That is not terminating a service. That is terminating the service
supervision subsystem. If you kill the process that actually does the
restarting, you really should not expect that process to then restart
anything. The behaviour of runsv in response to SIGTERM is documented
in its manual; as are the ways to properly tell it to terminate a
service, as opposed to what you did here.
root 10647 10592 0 7月13 ? 00:00:00 /opt/LifeKeeper/sbin/runsv lkcheck
[root@nodeA ec2-user]# kill 10647 12521
Use the runit manual in preference to the LifeKeeper manual here, too.
In particular learn the use of runit commands like
# /opt/LifeKeeper/sbin/sv status /opt/LifeKeeper/etc/service/*
rather than the clumsy and error-prone grepping of the process list that
is given in the LifeKeeper manual.