[libvirt] overlayfs support to lxc driver

Vasiliy Tolstov v.tolstov at selfip.ru
Mon Mar 2 15:22:39 UTC 2015


2015-03-02 16:59 GMT+03:00 Daniel P. Berrange <berrange at redhat.com>:
> Conceptually creating a target for the overlay is easy, the difficult
> question is how do we expect apps to actually manage the overlays once
> created. In particular at which point do they get deleted. I don't
> think we would want delete them at container shutdown, at least not
> for persistent containers - it could work for transient containers.
> At the same time we would definitely not want to do it during undefine
> either since that is really intended to only remove the config. Deleting
> the data could take a non-negligble amount of time to complete if the
> container had made lots of changes to its filesystem vs the backing
> store. So this all suggests and out of band mechanism for overlayfs
> management.
>
> So It feels like we might need to integrate the overlayfs support into
> the storage pools implementation instead. eg in the filesystem storage
> pool driver, we could allow for the creation and deletion of overlays for
> directories. Then the LXC driver would not need any changes at all -it
> would simply point an a directory that's an overlay and use the existing
> type=mount support.


So as i understand i need to add overlayfs like
virStorageBackendFileSystem for example virStorageBackendOvlFileSystem
but i don't understand how can this pool be used in case of many containers.
May be i misunderstand something?

-- 
Vasiliy Tolstov,
e-mail: v.tolstov at selfip.ru
jabber: vase at selfip.ru




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