On Mon, Oct 12, 2020 at 09:12:50AM -0400, Cole Robinson wrote:
On 10/12/20 5:05 AM, Daniel P. Berrangé wrote:
On Mon, Oct 12, 2020 at 10:55:52AM +0200, Michal Privoznik wrote:
On 10/12/20 10:50 AM, Daniel P. Berrangé wrote:
On Sun, Oct 11, 2020 at 07:44:36PM -0400, Cole Robinson wrote:
If storage migration is requested, and the destination storage does not exist on the remote host, qemu's migration support will call into the libvirt storage driver to precreate the destination storage.
The storage driver virConnectPtr is opened too early though, adding an unnecessary dependency on the storage driver for several cases that don't require it. This currently requires kubevirt to install the storage driver even though they aren't actually using it.
Push the virGetConnectStorage calls to right before the cases they are actually needed.
This pushes the connection open attempts inside a loop body. So if the VM has multiple disks, then we're going to be repeatedly opening and closing the connection which is not desirable.
I think we need a global connection across all disks, which is lazy opened on first access.
Doesn't virGetConnectStorage() cache the connection?
Yes & no.
You can call virSetConnectStorage(conn) to populate the cache with a pre-opened connection. If you haven't done that, then a new connection will be opened every time. The ltter is what this code will be doing.
What is the use case for not caching the connection by default?
It is a matter of figuring out an invalidation strategy, so we don't keep the other daemons running continuously when no client is actually triggering their usage.
virSetConnect* has very few users, but virGetConnect* is sprinkled in many places, including multiple uses in generic code in domain_conf.c. Can this be done as part of virGetConnect*?
Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|