Re: [libvirt] RFC: virInterface change transaction API

On 04/19/2011 10:59 AM, Dan Kenigsberg wrote: >On Mon, Apr 18, 2011 at 05:53:05PM +0100, Daniel P. Berrange wrote: >>On Thu, Apr 14, 2011 at 04:03:03PM +0300, Dan Kenigsberg wrote: >>>On Fri, Apr 08, 2011 at 03:31:05PM -0400, Laine Stump wrote: >>>>1) libvirt >>>> >>>> At the libvirt layer, this feature just requires 3 new APIs, which >>>> are directly passed through to netcf: >>>> >>>> virInterfaceChangeStart(virConnectPtr conn, unsigned int flags); >>>> virInterfaceChangeCommit(virConnectPtr conn, unsigned int flags); >>>> virInterfaceChangeRollback(virConnectPtr conn, unsigned int flags); >>>> >>>> For the initial implementation, these will be simple passthroughs >>>> to similarly named netcf functions. (in the future, it would be >>>> useful for the server side of libvirt to determine if client<->server >>>> connectivity was lost due to the network changes, and automatically >>>> tell netcf to do a rollback). >>>When such a feature is added, we should make it dependent on FLAG_AUTO_ROLLBACK >>>passed to ChangeStart. Higher levels on the management stack may want full >>>controll over when rollback happens. >>I don't think a AUTO_ROLLBACK flag is sufficient. You'd almost certainly >>want to pass some info such as hostname/port number to test, and perhaps >>a test timeout in milliseconds, and perhaps a retry count. >Yes, that's why I wanted complete control over auto rollback, when it is >inroduced. What about the rollback that takes place at boot time if the changes haven't been committed? Should that *always* happen, or should it be controllable by flags as well. I had intended that at least that automatic rollback would be present in the first implementation...