On Tue, 2020-12-15 at 17:02 +0300, Andrei Borzenkov wrote: > On Tue, Dec 15, 2020 at 4:58 PM Tony Stocker <[email protected]> > wrote: > > > > I'm trying to figure out the best way to do the following on our > > 2-node clusters. > > > > Whichever node is the primary (all services run on a single node) I > > want to create a file that contains an identity descriptor, e.g. > > /var/local/project/identity and the contents are "httpserver". This > > is > > so that we can utilize this file in cron scripts (and other > > programs) > > to determine on which system log files should get rotated, services > > should get HUP'd, etc. When the resource group moves between nodes, > > this file gets deleted on the (now) inactive node and written to on > > the active node. > > > > You could simply query whether a specific resource (group) is active > on the node where your script runs. I used a similar approach in two > node cluster (in this case I simply needed to make sure only one node > runs cron job so I checked for CB master). > > > Is there already a resource agent that does this? If so, could > > someone > > point me at it? > > > > If not, what's the best way to accomplish this? Is it necessary to > > write a complete resource agent script just to do this? Or is there > > a > > simpler way? > > > > Thanks for your help
Just for fun, some other possibilities: You could write your script/cron as an OCF RA itself, with an OCF_CHECK_LEVEL=20 monitor doing the actual work, scheduled to run at whatever interval you want (or using time-based rules, enabling it to run at a particular time). Then you can colocate it with the workload resources. Or you could write a systemd timer unit to call your script when desired, and colocate that with the workload as a systemd resource in the cluster. Or similar to the crm_resource method, you could colocate an ocf:pacemaker:attribute resource with the workload, and have your script check the value of the node attribute (with attrd_updater -Q) to know whether to do stuff or not. -- Ken Gaillot <[email protected]> _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/
