The galera agent has an 'additional_parameter' option that is already exposed to pcs. This option allows us to pass custom arguments directly into mysqld. It turns out that mysqld has an option to set the open files limit "--open-files-limit="
example:
# pcs ... create galera ... additional_parameters="--open-files-limit=4098" ...
Using pcs with these options, we can set the ulimit to whatever we want during the creation of the galera resource.
Full example: Set ulimit to 30,000
#pcs resource create db galera additional_parameters="--open-files-limit=30000" enable_creation=true wsrep_cluster_address="gcomm://node1,node2,node3" meta master-max=3 ordered=true op promote timeout=300s on-fail=block --master
This functionality is already available in the galera ocf script ship. I've tested this and it works. Below is how I verified the agent properly set the ulimit to 4098.
cat /proc/$(pidof mysqld)/limits | grep "Max open files"
Max open files 4098 4098 files