Re: [atomic-devel] Fedora 26 change: using overlayfs as default

[Daniel J Walsh <dwalsh redhat com>]

On 12/13/2016 02:18 PM, Dusty Mabe wrote:
>
> On 12/13/2016 01:02 PM, Colin Walters wrote:
>> On Tue, Dec 13, 2016, at 12:45 PM, Clayton Coleman wrote:
>>> Are the POSIX issues in applications running on overlay mostly resolved now?  I.e. if we flipped the default would be reasonably able to support a diverse range of Linux workloads without the risk that previously existed?
>> overlayfs will never be fully POSIX compatible, but I think that's OK,
>> because remember - you shouldn't use overlayfs for persistent data,
>> or really anything that's not code/config files (and we want to get
>> to where that's overlayfs-type semantics for builds, and read-only
>> for deployment).  Data should be in Kube persistent volumes etc.
>>
>> I think the thing to focus on is tools that are run during builds - the
>> yum-in-overlayfs bug is a good example, because the RPM database
>> *is* a database which is the type of workload that's going to
>> be sensitive to the overlayfs semantics.  How many of those
>> are there?  Probably not many, I suspect most of the compat
>> issues with userspace have been shaken out by now.
>>
>> (But long term we may end up in a situation where people
>>  who want to run e.g. rhel5's yum in a container need to
>>  somehow fall back to devmapper)
>>
> So if we were to propose the "overlayfs as default" change for all of
> Fedora, would you consider that to be problematic considering your 
> "you shouldn't use overlayfs for persistent data," stance. In the case
> of a user running pet containers on their local desktop environment,
> what is the sentiment?
>
> Dusty
> _______________________________________________
> cloud mailing list -- cloud lists fedoraproject org
> To unsubscribe send an email to cloud-leave lists fedoraproject org
Yes I might hesitate to run PET Containers in Overlay.  I hope to
get to the point where you can run different container workloads
on different backends.  It might be better to run a PET Container on
OSTree using runc and not going through the client server operation
of docker.