On Wed, Sep 23, 2009 at 1:05 PM, Denis Chapligin <[email protected]> wrote: > Hi > > On Wed, 23 Sep 2009 10:53:51 +0200 > Dejan Muhamedagic <[email protected]> wrote: > > >> The order constraint means: if resource A is not running then >> resource B can't run either. So, in order to stop A, you have to >> stop B first. Though there are non-symmetrical constraints in >> which stop order is not required to be the opposite of the start >> order. > > Ok, i got the idea. So, actually i've expected exactly this behaviour, > but only for start/stop operations. > >> So, if this is not what you want/expect, perhaps you don't need >> an order constraint. Can you describe the resources and how they >> depend on each other. > > I have two nodes (n1,n2) with two XEN resources configred on them, > let call them A and B. The B resource is a virtual machine, running > webserver and stuff. The A resrouce as a virtual machine, running a > MySQL server. Web on the B vm requires mysql on the A vm. Therefore, to > ensure that resources are started in proper order, i've created a order > constraint: > "First A then B". > > So my cluster is working good, resource A is running on n1, resource B > on n2. For some reason i decide to make > some maintenance on node n1 and tell the crm to set that node to > 'standby' state. During the next several seconds i see the following > actions: > > The B resource is stopped on n2 node > The A resource is migrated to n2 node > The B resource is started on n2 node > > > I was expecting that B resource wouldn't be touched at all.
But thats what you asked for. Order (A, B) tells the cluster that B needs A in order to run. So if A is unavailable at some point, then B must be stopped. Either B can run without A (in which case, set score=0) or it cant (stopping B is necessary). > The A > resource was unavailable for less then a second and it didn't > rebooted and it's execution state doesn't changed during migration. _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
