On 05/06/2013, at 5:08 AM, Ferenc Wagner <[email protected]> wrote: > Dejan Muhamedagic <[email protected]> writes: > >> On Mon, Jun 03, 2013 at 06:19:06PM +0200, Ferenc Wagner wrote: >> >>> I've got a script for resource creation, which puts the new resource in >>> a shadow CIB together with the necessary constraints, runs a simulation >>> and finally offers to commit the shadow CIB into the live config (by >>> invoking an interactive crm). This works well. My concern is that if >>> somebody else (another cluster administrator) changes anything in the >>> cluster configuration between creation of the shadow copy and the >>> commit, those changes will be silently reverted (lost) by the commit. >>> Is there any way to avoid the possibility of this? According to >>> http://article.gmane.org/gmane.linux.highavailability.pacemaker/11021, >>> crm provides this functionality for its configure sessions [*], but the >>> shadow CIB route has good points as well (easier to script via cibadmin, >>> simulation), which I'd like to use. Any ideas? >> >> Record the two epoch attributes of the cib tag at the beginning >> and check if they changed just before applying the changes. > > Maybe I don't understand you right, but isn't this just narrowing the > time window of the race? After all, that concurrent change can happen > between the epoch check and the commit, can't it?
The CIB will refuse to accept any update with a "lower" version: http://clusterlabs.org/doc/en-US/Pacemaker/1.1-pcs/html/Pacemaker_Explained/_configuration_version.html _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
