Hi! I think a concrete use example would be helpful to understand what the new syntaxes are really about...
Regards, Ulrich >>> Kristoffer Grönlund<[email protected]> schrieb am 13.12.2013 um 10:16 in Nachricht <[email protected]>: > Hi everyone, > > As some of you may know, I have started developing crmsh together with > Dejan, and have been working on new features for an eventual > 2.0-release some time next year. > > Location constraints have gotten some new capabilities in recent > versions of Pacemaker, and I have some suggested syntax for support in > crmsh. I'd love to get your comments and feedback on these suggestions, > please let me know what you think! > > Location constraints are now applicable to resource sets, and the > proposed syntax for this is as follows, using pseudo-syntax: > > location <id> { <resource-set> } [<score>:] <node> / rules... > > So, an example would be: > > location foo { A B ( C D ) } inf: node-1 > > The reason I added the { and } around the resource set is to make the > parser at least somewhat unambiguous in this case, otherwise there is no > good way of telling when the resource definitions end and the rest of > the location constraint definition continues. I know there is syntax in > crmsh that already violates this, but my preference is to keep things > unambiguous if possible. > > Lars (lmb) suggested that we might switch to using the { } - brackets > around resource sets everywhere for consistency. My only concern with > that would be that it would be a breaking change to the previous crmsh > syntax. Maybe that is okay when going from 1.x to 2.0, but it also > makes me a bit nervous. :) > > The second new syntax is for resource patterns / regexes. Here my > suggested syntax is as follows: > > location <id> /<pattern>/ [<score>:] <node> / rules... > > Example: > > location prefer-node-1 /*/ 100: node-1 > > The // is a kind of vim-style / perl-style inspired syntax, which at > least to me seems pretty intuitive. Another option would be to try to > automatically detect patterns and generate rsc= or rsc-pattern= in the > XML appropriately, like so: > > location prefer-node-1 * 100: node-1 > > ...but I think I prefer a more explicit syntax. > > I'd especially be curious to know what Chris thinks about this, if > there is already support for these types of constraints in pcs or if > there is some other syntax that might make more sense. Consistency is > always good. :) > > -- > // Kristoffer Grönlund > // [email protected] > _______________________________________________ > Linux-HA mailing list > [email protected] > http://lists.linux-ha.org/mailman/listinfo/linux-ha > See also: http://linux-ha.org/ReportingProblems _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
