chef/cookbooks/corosync/templates/default/corosync.service.override.erb
[Service]
ExecStartPre=/usr/bin/test ! -e <%= @block_corosync_file %>
ExecStartPost=/usr/bin/touch <%= @block_corosync_file %>
# This doesn't override the service, but append a new command to run
ExecStop=/usr/bin/rm -f <%= @block_corosync_file %>