[Pacemaker] promote determent of mysql RA

[Junko IKEDA]

Hi,

I'm trying to set up MySQL Replication enviroment .
glance around mysql RA, it uses "crm_master" to deter the promotion of
the out-of-sync slave node.

https://github.com/ClusterLabs/resource-agents/blob/master/heartbeat/mysql#L496

	elif ocf_is_ms; then
	    # Even if we're not set to evict lagging slaves, we can
	    # still use the seconds behind master value to set our
	    # master preference.
	    local master_pref
	    master_pref=$((${OCF_RESKEY_max_slave_lag}-${secs_behind}))
	    if [ $master_pref -lt 0 ]; then
		# Sanitize a below-zero preference to just zero
		master_pref=0
	    fi
	    $CRM_MASTER -v $master_pref
	fi

mysql RA sets "0" as the attribute score using crm_master.
but, if there is only one node (this node might be out-of-sync),
it seems that Pacemaker ignore its socre and this node will be
promoted even as it is out-of-sync.
I think mysql RA should be set "-INFINITY" in this case. Is it correct?

I found the following comment in drbd RA,
but this issue regarding negative master scores has already been
resolved in the latest Pacemaker.

http://git.drbd.org/?p=drbd-8.3.git;a=blob;f=scripts/drbd.ocf;h=06ffed1dc5cbf6db4c2809d33b4f40da2215d628;hb=HEAD#l410

 410         *)
 411                 # Our local disk is not up to date.
 412                 # Our peer is not available.
 413                 # We have no access to useful data.
 414                 # DRBD would refuse to be promoted, anyways.
 415                 #
 416                 # set_master_score -INFINITY
 417                 # Too bad, at least with current (Oktober 2009) Pacemaker,
 418                 # negative master scores cause instance stop;
restart cycle :(
 419                 # Hope that this will suffice.
 420                 remove_master_score


Regards,
Junko IKEDA

NTT DATA INTELLILINK CORPORATION