just > change the default > > >> on Fedora Server to use overlay2 instead of devicemapper? > > >> > > >> I think I'm missing some key part of the problem here. > > > > > > I mean it will be devicemapper in upstream project. And > distributions will > > > have to opt-in for overlay2. > > > > > > And I think one reason being that rhel uses same git tree and > we don't > > > want to switch to overlay2 by default for rhel yet. > > > > > > overlay2 will be an experiment on fedora first as default and > if it works > > > well, then change default upstream too. > > > > OK, when you said "opt-in", I was assuming you meant that from > the user's > > perspective (as in having the user make an explicit choice). > What you meant was > > that Server would carry a different default from the upstream > project. That's > > easy enough to accomplish (we can do the same for Atomic as well). > > > > The packaging guidelines for this are here: > > > https://fedoraproject.org/wiki/Packaging:Per-Product_Configuration > <https://fedoraproject.org/wiki/Packaging:Per-Product_Configuration> > > > > Of course, that's only necessary if we want Server (and Atomic) > to differ from > > Workstation and/or non-productized Fedora. If they're all going > to switch to > > overlay2, then it's just a trivial matter. > > I think all are going to switch to overlay2 by default. But there will > be on difference. Fedora workstation will like to have its overaly2 > setup on top of rootfs. While Fedora Server and Atomic Host will like > to carve out extra logical volume from free space and setup overlay2 > on top of that. > > So there will be total of two config options. One will be same in all > 3 variants. While second one will be used only by server and atomic > host variants. > > /me goes to read per product configuraiton link now. > > Vivek > _______________________________________________ > devel mailing list -- devel@lists.fedoraproject.org > <mailto:devel@lists.fedoraproject.org> > To unsubscribe send an email to > devel-le...@lists.fedoraproject.org > <mailto:devel-le...@lists.fedoraproject.org> > > > > _______________________________________________ > devel mailing list -- devel@lists.fedoraproject.org > To unsubscribe send an email to devel-le...@lists.fedoraproject.org
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